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DOE OSTI2020

Materials Data on Mn4Nb2Si5 by Materials Project

Nb2Mn4Si5 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. Nb2+ is bonded to six Si+2.40- atoms to form distorted NbSi6 octahedra that share corners with four equivalent NbSi6 octahedra, corners with six equivalent MnSi7 pentagonal bipyramids, edges with two equivalent NbSi6 octahedra, faces with two equivalent NbSi6 octahedra, and faces with four equivalent MnSi7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are a spread of Nb–Si bond distances ranging from 2.60–2.62 Å. There are two inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to seven Si+2.40- atoms to form distorted MnSi7 pentagonal bipyramids that share corners with six equivalent NbSi6 octahedra, corners with six equivalent MnSi7 pentagonal bipyramids, edges with three equivalent MnSi7 pentagonal bipyramids, faces with four equivalent NbSi6 octahedra, and faces with two equivalent MnSi7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 41–55°. There are a spread of Mn–Si bond distances ranging from 2.46–2.90 Å. In the second Mn2+ site, Mn2+ is bonded in a 7-coordinate geometry to seven Si+2.40- atoms. There are a spread of Mn–Si bond distances ranging from 2.31–2.81 Å. There are three inequivalent Si+2.40- sites. In the first Si+2.40- site, Si+2.40- is bonded in a 8-coordinate geometry to two equivalent Nb2+, five Mn2+, and one Si+2.40- atom. The Si–Si bond length is 2.42 Å. In the second Si+2.40- site, Si+2.40- is bonded in a 9-coordinate geometry to four equivalent Nb2+ and five Mn2+ atoms. In the third Si+2.40- site, Si+2.40- is bonded in a 10-coordinate geometry to eight Mn2+ and two equivalent Si+2.40- atoms. Both Si–Si bond lengths are 2.58 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MnNbSi by Materials Project

NbMnSi crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Nb2+ is bonded to five Si4- atoms to form distorted NbSi5 square pyramids that share corners with ten equivalent NbSi5 square pyramids, corners with six equivalent MnSi4 tetrahedra, edges with six equivalent NbSi5 square pyramids, and edges with six equivalent MnSi4 tetrahedra. There are four shorter (2.61 Å) and one longer (2.64 Å) Nb–Si bond lengths. Mn2+ is bonded to four Si4- atoms to form distorted MnSi4 tetrahedra that share corners with six equivalent NbSi5 square pyramids, corners with ten equivalent MnSi4 tetrahedra, edges with six equivalent NbSi5 square pyramids, and edges with two equivalent MnSi4 tetrahedra. There are two shorter (2.35 Å) and two longer (2.48 Å) Mn–Si bond lengths. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to three equivalent Nb2+ and six equivalent Mn2+ atoms. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to six equivalent Nb2+ and three equivalent Mn2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn8Nb3Si by Materials Project

Nb3Mn8Si crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are three inequivalent Nb sites. In the first Nb site, Nb is bonded in a 3-coordinate geometry to one Nb, twelve Mn, and three equivalent Si atoms. The Nb–Nb bond length is 2.95 Å. There are a spread of Nb–Mn bond distances ranging from 2.72–2.81 Å. All Nb–Si bond lengths are 2.90 Å. In the second Nb site, Nb is bonded in a 12-coordinate geometry to four Nb and twelve Mn atoms. All Nb–Nb bond lengths are 2.98 Å. There are nine shorter (2.79 Å) and three longer (2.83 Å) Nb–Mn bond lengths. In the third Nb site, Nb is bonded in a 1-coordinate geometry to three equivalent Nb, twelve Mn, and one Si atom. There are a spread of Nb–Mn bond distances ranging from 2.74–2.92 Å. The Nb–Si bond length is 2.79 Å. There are four inequivalent Mn sites. In the first Mn site, Mn is bonded to three equivalent Nb, six Mn, and three equivalent Si atoms to form MnMn6Nb3Si3 cuboctahedra that share corners with twelve MnMn6Nb4Si2 cuboctahedra, edges with six equivalent MnMn6Nb3Si3 cuboctahedra, and faces with twenty MnMn6Nb6 cuboctahedra. There are three shorter (2.37 Å) and three longer (2.42 Å) Mn–Mn bond lengths. All Mn–Si bond lengths are 2.79 Å. In the second Mn site, Mn is bonded to six Nb and six Mn atoms to form MnMn6Nb6 cuboctahedra that share corners with twelve MnMn6Nb4Si2 cuboctahedra, edges with six equivalent MnMn6Nb6 cuboctahedra, and faces with twenty MnMn6Nb3Si3 cuboctahedra. There are three shorter (2.38 Å) and three longer (2.49 Å) Mn–Mn bond lengths. In the third Mn site, Mn is bonded to four Nb, six Mn, and two equivalent Si atoms to form MnMn6Nb4Si2 cuboctahedra that share corners with eighteen MnMn6Nb3Si3 cuboctahedra, edges with six MnMn6Nb4Si2 cuboctahedra, and faces with eighteen MnMn6Nb3Si3 cuboctahedra. There are two shorter (2.32 Å) and two longer (2.44 Å) Mn–Mn bond lengths. Both Mn–Si bond lengths are 2.79 Å. In the fourth Mn site, Mn is bonded to five Nb, six Mn, and one Si atom to form distorted MnMn6Nb5Si cuboctahedra that share corners with eighteen MnMn6Nb3Si3 cuboctahedra, edges with six MnMn6Nb4Si2 cuboctahedra, and faces with eighteen MnMn6Nb3Si3 cuboctahedra. There are two shorter (2.28 Å) and two longer (2.48 Å) Mn–Mn bond lengths. The Mn–Si bond length is 2.75 Å. Si is bonded in a 4-coordinate geometry to four Nb and twelve Mn atoms.

36 MATERIALS SCIENCE↗