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Materials Data on Sm4Cr3Fe31C4 by Materials Project

Sm4Cr3Fe31C4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Sm sites. In the first Sm site, Sm is bonded in a distorted bent 120 degrees geometry to eight Fe and two C atoms. There are a spread of Sm–Fe bond distances ranging from 3.05–3.39 Å. Both Sm–C bond lengths are 2.53 Å. In the second Sm site, Sm is bonded in a distorted bent 120 degrees geometry to one Cr, eight Fe, and two C atoms. The Sm–Cr bond length is 3.23 Å. There are a spread of Sm–Fe bond distances ranging from 3.04–3.40 Å. There are one shorter (2.53 Å) and one longer (2.54 Å) Sm–C bond lengths. In the third Sm site, Sm is bonded in a distorted bent 120 degrees geometry to one Cr, eight Fe, and two C atoms. The Sm–Cr bond length is 3.24 Å. There are a spread of Sm–Fe bond distances ranging from 3.04–3.40 Å. Both Sm–C bond lengths are 2.53 Å. In the fourth Sm site, Sm is bonded in a distorted bent 120 degrees geometry to one Cr, eight Fe, and two C atoms. The Sm–Cr bond length is 3.19 Å. There are a spread of Sm–Fe bond distances ranging from 3.01–3.43 Å. There are one shorter (2.53 Å) and one longer (2.54 Å) Sm–C bond lengths. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded in a 1-coordinate geometry to one Sm, one Cr, and twelve Fe atoms. The Cr–Cr bond length is 2.15 Å. There are a spread of Cr–Fe bond distances ranging from 2.65–2.71 Å. In the second Cr site, Cr is bonded in a 1-coordinate geometry to one Sm, one Cr, and twelve Fe atoms. There are a spread of Cr–Fe bond distances ranging from 2.65–2.71 Å. In the third Cr site, Cr is bonded in a 1-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Cr–Fe bond distances ranging from 2.32–2.75 Å. There are thirty-one inequivalent Fe sites. In the first Fe site, Fe is bonded to two Sm, one Cr, and nine Fe atoms to form distorted FeSm2CrFe9 cuboctahedra that share corners with seven FeSm2CrFe9 cuboctahedra, corners with two CSm2Fe4 octahedra, edges with four FeSm2Cr2Fe8 cuboctahedra, faces with seven FeSm2Cr2Fe8 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 45–46°. There are a spread of Fe–Fe bond distances ranging from 2.43–2.67 Å. In the second Fe site, Fe is bonded to two Sm, two Cr, and eight Fe atoms to form distorted FeSm2Cr2Fe8 cuboctahedra that share corners with seven FeSm2Cr2Fe8 cuboctahedra, corners with two CSm2Fe4 octahedra, edges with four FeSm2CrFe9 cuboctahedra, faces with seven FeSm2CrFe9 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 46–48°. There are four shorter (2.44 Å) and four longer (2.45 Å) Fe–Fe bond lengths. In the third Fe site, Fe is bonded to two Sm, one Cr, and nine Fe atoms to form distorted FeSm2CrFe9 cuboctahedra that share corners with six FeSm2CrFe9 cuboctahedra, corners with two CSm2Fe4 octahedra, edges with four FeSm2Cr2Fe8 cuboctahedra, faces with six FeSm2CrFe9 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 45–48°. There are a spread of Fe–Fe bond distances ranging from 2.42–2.67 Å. In the fourth Fe site, Fe is bonded to two Sm, two Cr, and eight Fe atoms to form distorted FeSm2Cr2Fe8 cuboctahedra that share corners with eight FeSm2Cr2Fe8 cuboctahedra, corners with two CSm2Fe4 octahedra, edges with four FeSm2CrFe9 cuboctahedra, faces with eight FeSm2Cr2Fe8 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 46°. There are a spread of Fe–Fe bond distances ranging from 2.43–2.47 Å. In the fifth Fe site, Fe is bonded to two Sm, two Cr, and eight Fe atoms to form distorted FeSm2Cr2Fe8 cuboctahedra that share corners with fourteen FeSm2CrFe9 cuboctahedra, edges with two FeSm3CrFe8 cuboctahedra, faces with ten FeSm2Cr2Fe8 cuboctahedra, and faces with four CSm2Fe4 octahedra. There are a spread of Fe–Fe bond distances ranging from 2.42–2.47 Å. In the sixth Fe site, Fe is bonded in a 12-coordinate geometry to two Sm, one Cr, and nine Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.42–2.67 Å. In the seventh Fe site, Fe is bonded to three Sm, one Cr, and eight Fe atoms to form distorted FeSm3CrFe8 cuboctahedra that share corners with nine FeSm2CrFe9 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with four FeSm2CrFe9 cuboctahedra, faces with eight FeSm2Cr2Fe8 cuboctahedra, and faces with two CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 63–70°. There are a spread of Fe–Fe bond distances ranging from 2.55–2.69 Å. In the eighth Fe site, Fe is bonded to three Sm, one Cr, and eight Fe atoms to form distorted FeSm3CrFe8 cuboctahedra that share corners with ten FeSm2Cr2Fe8 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with three FeSm2Cr2Fe8 cuboctahedra, faces with seven FeSm2CrFe9 cuboctahedra, and faces with two CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 62–71°. There are a spread of Fe–Fe bond distances ranging from 2.56–2.68 Å. In the ninth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. There are one shorter (2.56 Å) and one longer (2.57 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.91 Å. In the tenth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. There are one shorter (2.55 Å) and one longer (2.59 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.91 Å. In the eleventh Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. There are one shorter (2.56 Å) and one longer (2.59 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.91 Å. In the twelfth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. Both Fe–Fe bond lengths are 2.56 Å. The Fe–C bond length is 1.91 Å. In the thirteenth Fe site, Fe is bonded to three Sm and nine Fe atoms to form distorted FeSm3Fe9 cuboctahedra that share corners with ten FeSm2CrFe9 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with three FeSm2CrFe9 cuboctahedra, faces with seven FeSm2Cr2Fe8 cuboctahedra, and faces with two CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 62–69°. There are a spread of Fe–Fe bond distances ranging from 2.55–2.68 Å. In the fourteenth Fe site, Fe is bonded to three Sm, one Cr, and eight Fe atoms to form distorted FeSm3CrFe8 cuboctahedra that share corners with nine FeSm2Cr2Fe8 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with four FeSm2Cr2Fe8 cuboctahedra, faces with eight FeSm2CrFe9 cuboctahedra, and faces with two CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 61–70°. There are a spread of Fe–Fe bond distances ranging from 2.56–2.69 Å. In the fifteenth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. The Fe–Fe bond length is 2.55 Å. The Fe–C bond length is 1.92 Å. In the sixteenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–Fe bond length is 2.55 Å. The Fe–C bond length is 1.91 Å. In the seventeenth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–Fe bond length is 2.55 Å. The Fe–C bond length is 1.91 Å. In the eighteenth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. The Fe–Fe bond length is 2.55 Å. The Fe–C bond length is 1.91 Å. In the nineteenth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. The Fe–Fe bond length is 2.46 Å. The Fe–C bond length is 1.84 Å. In the twentieth Fe site, Fe is bonded in a single-bond geometry to two Cr, four Fe, and one C atom. The Fe–Fe bond length is 2.47 Å. The Fe–C bond length is 1.83 Å. In the twenty-first Fe site, Fe is bonded in a single-bond geometry to two Cr, four Fe, and one C atom. The Fe–Fe bond length is 2.47 Å. The Fe–C bond length is 1.85 Å. In the twenty-second Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. The Fe–Fe bond length is 2.48 Å. The Fe–C bond length is 1.85 Å. In the twenty-third Fe site, Fe is bonded to two Sm, one Cr, and nine Fe atoms to form distorted FeSm2CrFe9 cuboctahedra that share corners with seven FeSm2Cr2Fe8 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with three FeSm2CrFe9 cuboctahedra, edges with two CSm2Fe4 octahedra, and faces with seven FeSm2Cr2Fe8 cuboctahedra. The corner-sharing octahedra tilt angles range from 21–28°. There are a spread of Fe–Fe bond distances ranging from 2.46–2.69 Å. In the twenty-fourth Fe site, Fe is bonded to two Sm, two Cr, and eight Fe atoms to form distorted FeSm2Cr2Fe8 cuboctahedra that share corners with seven FeSm2Cr2Fe8 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with three FeSm2Cr2Fe8 cuboctahedra, edges with two CSm2Fe4 octahedra, and faces with nine FeSm2CrFe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 22–28°. There are one shorter (2.46 Å) and one longer (2.48 Å) Fe–Fe bond lengths. In the twenty-fifth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. The Fe–C bond length is 1.84 Å. In the twenty-sixth Fe site, Fe is bonded in a single-bond geometry to two Cr, four Fe, and one C atom. The Fe–C bond length is 1.85 Å. In the twenty-seventh Fe site, Fe is bonded to two Sm, two Cr, and eight Fe atoms to form distorted FeSm2Cr2Fe8 cuboctahedra that share corners with seven FeSm2Cr2Fe8 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with three FeSm2CrFe9 cuboctahedra, edges with two CSm2Fe4 octahedra, and faces with nine FeSm2CrFe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 22–28°. In the twenty-eighth Fe site, Fe is bonded to two Sm, one Cr, and nine Fe atoms to form distorted FeSm2CrFe9 cuboctahedra that share corners with seven FeSm2CrFe9 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with three FeSm2Cr2Fe8 cuboctahedra, edges with two CSm2Fe4 octahedra, and faces with seven FeSm2Cr2Fe8 cuboctahedra. The corner-sharing octahedra tilt angles range from 22–28°. The Fe–Fe bond length is 2.69 Å. In the twenty-ninth Fe site, Fe is bonded in a single-bond geometry to two Cr, four Fe, and one C atom. The Fe–C bond length is 1.85 Å. In the thirtieth Fe site, Fe is bonded in a single-bond geometry to one Cr, four Fe, and one C atom. The Fe–C bond length is 1.85 Å. In the thirty-first Fe site, Fe is bonded in a distorted single-bond geometry to one Cr and six Fe atoms. There are four inequivalent C sites. In the first C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with ten FeSm2Cr2Fe8 cuboctahedra, corners with two CSm2Fe4 octahedra, edges with two FeSm2Cr2Fe8 cuboctahedra, and faces with six FeSm2Cr2Fe8 cuboctahedra. The corner-sharing octahedral tilt angles are 63°. In the second C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with ten FeSm2Cr2Fe8 cuboctahedra, corners with two CSm2Fe4 octahedra, edges with two FeSm2CrFe9 cuboctahedra, and faces with four FeSm2CrFe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 63–64°. In the third C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with ten FeSm2Cr2Fe8 cuboctahedra, corners with two CSm2Fe4 octahedra, edges with two FeSm2Cr2Fe8 cuboctahedra, and faces with five FeSm2CrFe9 cuboctahedra. The corner-sharing octahedral tilt angles are 63°. In the fourth C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with ten FeSm2CrFe9 cuboctahedra, corners with two CSm2Fe4 octahedra, edges with two FeSm2CrFe9 cuboctahedra, and faces with five FeSm2Cr2Fe8 cuboctahedra. The corner-sharing octahedra tilt angles range from 63–64°.

36 MATERIALS SCIENCE↗

Materials Data on NaCr2FeO10 by Materials Project

NaCr2FeO10 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Na–O bond distances ranging from 2.45–2.82 Å. Cr is bonded to four O atoms to form CrO4 tetrahedra that share corners with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 35–48°. There are a spread of Cr–O bond distances ranging from 1.62–1.74 Å. Fe is bonded to six O atoms to form FeO6 octahedra that share corners with four equivalent CrO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.84–1.99 Å. There are five inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Fe atom. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one Na, one Cr, and one Fe atom. In the third O site, O is bonded in a distorted trigonal planar geometry to one Na, one Cr, and one Fe atom. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and one Cr atom. In the fifth O site, O is bonded in a single-bond geometry to one Na and one Cr atom.

36 MATERIALS SCIENCE↗

1,10-Phenanthroline-Iron Complex-Derived Fe-N-C Electrocatalysts: Enhanced Oxygen Reduction Activity and Stability Through Synthesis Tuning

The development of electrocatalysts composed of earth-abundant elements is essential for advancing the commercial application of Proton Exchange Membrane Fuel Cells (PEMFC). Among these, single-atom electrocatalysts, such as Fe-N-C, show great promise for the oxygen reduction reaction (ORR). This study aims to improve the ORR activity and stability of Fe-N-C electrocatalysts by fine-tuning the straightforward 1,10-phenanthroline-iron complexation synthesis method. Key parameters, including iron-to-phenanthroline ratio, carbon powder surface area, and pyrolysis temperature were systematically varied to evaluate their influence on the resulting electrocatalysts. The findings of this study revealed that the electrocatalysts synthesized with 1,10-phenanthroline (Phen) and high-surface-area Black Pearls (BP) possessed much better ORR activity than electrocatalysts prepared by using Vulcan carbon (lower surface area). Interestingly, electrocatalysts prepared with BP, but with a non-bidentate nitrogen-containing ligand molecule, such as imidazole, showed a much poorer activity, as the resulting material predominantly consisted of inactive structures, such as encapsulated iron nanoparticles and iron oxide, as evidenced by HR-TEM, EXAFS, and XRD. Therefore, the results suggest that only the synergistic combination of the bidentate ligand phenanthroline (Phen) and the high-surface-area carbon support (BP) favored the formation of ORR-active Fe-N-C single-atom species upon pyrolysis. The study also unveiled a significant enhancement in electrocatalyst stability during accelerated durability tests (and air storage) as the pyrolysis temperature was increased from 700 to 1300 °C, albeit at the expense of ORR activity, likely resulting from the generation of iron particles. Pyrolysis at 1050 °C yielded the electrocatalyst with the most favorable balance of activity and stability in rotating disk measurements, while maintaining moderate durability under PEM fuel cell operation. The insights obtained in this study may guide the development of more active efficient and durable electrocatalysts, synthesized via a simple method using earth-abundant elements, for application in PEMFC cathodes.

30 DIRECT ENERGY CONVERSION↗

Materials Data on Sm4Fe34C3 by Materials Project

Sm4Fe34C3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Sm sites. In the first Sm site, Sm is bonded in a distorted bent 120 degrees geometry to nine Fe and two C atoms. There are a spread of Sm–Fe bond distances ranging from 3.06–3.41 Å. Both Sm–C bond lengths are 2.55 Å. In the second Sm site, Sm is bonded in a distorted single-bond geometry to fourteen Fe and one C atom. There are a spread of Sm–Fe bond distances ranging from 3.04–3.34 Å. The Sm–C bond length is 2.56 Å. There are eighteen inequivalent Fe sites. In the first Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.47–2.66 Å. The Fe–C bond length is 1.91 Å. In the second Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.48–2.65 Å. The Fe–C bond length is 1.90 Å. In the third Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.48–2.65 Å. The Fe–C bond length is 1.91 Å. In the fourth Fe site, Fe is bonded to three equivalent Sm and nine Fe atoms to form FeSm3Fe9 cuboctahedra that share corners with fourteen FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with seven FeSm3Fe9 cuboctahedra, faces with ten FeSm3Fe9 cuboctahedra, and a faceface with one CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 66–70°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.67 Å. In the fifth Fe site, Fe is bonded to three equivalent Sm and nine Fe atoms to form distorted FeSm3Fe9 cuboctahedra that share corners with twelve FeSm3Fe9 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with four FeSm3Fe9 cuboctahedra, faces with eight FeSm3Fe9 cuboctahedra, and faces with two CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 62–69°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.68 Å. In the sixth Fe site, Fe is bonded to three equivalent Sm and nine Fe atoms to form FeSm3Fe9 cuboctahedra that share corners with thirteen FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with six FeSm3Fe9 cuboctahedra, faces with eleven FeSm3Fe9 cuboctahedra, and a faceface with one CSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 66–70°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.67 Å. In the seventh Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.38–2.77 Å. In the eighth Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.63–2.76 Å. In the ninth Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form FeSm2Fe10 cuboctahedra that share corners with eight FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with four FeSm3Fe9 cuboctahedra, faces with eight FeSm3Fe9 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. There are two shorter (2.44 Å) and two longer (2.45 Å) Fe–Fe bond lengths. In the tenth Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form FeSm2Fe10 cuboctahedra that share corners with ten FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with six FeSm3Fe9 cuboctahedra, and faces with ten FeSm3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 44°. There are two shorter (2.43 Å) and two longer (2.44 Å) Fe–Fe bond lengths. In the eleventh Fe site, Fe is bonded to two Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with eleven FeSm3Fe9 cuboctahedra, a cornercorner with one CSm2Fe4 octahedra, edges with five FeSm3Fe9 cuboctahedra, faces with nine FeSm3Fe9 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Fe–Fe bond distances ranging from 2.43–2.45 Å. In the twelfth Fe site, Fe is bonded to two Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with fifteen FeSm3Fe9 cuboctahedra, edges with three FeSm3Fe9 cuboctahedra, faces with eleven FeSm3Fe9 cuboctahedra, and faces with three CSm2Fe4 octahedra. There are a spread of Fe–Fe bond distances ranging from 2.42–2.44 Å. In the thirteenth Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. There are one shorter (2.47 Å) and one longer (2.49 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.87 Å. In the fourteenth Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. The Fe–Fe bond length is 2.48 Å. The Fe–C bond length is 1.87 Å. In the fifteenth Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. The Fe–Fe bond length is 2.47 Å. The Fe–C bond length is 1.87 Å. In the sixteenth Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Sm and ten Fe atoms. The Fe–Fe bond length is 2.50 Å. In the seventeenth Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with nine FeSm3Fe9 cuboctahedra, corners with four CSm2Fe4 octahedra, edges with three FeSm2Fe10 cuboctahedra, edges with two CSm2Fe4 octahedra, and faces with nine FeSm3Fe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 21–29°. In the eighteenth Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with ten FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with four FeSm3Fe9 cuboctahedra, an edgeedge with one CSm2Fe4 octahedra, and faces with twelve FeSm3Fe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 25–30°. There are two inequivalent C sites. In the first C site, C is bonded to two Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with twelve FeSm3Fe9 cuboctahedra, a cornercorner with one CSm2Fe4 octahedra, edges with two FeSm2Fe10 cuboctahedra, and faces with seven FeSm3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 63°. In the second C site, C is bonded to two equivalent Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with ten FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with two equivalent FeSm2Fe10 cuboctahedra, and faces with six FeSm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 63°.

36 MATERIALS SCIENCE↗

Dual active site tandem catalysis of metal hydroxyl oxides and single atoms for boosting oxygen evolution reaction

We report the high voltage in oxygen evolution reaction (OER) often causes structural change in electrocatalysts and forms multiple active sites. Therefore, exploring the synergy of various active sites is extremely significant to develop catalysts for OER with multiple elementary steps. Herein, we adopt the physically adsorbed metal ions method to successfully synthesize a highly-efficient electrocatalyst containing the dual active sites of Fe-NiOOH and NiC4 single atoms (marked as Ni SAs/Fe-NiOOH). The Ni SAs/Fe-NiOOH displays outstanding OER performance with an overpotential of 269 mV to deliver current density of 10 mA/cm 2 that shows 55 mV superior to commercial IrO 2 /CB at the same condition. Experiments and density functional theory calculations indicate that the excellent OER activity of Ni SAs/Fe-NiOOH catalyst is attributed to the synergy of dual active sites of NiC 4 SAs and Fe-NiOOH. A tandem catalysis mechanism is also proposed to reveal the synergism of two active centers, which makes the potential-determining step more facile and accordingly decreases the OER overpotential. This work offers a new concept of tandem catalysis to develop the electrocatalysts with many elemental steps, like OER and oxygen reduction reaction catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Materials Data on Tm4Fe34C3 by Materials Project

Tm4Fe34C3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Tm sites. In the first Tm site, Tm is bonded in a distorted bent 120 degrees geometry to nine Fe and two C atoms. There are a spread of Tm–Fe bond distances ranging from 3.01–3.35 Å. There are one shorter (2.48 Å) and one longer (2.49 Å) Tm–C bond lengths. In the second Tm site, Tm is bonded in a distorted single-bond geometry to fourteen Fe and one C atom. There are a spread of Tm–Fe bond distances ranging from 2.98–3.30 Å. The Tm–C bond length is 2.50 Å. There are eighteen inequivalent Fe sites. In the first Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.45–2.64 Å. The Fe–C bond length is 1.91 Å. In the second Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.46–2.62 Å. The Fe–C bond length is 1.91 Å. In the third Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.46–2.63 Å. The Fe–C bond length is 1.91 Å. In the fourth Fe site, Fe is bonded to three equivalent Tm and nine Fe atoms to form FeTm3Fe9 cuboctahedra that share corners with thirteen FeTm3Fe9 cuboctahedra, corners with two equivalent CTm2Fe4 octahedra, edges with seven FeTm3Fe9 cuboctahedra, faces with ten FeTm3Fe9 cuboctahedra, and a faceface with one CTm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 66–70°. There are a spread of Fe–Fe bond distances ranging from 2.45–2.65 Å. In the fifth Fe site, Fe is bonded to three equivalent Tm and nine Fe atoms to form FeTm3Fe9 cuboctahedra that share corners with ten FeTm3Fe9 cuboctahedra, corners with four CTm2Fe4 octahedra, edges with four FeTm3Fe9 cuboctahedra, faces with five FeTm3Fe9 cuboctahedra, and faces with two CTm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 63–69°. There are a spread of Fe–Fe bond distances ranging from 2.45–2.67 Å. In the sixth Fe site, Fe is bonded to three equivalent Tm and nine Fe atoms to form FeTm3Fe9 cuboctahedra that share corners with thirteen FeTm3Fe9 cuboctahedra, corners with two equivalent CTm2Fe4 octahedra, edges with six FeTm3Fe9 cuboctahedra, faces with ten FeTm3Fe9 cuboctahedra, and a faceface with one CTm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 65–69°. There are a spread of Fe–Fe bond distances ranging from 2.45–2.66 Å. In the seventh Fe site, Fe is bonded in a 2-coordinate geometry to one Tm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.39–2.78 Å. In the eighth Fe site, Fe is bonded in a 2-coordinate geometry to one Tm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.59–2.76 Å. In the ninth Fe site, Fe is bonded to two equivalent Tm and ten Fe atoms to form FeTm2Fe10 cuboctahedra that share corners with eight FeTm3Fe9 cuboctahedra, corners with two equivalent CTm2Fe4 octahedra, edges with two equivalent FeTm3Fe9 cuboctahedra, faces with six FeTm3Fe9 cuboctahedra, and faces with two equivalent CTm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. There are two shorter (2.43 Å) and two longer (2.44 Å) Fe–Fe bond lengths. In the tenth Fe site, Fe is bonded to two equivalent Tm and ten Fe atoms to form FeTm2Fe10 cuboctahedra that share corners with eight FeTm3Fe9 cuboctahedra, corners with two equivalent CTm2Fe4 octahedra, edges with six FeTm3Fe9 cuboctahedra, and faces with ten FeTm3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 44°. There are two shorter (2.42 Å) and two longer (2.43 Å) Fe–Fe bond lengths. In the eleventh Fe site, Fe is bonded to two Tm and ten Fe atoms to form distorted FeTm2Fe10 cuboctahedra that share corners with ten FeTm3Fe9 cuboctahedra, a cornercorner with one CTm2Fe4 octahedra, edges with four FeTm3Fe9 cuboctahedra, faces with eight FeTm3Fe9 cuboctahedra, and faces with two equivalent CTm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. There are a spread of Fe–Fe bond distances ranging from 2.41–2.44 Å. In the twelfth Fe site, Fe is bonded to two Tm and ten Fe atoms to form distorted FeTm2Fe10 cuboctahedra that share corners with thirteen FeTm3Fe9 cuboctahedra, edges with three FeTm3Fe9 cuboctahedra, faces with nine FeTm3Fe9 cuboctahedra, and faces with three CTm2Fe4 octahedra. There are one shorter (2.40 Å) and three longer (2.43 Å) Fe–Fe bond lengths. In the thirteenth Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. The Fe–Fe bond length is 2.47 Å. The Fe–C bond length is 1.85 Å. In the fourteenth Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. There are one shorter (2.46 Å) and one longer (2.47 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.85 Å. In the fifteenth Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. The Fe–Fe bond length is 2.46 Å. The Fe–C bond length is 1.85 Å. In the sixteenth Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Tm and ten Fe atoms. The Fe–Fe bond length is 2.52 Å. In the seventeenth Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Tm and ten Fe atoms. In the eighteenth Fe site, Fe is bonded to two equivalent Tm and ten Fe atoms to form distorted FeTm2Fe10 cuboctahedra that share corners with nine FeTm3Fe9 cuboctahedra, corners with two equivalent CTm2Fe4 octahedra, edges with three FeTm3Fe9 cuboctahedra, an edgeedge with one CTm2Fe4 octahedra, and faces with twelve FeTm3Fe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 25–30°. There are two inequivalent C sites. In the first C site, C is bonded to two Tm and four Fe atoms to form CTm2Fe4 octahedra that share corners with ten FeTm3Fe9 cuboctahedra, a cornercorner with one CTm2Fe4 octahedra, an edgeedge with one FeTm2Fe10 cuboctahedra, and faces with seven FeTm3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 62°. In the second C site, C is bonded to two equivalent Tm and four Fe atoms to form CTm2Fe4 octahedra that share corners with six FeTm3Fe9 cuboctahedra, corners with two equivalent CTm2Fe4 octahedra, and faces with six FeTm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 62°.

36 MATERIALS SCIENCE↗

Materials Data on Gd4Fe34C3 by Materials Project

Gd4Fe34C3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Gd sites. In the first Gd site, Gd is bonded in a distorted bent 120 degrees geometry to nine Fe and two C atoms. There are a spread of Gd–Fe bond distances ranging from 3.03–3.39 Å. Both Gd–C bond lengths are 2.52 Å. In the second Gd site, Gd is bonded in a distorted single-bond geometry to fourteen Fe and one C atom. There are a spread of Gd–Fe bond distances ranging from 3.03–3.34 Å. The Gd–C bond length is 2.54 Å. There are eighteen inequivalent Fe sites. In the first Fe site, Fe is bonded to three equivalent Gd and nine Fe atoms to form distorted FeGd3Fe9 cuboctahedra that share corners with ten FeGd2Fe10 cuboctahedra, corners with four CGd2Fe4 octahedra, edges with four FeGd2Fe10 cuboctahedra, faces with five FeGd2Fe10 cuboctahedra, and faces with two CGd2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 62–69°. There are a spread of Fe–Fe bond distances ranging from 2.46–2.65 Å. In the second Fe site, Fe is bonded to three equivalent Gd and nine Fe atoms to form FeGd3Fe9 cuboctahedra that share corners with thirteen FeGd2Fe10 cuboctahedra, corners with two equivalent CGd2Fe4 octahedra, edges with six FeGd2Fe10 cuboctahedra, faces with ten FeGd2Fe10 cuboctahedra, and a faceface with one CGd2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 65–70°. There are a spread of Fe–Fe bond distances ranging from 2.46–2.66 Å. In the third Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.46–2.64 Å. The Fe–C bond length is 1.90 Å. In the fourth Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.47–2.65 Å. The Fe–C bond length is 1.90 Å. In the fifth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.46–2.63 Å. The Fe–C bond length is 1.90 Å. In the sixth Fe site, Fe is bonded to three equivalent Gd and nine Fe atoms to form FeGd3Fe9 cuboctahedra that share corners with thirteen FeGd2Fe10 cuboctahedra, corners with two equivalent CGd2Fe4 octahedra, edges with seven FeGd2Fe10 cuboctahedra, faces with ten FeGd2Fe10 cuboctahedra, and a faceface with one CGd2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 66–70°. There are a spread of Fe–Fe bond distances ranging from 2.47–2.68 Å. In the seventh Fe site, Fe is bonded in a 2-coordinate geometry to one Gd and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.39–2.74 Å. In the eighth Fe site, Fe is bonded in a 2-coordinate geometry to one Gd and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.62–2.74 Å. In the ninth Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.41–2.46 Å. The Fe–C bond length is 1.85 Å. In the tenth Fe site, Fe is bonded in a single-bond geometry to seven Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.43–2.46 Å. The Fe–C bond length is 1.85 Å. In the eleventh Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. There are two shorter (2.43 Å) and one longer (2.46 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.85 Å. In the twelfth Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Gd and ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.41–2.47 Å. In the thirteenth Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Gd and ten Fe atoms. Both Fe–Fe bond lengths are 2.42 Å. In the fourteenth Fe site, Fe is bonded to two equivalent Gd and ten Fe atoms to form distorted FeGd2Fe10 cuboctahedra that share corners with nine FeGd2Fe10 cuboctahedra, corners with two equivalent CGd2Fe4 octahedra, edges with three FeGd2Fe10 cuboctahedra, an edgeedge with one CGd2Fe4 octahedra, and faces with twelve FeGd2Fe10 cuboctahedra. The corner-sharing octahedra tilt angles range from 25–30°. There are one shorter (2.42 Å) and one longer (2.43 Å) Fe–Fe bond lengths. In the fifteenth Fe site, Fe is bonded to two equivalent Gd and ten Fe atoms to form FeGd2Fe10 cuboctahedra that share corners with eight FeGd2Fe10 cuboctahedra, corners with two equivalent CGd2Fe4 octahedra, edges with two equivalent FeGd3Fe9 cuboctahedra, faces with six FeGd2Fe10 cuboctahedra, and faces with two equivalent CGd2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. In the sixteenth Fe site, Fe is bonded to two equivalent Gd and ten Fe atoms to form FeGd2Fe10 cuboctahedra that share corners with eight FeGd2Fe10 cuboctahedra, corners with two equivalent CGd2Fe4 octahedra, edges with six FeGd3Fe9 cuboctahedra, and faces with ten FeGd2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 45°. In the seventeenth Fe site, Fe is bonded to two Gd and ten Fe atoms to form distorted FeGd2Fe10 cuboctahedra that share corners with ten FeGd2Fe10 cuboctahedra, a cornercorner with one CGd2Fe4 octahedra, edges with four FeGd3Fe9 cuboctahedra, faces with eight FeGd2Fe10 cuboctahedra, and faces with two equivalent CGd2Fe4 octahedra. The corner-sharing octahedral tilt angles are 45°. In the eighteenth Fe site, Fe is bonded to two Gd and ten Fe atoms to form distorted FeGd2Fe10 cuboctahedra that share corners with thirteen FeGd2Fe10 cuboctahedra, edges with three FeGd3Fe9 cuboctahedra, faces with nine FeGd2Fe10 cuboctahedra, and faces with three CGd2Fe4 octahedra. There are two inequivalent C sites. In the first C site, C is bonded to two Gd and four Fe atoms to form CGd2Fe4 octahedra that share corners with ten FeGd2Fe10 cuboctahedra, a cornercorner with one CGd2Fe4 octahedra, an edgeedge with one FeGd2Fe10 cuboctahedra, and faces with seven FeGd2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 63°. In the second C site, C is bonded to two equivalent Gd and four Fe atoms to form CGd2Fe4 octahedra that share corners with six FeGd2Fe10 cuboctahedra, corners with two equivalent CGd2Fe4 octahedra, and faces with six FeGd2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 63°.

36 MATERIALS SCIENCE↗

Materials Data on Sm4TiFe33N4 by Materials Project

Sm4TiFe33N4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Sm sites. In the first Sm site, Sm is bonded in a distorted bent 120 degrees geometry to eight Fe and two N atoms. There are a spread of Sm–Fe bond distances ranging from 3.09–3.38 Å. There are one shorter (2.50 Å) and one longer (2.51 Å) Sm–N bond lengths. In the second Sm site, Sm is bonded in a bent 120 degrees geometry to nine Fe and two N atoms. There are a spread of Sm–Fe bond distances ranging from 3.08–3.38 Å. Both Sm–N bond lengths are 2.50 Å. In the third Sm site, Sm is bonded in a bent 120 degrees geometry to nine Fe and two N atoms. There are a spread of Sm–Fe bond distances ranging from 3.09–3.38 Å. Both Sm–N bond lengths are 2.50 Å. In the fourth Sm site, Sm is bonded in a distorted bent 120 degrees geometry to one Ti, eight Fe, and two N atoms. The Sm–Ti bond length is 3.19 Å. There are a spread of Sm–Fe bond distances ranging from 3.10–3.41 Å. Both Sm–N bond lengths are 2.51 Å. Ti is bonded in a 1-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Ti–Fe bond distances ranging from 2.37–2.78 Å. There are thirty-three inequivalent Fe sites. In the first Fe site, Fe is bonded in a single-bond geometry to six Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.45–2.75 Å. The Fe–N bond length is 1.89 Å. In the second Fe site, Fe is bonded in a single-bond geometry to one Ti, four Fe, and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.43–2.59 Å. The Fe–N bond length is 1.88 Å. In the third Fe site, Fe is bonded in a single-bond geometry to six Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.45–2.74 Å. The Fe–N bond length is 1.88 Å. In the fourth Fe site, Fe is bonded in a single-bond geometry to one Ti, four Fe, and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.61 Å. The Fe–N bond length is 1.90 Å. In the fifth Fe site, Fe is bonded to two Sm, one Ti, and nine Fe atoms to form distorted FeSm2TiFe9 cuboctahedra that share corners with seven FeSm2Fe10 cuboctahedra, corners with four NSm2Fe4 octahedra, edges with two FeSm2Fe10 cuboctahedra, edges with two NSm2Fe4 octahedra, and faces with nine FeSm2TiFe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 24–29°. There are a spread of Fe–Fe bond distances ranging from 2.46–2.78 Å. In the sixth Fe site, Fe is bonded to two Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with seven FeSm2Fe10 cuboctahedra, corners with four NSm2Fe4 octahedra, edges with three FeSm2Fe10 cuboctahedra, edges with two NSm2Fe4 octahedra, and faces with eight FeSm2Fe10 cuboctahedra. The corner-sharing octahedra tilt angles range from 24–28°. There are a spread of Fe–Fe bond distances ranging from 2.45–2.78 Å. In the seventh Fe site, Fe is bonded in a single-bond geometry to one Ti, four Fe, and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.57 Å. The Fe–N bond length is 1.90 Å. In the eighth Fe site, Fe is bonded in a single-bond geometry to six Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.74 Å. The Fe–N bond length is 1.88 Å. In the ninth Fe site, Fe is bonded to two Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with eight FeSm2Fe10 cuboctahedra, corners with four NSm2Fe4 octahedra, edges with three FeSm2Fe10 cuboctahedra, edges with two NSm2Fe4 octahedra, and faces with nine FeSm2Fe10 cuboctahedra. The corner-sharing octahedra tilt angles range from 24–28°. There are a spread of Fe–Fe bond distances ranging from 2.46–2.76 Å. In the tenth Fe site, Fe is bonded in a 12-coordinate geometry to two Sm, one Ti, and nine Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.45–2.81 Å. In the eleventh Fe site, Fe is bonded in a single-bond geometry to six Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.45–2.75 Å. The Fe–N bond length is 1.89 Å. In the twelfth Fe site, Fe is bonded in a single-bond geometry to one Ti, four Fe, and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.43–2.62 Å. The Fe–N bond length is 1.88 Å. In the thirteenth Fe site, Fe is bonded in a single-bond geometry to one Ti, four Fe, and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.50–2.56 Å. The Fe–N bond length is 1.93 Å. In the fourteenth Fe site, Fe is bonded in a single-bond geometry to five Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.47–2.66 Å. The Fe–N bond length is 1.92 Å. In the fifteenth Fe site, Fe is bonded in a single-bond geometry to five Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.49–2.66 Å. The Fe–N bond length is 1.93 Å. In the sixteenth Fe site, Fe is bonded in a single-bond geometry to one Ti, four Fe, and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.50–2.56 Å. The Fe–N bond length is 1.92 Å. In the seventeenth Fe site, Fe is bonded to three Sm and nine Fe atoms to form FeSm3Fe9 cuboctahedra that share corners with eleven FeSm2TiFe9 cuboctahedra, corners with four NSm2Fe4 octahedra, edges with four FeSm2Fe10 cuboctahedra, faces with eight FeSm2Fe10 cuboctahedra, and faces with two NSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 64–69°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.68 Å. In the eighteenth Fe site, Fe is bonded to three Sm, one Ti, and eight Fe atoms to form FeSm3TiFe8 cuboctahedra that share corners with ten FeSm2Fe10 cuboctahedra, corners with four NSm2Fe4 octahedra, edges with four FeSm2Fe10 cuboctahedra, faces with six FeSm2TiFe9 cuboctahedra, and faces with two NSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 64–70°. There are a spread of Fe–Fe bond distances ranging from 2.49–2.55 Å. In the nineteenth Fe site, Fe is bonded in a single-bond geometry to five Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.48–2.65 Å. The Fe–N bond length is 1.92 Å. In the twentieth Fe site, Fe is bonded in a single-bond geometry to four Fe and one N atom. There are one shorter (2.46 Å) and one longer (2.48 Å) Fe–Fe bond lengths. The Fe–N bond length is 1.92 Å. In the twenty-first Fe site, Fe is bonded in a single-bond geometry to four Fe and one N atom. There are one shorter (2.48 Å) and one longer (2.49 Å) Fe–Fe bond lengths. The Fe–N bond length is 1.92 Å. In the twenty-second Fe site, Fe is bonded in a single-bond geometry to five Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.47–2.66 Å. The Fe–N bond length is 1.92 Å. In the twenty-third Fe site, Fe is bonded to three Sm and nine Fe atoms to form FeSm3Fe9 cuboctahedra that share corners with eleven FeSm2TiFe9 cuboctahedra, corners with four NSm2Fe4 octahedra, edges with four FeSm2Fe10 cuboctahedra, faces with seven FeSm2TiFe9 cuboctahedra, and faces with two NSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 64–69°. There are a spread of Fe–Fe bond distances ranging from 2.47–2.69 Å. In the twenty-fourth Fe site, Fe is bonded to three Sm and nine Fe atoms to form FeSm3Fe9 cuboctahedra that share corners with ten FeSm2Fe10 cuboctahedra, corners with four NSm2Fe4 octahedra, edges with four FeSm2Fe10 cuboctahedra, faces with seven FeSm2Fe10 cuboctahedra, and faces with two NSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 62–68°. There are a spread of Fe–Fe bond distances ranging from 2.47–2.69 Å. In the twenty-fifth Fe site, Fe is bonded to two Sm and ten Fe atoms to form FeSm2Fe10 cuboctahedra that share corners with seven FeSm2Fe10 cuboctahedra, corners with two NSm2Fe4 octahedra, edges with four FeSm2TiFe9 cuboctahedra, faces with eight FeSm2Fe10 cuboctahedra, and faces with two equivalent NSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. There are one shorter (2.64 Å) and one longer (2.66 Å) Fe–Fe bond lengths. In the twenty-sixth Fe site, Fe is bonded to two Sm, one Ti, and nine Fe atoms to form distorted FeSm2TiFe9 cuboctahedra that share corners with eight FeSm2Fe10 cuboctahedra, corners with two NSm2Fe4 octahedra, edges with three FeSm2Fe10 cuboctahedra, faces with seven FeSm2Fe10 cuboctahedra, and faces with two equivalent NSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 44–46°. The Fe–Fe bond length is 2.65 Å. In the twenty-seventh Fe site, Fe is bonded to two Sm, one Ti, and nine Fe atoms to form distorted FeSm2TiFe9 cuboctahedra that share corners with seven FeSm2TiFe9 cuboctahedra, corners with two NSm2Fe4 octahedra, edges with four FeSm2Fe10 cuboctahedra, faces with seven FeSm2TiFe9 cuboctahedra, and faces with two equivalent NSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 44–46°. The Fe–Fe bond length is 2.63 Å. In the twenty-eighth Fe site, Fe is bonded to two Sm and ten Fe atoms to form FeSm2Fe10 cuboctahedra that share corners with eight FeSm2Fe10 cuboctahedra, corners with two NSm2Fe4 octahedra, edges with three FeSm2TiFe9 cuboctahedra, faces with eight FeSm2Fe10 cuboctahedra, and faces with two equivalent NSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. Both Fe–Fe bond lengths are 2.65 Å. In the twenty-ninth Fe site, Fe is bonded to two Sm and ten Fe atoms to form FeSm2Fe10 cuboctahedra that share corners with thirteen FeSm2TiFe9 cuboctahedra, edges with two FeSm3Fe9 cuboctahedra, faces with ten FeSm2Fe10 cuboctahedra, and faces with four NSm2Fe4 octahedra. There are one shorter (2.68 Å) and one longer (2.69 Å) Fe–Fe bond lengths. In the thirtieth Fe site, Fe is bonded to two Sm, one Ti, and nine Fe atoms to form distorted FeSm2TiFe9 cuboctahedra that share corners with thirteen FeSm2TiFe9 cuboctahedra, edges with two FeSm3Fe9 cuboctahedra, faces with eight FeSm2TiFe9 cuboctahedra, and faces with four NSm2Fe4 octahedra. The Fe–Fe bond length is 2.66 Å. In the thirty-first Fe site, Fe is bonded in a distorted single-bond geometry to one Ti and six Fe atoms. In the thirty-second Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. The Fe–Fe bond length is 2.38 Å. In the thirty-third Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. There are four inequivalent N sites. In the first N site, N is bonded to two Sm and four Fe atoms to form NSm2Fe4 octahedra that share corners with nine FeSm2Fe10 cuboctahedra, corners with two NSm2Fe4 octahedra, edges with two FeSm2Fe10 cuboctahedra, and faces with six FeSm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 61°. In the second N site, N is bonded to two Sm and four Fe atoms to form NSm2Fe4 octahedra that share corners with nine FeSm2TiFe9 cuboctahedra, corners with two NSm2Fe4 octahedra, an edgeedge with one FeSm2TiFe9 cuboctahedra, and faces with six FeSm2TiFe9 cuboctahedra. The corner-sharing octahedral tilt angles are 61°. In the third N site, N is bonded to two Sm and four Fe atoms to form NSm2Fe4 octahedra that share corners with ten FeSm2Fe10 cuboctahedra, corners with two NSm2Fe4 octahedra, edges with two FeSm2TiFe9 cuboctahedra, and faces with six FeSm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 61°. In the fourth N site, N is bonded to two Sm and four Fe atoms to form NSm2Fe4 octahedra that share corners with eight FeSm2Fe10 cuboctahedra, corners with two NSm2Fe4 octahedra, an edgeedge with one FeSm2Fe10 cuboctahedra, and faces with six FeSm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 61°.

36 MATERIALS SCIENCE↗

Materials Data on Th3Fe33C4 by Materials Project

Th3Fe33C4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Th sites. In the first Th site, Th is bonded in a distorted L-shaped geometry to ten Fe and two C atoms. There are a spread of Th–Fe bond distances ranging from 3.11–3.28 Å. There are one shorter (2.68 Å) and one longer (2.70 Å) Th–C bond lengths. In the second Th site, Th is bonded in a distorted T-shaped geometry to six Fe and three C atoms. There are a spread of Th–Fe bond distances ranging from 3.14–3.29 Å. There are a spread of Th–C bond distances ranging from 2.66–2.69 Å. In the third Th site, Th is bonded in a distorted T-shaped geometry to six Fe and three C atoms. There are a spread of Th–Fe bond distances ranging from 3.14–3.29 Å. There are two shorter (2.66 Å) and one longer (2.69 Å) Th–C bond lengths. There are thirty-five inequivalent Fe sites. In the first Fe site, Fe is bonded in a 12-coordinate geometry to ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.41–2.66 Å. In the second Fe site, Fe is bonded in a 12-coordinate geometry to ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.41–2.66 Å. In the third Fe site, Fe is bonded in a 12-coordinate geometry to ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.41–2.64 Å. In the fourth Fe site, Fe is bonded in a 12-coordinate geometry to ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.42–2.65 Å. In the fifth Fe site, Fe is bonded in a 12-coordinate geometry to ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.42–2.67 Å. In the sixth Fe site, Fe is bonded in a 12-coordinate geometry to ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.42–2.65 Å. In the seventh Fe site, Fe is bonded in a 12-coordinate geometry to ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.43–2.69 Å. In the eighth Fe site, Fe is bonded in a 12-coordinate geometry to ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.44–2.70 Å. In the ninth Fe site, Fe is bonded to two Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with four FeTh2Fe10 cuboctahedra, corners with five CTh2Fe4 octahedra, faces with nine FeTh2Fe10 cuboctahedra, and a faceface with one CTh2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 24–71°. There are a spread of Fe–Fe bond distances ranging from 2.50–2.67 Å. In the tenth Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with two FeTh2Fe10 cuboctahedra, corners with six CTh2Fe4 octahedra, an edgeedge with one CTh2Fe4 octahedra, faces with four FeTh2Fe10 cuboctahedra, and a faceface with one CTh2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 24–70°. There are a spread of Fe–Fe bond distances ranging from 2.47–2.69 Å. In the eleventh Fe site, Fe is bonded to two Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with four FeTh2Fe10 cuboctahedra, corners with five CTh2Fe4 octahedra, an edgeedge with one FeTh2Fe10 cuboctahedra, an edgeedge with one CTh2Fe4 octahedra, faces with five FeTh2Fe10 cuboctahedra, and a faceface with one CTh2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 26–64°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.70 Å. In the twelfth Fe site, Fe is bonded to two Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with three FeTh2Fe10 cuboctahedra, corners with six CTh2Fe4 octahedra, edges with two FeTh2Fe10 cuboctahedra, an edgeedge with one CTh2Fe4 octahedra, and faces with six FeTh2Fe10 cuboctahedra. The corner-sharing octahedra tilt angles range from 23–70°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.72 Å. In the thirteenth Fe site, Fe is bonded to two Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with six FeTh2Fe10 cuboctahedra, corners with five CTh2Fe4 octahedra, an edgeedge with one FeTh2Fe10 cuboctahedra, an edgeedge with one CTh2Fe4 octahedra, faces with five FeTh2Fe10 cuboctahedra, and a faceface with one CTh2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 24–71°. There are a spread of Fe–Fe bond distances ranging from 2.47–2.71 Å. In the fourteenth Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with two equivalent FeTh2Fe10 cuboctahedra, corners with six CTh2Fe4 octahedra, an edgeedge with one CTh2Fe4 octahedra, faces with four FeTh2Fe10 cuboctahedra, and a faceface with one CTh2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 24–71°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.69 Å. In the fifteenth Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with five FeTh2Fe10 cuboctahedra, corners with four CTh2Fe4 octahedra, an edgeedge with one FeTh2Fe10 cuboctahedra, faces with ten FeTh2Fe10 cuboctahedra, and a faceface with one CTh2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 26–65°. There are a spread of Fe–Fe bond distances ranging from 2.51–2.66 Å. In the sixteenth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. The Fe–Fe bond length is 2.67 Å. The Fe–C bond length is 1.87 Å. In the seventeenth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. The Fe–Fe bond length is 2.67 Å. The Fe–C bond length is 1.88 Å. In the eighteenth Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. The Fe–Fe bond length is 2.69 Å. The Fe–C bond length is 1.89 Å. In the nineteenth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. The Fe–Fe bond length is 2.68 Å. The Fe–C bond length is 1.88 Å. In the twentieth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. The Fe–Fe bond length is 2.68 Å. The Fe–C bond length is 1.88 Å. In the twenty-first Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. There are one shorter (2.65 Å) and one longer (2.70 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.89 Å. In the twenty-second Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–Fe bond length is 2.72 Å. The Fe–C bond length is 1.87 Å. In the twenty-third Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–Fe bond length is 2.72 Å. The Fe–C bond length is 1.87 Å. In the twenty-fourth Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. There are one shorter (2.48 Å) and one longer (2.76 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.86 Å. In the twenty-fifth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–Fe bond length is 2.71 Å. The Fe–C bond length is 1.87 Å. In the twenty-sixth Fe site, Fe is bonded in a single-bond geometry to four Fe and one C atom. The Fe–Fe bond length is 2.72 Å. The Fe–C bond length is 1.87 Å. In the twenty-seventh Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form distorted FeTh2Fe10 cuboctahedra that share corners with seven FeTh2Fe10 cuboctahedra, corners with five CTh2Fe4 octahedra, edges with three FeTh2Fe10 cuboctahedra, an edgeedge with one CTh2Fe4 octahedra, and faces with seven FeTh2Fe10 cuboctahedra. The corner-sharing octahedra tilt angles range from 24–70°. There are one shorter (2.65 Å) and one longer (2.73 Å) Fe–Fe bond lengths. In the twenty-eighth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. The Fe–Fe bond length is 2.75 Å. The Fe–C bond length is 1.86 Å. In the twenty-ninth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. The Fe–Fe bond length is 2.75 Å. The Fe–C bond length is 1.86 Å. In the thirtieth Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. The Fe–Fe bond length is 2.75 Å. The Fe–C bond length is 1.86 Å. In the thirty-first Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. The Fe–Fe bond length is 2.74 Å. The Fe–C bond length is 1.86 Å. In the thirty-second Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. The Fe–Fe bond length is 2.75 Å. The Fe–C bond length is 1.86 Å. In the thirty-third Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Th and twelve Fe atoms. In the thirty-fourth Fe site, Fe is bonded in a 1-coordinate geometry to two equivalent Th and twelve Fe atoms. In the thirty-fifth Fe site, Fe is bonded in a 1-coordinate geometry to two equivalent Th and twelve Fe atoms. There are five inequivalent C sites. In the first C site, C is bonded to two Th and four Fe atoms to form distorted CTh2Fe4 octahedra that share corners with six FeTh2Fe10 cuboctahedra, corners with four CTh2Fe4 octahedra, edges with two FeTh2Fe10 cuboctahedra, and faces with two FeTh2Fe10 cuboctahedra. The corner-sharing octahedra tilt angles range from 36–85°. In the second C site, C is bonded to two Th and four Fe atoms to form distorted CTh2Fe4 octahedra that share corners with twelve FeTh2Fe10 cuboctahedra, corners with three CTh2Fe4 octahedra, edges with two FeTh2Fe10 cuboctahedra, and faces with two FeTh2Fe10 cuboctahedra. The corner-sharing octahedra tilt angles range from 36–86°. In the third C site, C is bonded to two equivalent Th and four Fe atoms to form distorted CTh2Fe4 octahedra that share corners with six FeTh2Fe10 cuboctahedra, corners with four CTh2Fe4 octahedra, edges with two equivalent FeTh2Fe10 cuboctahedra, and faces with two equivalent FeTh2Fe10 cuboctahedra. The corner-sharing octahedra tilt angles range from 36–85°. In the fourth C site, C is bonded to two equivalent Th and four Fe atoms to form distorted CTh2Fe4 octahedra that share corners with eighteen FeTh2Fe10 cuboctahedra, corners with two equivalent CTh2Fe4 octahedra, edges with two equivalent FeTh2Fe10 cuboctahedra, and faces with two equivalent FeTh2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 86°. In the fifth C site, C is bonded to two Th and four Fe atoms to form distorted CTh2Fe4 octahedra that share corners with twelve FeTh2Fe10 cuboctahedra and corners with four CTh2Fe4 octahedra. The corner-sharing octahedral tilt angles are 85°.

36 MATERIALS SCIENCE↗

Self-Sacrificial Template Synthesis of Fe-N-C Catalysts with Dense Active Sites Deposited on A Porous Carbon Network for High Performance in PEMFC

In this study, iron-nitrogen-carbon (Fe-N-C) single-atom catalysts are promising sustainable alternatives to the costly and scarce platinum (Pt) to catalyze the oxygen reduction reactions (ORR) at the cathode of proton exchange membrane fuel cells (PEMFCs). However, Fe-N-C cathodes for PEMFC are made thicker than Pt/C ones, in order to compensate for the lower intrinsic ORR activity and site density of Fe-N-C materials. The thick electrodes are bound with mass transport issues that limit their performance at high current densities, especially in H 2 /air PEMFCs. Practical Fe-N-C electrodes must combine high intrinsic ORR activity, high site density, and fast mass transport. Herein, it has achieved an improved combination of these properties with a Fe-N-C catalyst prepared via a two-step synthesis approach, constructing first a porous zinc-nitrogen-carbon (Zn-N-C) substrate, followed by transmetallating Zn by Fe via chemical vapor deposition. A cathode comprising this Fe-N-C catalyst has exhibited a maximum power density of 0.53 W cm -2 in H 2 /air PEMFC at 80 °C. The improved power density is associated with the hierarchical porosity of the Zn-N-C substrate of this work, which is achieved by epitaxial growth of ZIF-8 onto g-C 3 N 4 , leading to a micro-mesoporous substrate.

25 ENERGY STORAGE↗

Materials Data on Fe11Mo6C5 by Materials Project

Mo6Fe11C5 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Mo sites. In the first Mo site, Mo is bonded in a 2-coordinate geometry to one Fe and three C atoms. The Mo–Fe bond length is 2.71 Å. There are a spread of Mo–C bond distances ranging from 2.08–2.38 Å. In the second Mo site, Mo is bonded in a 2-coordinate geometry to one Fe and two equivalent C atoms. The Mo–Fe bond length is 2.78 Å. Both Mo–C bond lengths are 2.20 Å. There are five inequivalent Fe sites. In the first Fe site, Fe is bonded in a distorted water-like geometry to one Fe and two equivalent C atoms. The Fe–Fe bond length is 2.48 Å. There are one shorter (1.99 Å) and one longer (2.09 Å) Fe–C bond lengths. In the second Fe site, Fe is bonded in a distorted bent 150 degrees geometry to one Fe and two equivalent C atoms. The Fe–Fe bond length is 2.49 Å. Both Fe–C bond lengths are 1.94 Å. In the third Fe site, Fe is bonded in a single-bond geometry to one C atom. The Fe–C bond length is 1.93 Å. In the fourth Fe site, Fe is bonded in a bent 150 degrees geometry to two equivalent C atoms. Both Fe–C bond lengths are 1.98 Å. In the fifth Fe site, Fe is bonded to six Mo and six Fe atoms to form FeFe6Mo6 cuboctahedra that share edges with two equivalent CFe2Mo4 octahedra. There are two inequivalent C sites. In the first C site, C is bonded in a 7-coordinate geometry to three Mo and four Fe atoms. In the second C site, C is bonded to four equivalent Mo and two equivalent Fe atoms to form CFe2Mo4 octahedra that share edges with two equivalent FeFe6Mo6 cuboctahedra.

36 MATERIALS SCIENCE↗

Materials Data on Dy2Fe17CN by Materials Project

Dy2Fe17CN crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Dy is bonded in a distorted bent 120 degrees geometry to nine Fe, one C, and one N atom. There are a spread of Dy–Fe bond distances ranging from 3.04–3.34 Å. The Dy–C bond length is 2.52 Å. The Dy–N bond length is 2.44 Å. There are ten inequivalent Fe sites. In the first Fe site, Fe is bonded in a 2-coordinate geometry to one Dy and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.39–2.77 Å. In the second Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.47–2.59 Å. The Fe–C bond length is 1.91 Å. In the third Fe site, Fe is bonded in a single-bond geometry to five Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.47–2.56 Å. The Fe–N bond length is 1.92 Å. In the fourth Fe site, Fe is bonded to three equivalent Dy and nine Fe atoms to form FeDy3Fe9 cuboctahedra that share corners with eleven FeDy3Fe9 cuboctahedra, corners with two equivalent CDy2Fe4 octahedra, corners with two equivalent NDy2Fe4 octahedra, edges with four FeDy3Fe9 cuboctahedra, faces with eight FeDy3Fe9 cuboctahedra, a faceface with one CDy2Fe4 octahedra, and a faceface with one NDy2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 63–70°. There are a spread of Fe–Fe bond distances ranging from 2.45–2.60 Å. In the fifth Fe site, Fe is bonded to two equivalent Dy and ten Fe atoms to form FeDy2Fe10 cuboctahedra that share corners with eight FeDy3Fe9 cuboctahedra, corners with two equivalent CDy2Fe4 octahedra, edges with four FeDy3Fe9 cuboctahedra, faces with eight FeDy3Fe9 cuboctahedra, and faces with two equivalent NDy2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. There are two shorter (2.43 Å) and two longer (2.45 Å) Fe–Fe bond lengths. In the sixth Fe site, Fe is bonded to two equivalent Dy and ten Fe atoms to form distorted FeDy2Fe10 cuboctahedra that share corners with eight FeDy3Fe9 cuboctahedra, corners with two equivalent NDy2Fe4 octahedra, edges with four FeDy2Fe10 cuboctahedra, faces with eight FeDy3Fe9 cuboctahedra, and faces with two equivalent CDy2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. There are two shorter (2.43 Å) and two longer (2.44 Å) Fe–Fe bond lengths. In the seventh Fe site, Fe is bonded to two equivalent Dy and ten Fe atoms to form distorted FeDy2Fe10 cuboctahedra that share corners with fourteen FeDy3Fe9 cuboctahedra, edges with two equivalent FeDy3Fe9 cuboctahedra, faces with ten FeDy3Fe9 cuboctahedra, faces with two equivalent CDy2Fe4 octahedra, and faces with two equivalent NDy2Fe4 octahedra. There are two shorter (2.43 Å) and two longer (2.44 Å) Fe–Fe bond lengths. In the eighth Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. The Fe–Fe bond length is 2.47 Å. The Fe–C bond length is 1.85 Å. In the ninth Fe site, Fe is bonded in a single-bond geometry to six Fe and one N atom. The Fe–Fe bond length is 2.49 Å. The Fe–N bond length is 1.89 Å. In the tenth Fe site, Fe is bonded to two equivalent Dy and ten Fe atoms to form distorted FeDy2Fe10 cuboctahedra that share corners with eight FeDy3Fe9 cuboctahedra, corners with two equivalent CDy2Fe4 octahedra, corners with two equivalent NDy2Fe4 octahedra, edges with three FeDy2Fe10 cuboctahedra, an edgeedge with one CDy2Fe4 octahedra, an edgeedge with one NDy2Fe4 octahedra, and faces with nine FeDy3Fe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 23–29°. C is bonded to two equivalent Dy and four Fe atoms to form CDy2Fe4 octahedra that share corners with ten FeDy3Fe9 cuboctahedra, corners with two equivalent NDy2Fe4 octahedra, edges with two equivalent FeDy2Fe10 cuboctahedra, and faces with six FeDy2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 62°. N is bonded to two equivalent Dy and four Fe atoms to form NDy2Fe4 octahedra that share corners with ten FeDy3Fe9 cuboctahedra, corners with two equivalent CDy2Fe4 octahedra, edges with two equivalent FeDy2Fe10 cuboctahedra, and faces with six FeDy2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 62°.

36 MATERIALS SCIENCE↗

Materials Data on FeO2 by Materials Project

FeO2 is Cyanogen Chloride-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is zero-dimensional and consists of two iron dihydroxide molecules. Fe is bonded in a linear geometry to two equivalent O atoms. Both Fe–O bond lengths are 1.59 Å. O is bonded in a single-bond geometry to one Fe atom.

36 MATERIALS SCIENCE↗

Materials Data on FeO2 by Materials Project

FeO2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four iron dihydroxide molecules. Fe is bonded in a distorted linear geometry to two equivalent O atoms. Both Fe–O bond lengths are 1.32 Å. O is bonded in a single-bond geometry to one Fe atom.

36 MATERIALS SCIENCE↗

Materials Data on SmErFe17C2 by Materials Project

ErSmFe17C2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Er is bonded in a distorted bent 120 degrees geometry to nine Fe and two equivalent C atoms. There are a spread of Er–Fe bond distances ranging from 3.02–3.39 Å. Both Er–C bond lengths are 2.48 Å. Sm is bonded in a distorted bent 120 degrees geometry to nine Fe and two equivalent C atoms. There are a spread of Sm–Fe bond distances ranging from 3.04–3.36 Å. Both Sm–C bond lengths are 2.56 Å. There are eleven inequivalent Fe sites. In the first Fe site, Fe is bonded in a 2-coordinate geometry to one Er and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.38–2.77 Å. In the second Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.65–2.77 Å. In the third Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.56 Å. The Fe–C bond length is 1.86 Å. In the fourth Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.43–2.57 Å. The Fe–C bond length is 1.86 Å. In the fifth Fe site, Fe is bonded in a 12-coordinate geometry to one Er, one Sm, and ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.45–2.63 Å. In the sixth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are two shorter (2.48 Å) and one longer (2.53 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.91 Å. In the seventh Fe site, Fe is bonded to one Er, two equivalent Sm, and nine Fe atoms to form FeSm2ErFe9 cuboctahedra that share corners with nine FeSm2ErFe9 cuboctahedra, corners with four equivalent CSmErFe4 octahedra, edges with four FeSmEr2Fe9 cuboctahedra, faces with four FeSmEr2Fe9 cuboctahedra, and faces with two equivalent CSmErFe4 octahedra. The corner-sharing octahedra tilt angles range from 64–68°. There are two shorter (2.48 Å) and two longer (2.53 Å) Fe–Fe bond lengths. In the eighth Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. Both Fe–Fe bond lengths are 2.47 Å. The Fe–C bond length is 1.92 Å. In the ninth Fe site, Fe is bonded to two equivalent Er, one Sm, and nine Fe atoms to form distorted FeSmEr2Fe9 cuboctahedra that share corners with nine FeSm2ErFe9 cuboctahedra, corners with four equivalent CSmErFe4 octahedra, edges with four FeSm2ErFe9 cuboctahedra, faces with four FeSm2ErFe9 cuboctahedra, and faces with two equivalent CSmErFe4 octahedra. The corner-sharing octahedra tilt angles range from 64–68°. Both Fe–Fe bond lengths are 2.46 Å. In the tenth Fe site, Fe is bonded to one Er, one Sm, and ten Fe atoms to form FeSmErFe10 cuboctahedra that share corners with six FeSm2ErFe9 cuboctahedra, corners with two equivalent CSmErFe4 octahedra, edges with two FeSm2ErFe9 cuboctahedra, faces with six FeSm2ErFe9 cuboctahedra, and faces with two equivalent CSmErFe4 octahedra. The corner-sharing octahedra tilt angles range from 43–44°. In the eleventh Fe site, Fe is bonded to one Er, one Sm, and ten Fe atoms to form distorted FeSmErFe10 cuboctahedra that share corners with ten FeSm2ErFe9 cuboctahedra, edges with two FeSmEr2Fe9 cuboctahedra, faces with six FeSm2ErFe9 cuboctahedra, and faces with four equivalent CSmErFe4 octahedra. C is bonded to one Er, one Sm, and four Fe atoms to form CSmErFe4 octahedra that share corners with six FeSm2ErFe9 cuboctahedra, corners with two equivalent CSmErFe4 octahedra, and faces with six FeSmEr2Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 63°.

36 MATERIALS SCIENCE↗

Materials Data on Mg14FeCo by Materials Project

Mg14FeCo crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are seven inequivalent Mg sites. In the first Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with four equivalent CoMg10Fe2 cuboctahedra, corners with fourteen MgMg12 cuboctahedra, edges with six MgMg12 cuboctahedra, faces with two equivalent FeMg10Co2 cuboctahedra, and faces with six MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.07–3.22 Å. In the second Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with four equivalent FeMg10Co2 cuboctahedra, corners with fourteen MgMg12 cuboctahedra, edges with six MgMg12 cuboctahedra, faces with two equivalent CoMg10Fe2 cuboctahedra, and faces with six MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.07–3.22 Å. In the third Mg site, Mg is bonded to eight Mg, two equivalent Fe, and two equivalent Co atoms to form distorted MgMg8Fe2Co2 cuboctahedra that share corners with eighteen MgMg12 cuboctahedra, edges with two equivalent MgMg8Fe2Co2 cuboctahedra, edges with two equivalent FeMg10Co2 cuboctahedra, edges with two equivalent CoMg10Fe2 cuboctahedra, faces with two equivalent FeMg10Co2 cuboctahedra, faces with two equivalent CoMg10Fe2 cuboctahedra, and faces with four MgMg8Fe2Co2 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 2.89–3.14 Å. There are one shorter (3.01 Å) and one longer (3.22 Å) Mg–Fe bond lengths. There are one shorter (3.02 Å) and one longer (3.22 Å) Mg–Co bond lengths. In the fourth Mg site, Mg is bonded to twelve Mg atoms to form MgMg12 cuboctahedra that share corners with four equivalent FeMg10Co2 cuboctahedra, corners with four equivalent CoMg10Fe2 cuboctahedra, corners with ten MgMg8Fe2Co2 cuboctahedra, edges with six MgMg12 cuboctahedra, and faces with eight MgMg12 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.12–3.29 Å. In the fifth Mg site, Mg is bonded in a 12-coordinate geometry to four Mg, one Fe, and one Co atom. The Mg–Fe bond length is 2.78 Å. The Mg–Co bond length is 2.79 Å. In the sixth Mg site, Mg is bonded in a distorted single-bond geometry to five Mg and one Fe atom. The Mg–Fe bond length is 2.85 Å. In the seventh Mg site, Mg is bonded in a distorted single-bond geometry to five Mg and one Co atom. The Mg–Co bond length is 2.86 Å. Fe is bonded to ten Mg and two equivalent Co atoms to form distorted FeMg10Co2 cuboctahedra that share corners with six equivalent FeMg10Co2 cuboctahedra, corners with twelve MgMg12 cuboctahedra, edges with two equivalent CoMg10Fe2 cuboctahedra, edges with four equivalent MgMg8Fe2Co2 cuboctahedra, faces with two equivalent CoMg10Fe2 cuboctahedra, and faces with six MgMg12 cuboctahedra. Both Fe–Co bond lengths are 3.12 Å. Co is bonded to ten Mg and two equivalent Fe atoms to form distorted CoMg10Fe2 cuboctahedra that share corners with six equivalent CoMg10Fe2 cuboctahedra, corners with twelve MgMg12 cuboctahedra, edges with two equivalent FeMg10Co2 cuboctahedra, edges with four equivalent MgMg8Fe2Co2 cuboctahedra, faces with two equivalent FeMg10Co2 cuboctahedra, and faces with six MgMg12 cuboctahedra.

36 MATERIALS SCIENCE↗

Materials Data on FeBP2O11 by Materials Project

(FeB(PO5)2)2O2 crystallizes in the hexagonal P6_122 space group. The structure is three-dimensional and consists of six water molecules and one FeB(PO5)2 framework. In the FeB(PO5)2 framework, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with four equivalent PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.72–1.99 Å. B is bonded to four O atoms to form BO4 tetrahedra that share corners with four equivalent PO4 tetrahedra. There is two shorter (1.47 Å) and two longer (1.48 Å) B–O bond length. P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with two equivalent BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–50°. There are a spread of P–O bond distances ranging from 1.52–1.57 Å. There are five inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one B and one P atom. In the second O site, O is bonded in a single-bond geometry to one Fe atom. In the third O site, O is bonded in a bent 120 degrees geometry to one B and one P atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to one Fe and one P atom. In the fifth O site, O is bonded in a bent 120 degrees geometry to one Fe and one P atom.

36 MATERIALS SCIENCE↗

Materials Data on Sm2Fe17CN by Materials Project

Sm2Fe17CN crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Sm is bonded in a distorted bent 120 degrees geometry to nine Fe, one C, and one N atom. There are a spread of Sm–Fe bond distances ranging from 3.08–3.36 Å. The Sm–C bond length is 2.56 Å. The Sm–N bond length is 2.48 Å. There are ten inequivalent Fe sites. In the first Fe site, Fe is bonded in a 2-coordinate geometry to one Sm and thirteen Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.37–2.75 Å. In the second Fe site, Fe is bonded in a single-bond geometry to five Fe and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.47–2.57 Å. The Fe–C bond length is 1.91 Å. In the third Fe site, Fe is bonded in a single-bond geometry to five Fe and one N atom. There are a spread of Fe–Fe bond distances ranging from 2.48–2.57 Å. The Fe–N bond length is 1.93 Å. In the fourth Fe site, Fe is bonded to three equivalent Sm and nine Fe atoms to form FeSm3Fe9 cuboctahedra that share corners with eleven FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, corners with two equivalent NSm2Fe4 octahedra, edges with four FeSm3Fe9 cuboctahedra, faces with eight FeSm3Fe9 cuboctahedra, a faceface with one CSm2Fe4 octahedra, and a faceface with one NSm2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 63–70°. There are a spread of Fe–Fe bond distances ranging from 2.48–2.66 Å. In the fifth Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. There are two shorter (2.44 Å) and one longer (2.47 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.86 Å. In the sixth Fe site, Fe is bonded in a single-bond geometry to six Fe and one N atom. There are two shorter (2.44 Å) and one longer (2.48 Å) Fe–Fe bond lengths. The Fe–N bond length is 1.89 Å. In the seventh Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with eight FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, corners with two equivalent NSm2Fe4 octahedra, edges with three FeSm2Fe10 cuboctahedra, an edgeedge with one CSm2Fe4 octahedra, an edgeedge with one NSm2Fe4 octahedra, and faces with nine FeSm3Fe9 cuboctahedra. The corner-sharing octahedra tilt angles range from 22–29°. There are one shorter (2.44 Å) and one longer (2.45 Å) Fe–Fe bond lengths. In the eighth Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form FeSm2Fe10 cuboctahedra that share corners with eight FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with four FeSm2Fe10 cuboctahedra, faces with eight FeSm3Fe9 cuboctahedra, and faces with two equivalent NSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. In the ninth Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with eight FeSm3Fe9 cuboctahedra, corners with two equivalent NSm2Fe4 octahedra, edges with four FeSm2Fe10 cuboctahedra, faces with eight FeSm3Fe9 cuboctahedra, and faces with two equivalent CSm2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. In the tenth Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form distorted FeSm2Fe10 cuboctahedra that share corners with fourteen FeSm3Fe9 cuboctahedra, edges with two equivalent FeSm3Fe9 cuboctahedra, faces with ten FeSm3Fe9 cuboctahedra, faces with two equivalent CSm2Fe4 octahedra, and faces with two equivalent NSm2Fe4 octahedra. C is bonded to two equivalent Sm and four Fe atoms to form CSm2Fe4 octahedra that share corners with ten FeSm3Fe9 cuboctahedra, corners with two equivalent NSm2Fe4 octahedra, edges with two equivalent FeSm2Fe10 cuboctahedra, and faces with six FeSm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 62°. N is bonded to two equivalent Sm and four Fe atoms to form NSm2Fe4 octahedra that share corners with ten FeSm3Fe9 cuboctahedra, corners with two equivalent CSm2Fe4 octahedra, edges with two equivalent FeSm2Fe10 cuboctahedra, and faces with six FeSm2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 62°.

36 MATERIALS SCIENCE↗