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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ca3(AlGe)2 by Materials Project

Ca3(AlGe)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to eight equivalent Al and four equivalent Ge atoms to form a mixture of edge and face-sharing CaAl8Ge4 cuboctahedra. All Ca–Al bond lengths are 3.33 Å. All Ca–Ge bond lengths are 3.56 Å. In the second Ca site, Ca is bonded in a 7-coordinate geometry to two equivalent Al and five equivalent Ge atoms. Both Ca–Al bond lengths are 3.17 Å. There are one shorter (3.14 Å) and four longer (3.16 Å) Ca–Ge bond lengths. Al is bonded in a 2-coordinate geometry to six Ca, one Al, and two equivalent Ge atoms. The Al–Al bond length is 2.54 Å. Both Al–Ge bond lengths are 2.53 Å. Ge is bonded in a 7-coordinate geometry to seven Ca and two equivalent Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca3Al2Ge3 by Materials Project

Ca3Al2Ge3 is Magnesium tetraboride-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Ca sites. In the first Ca site, Ca is bonded in a 11-coordinate geometry to five Al and six Ge atoms. There are a spread of Ca–Al bond distances ranging from 3.07–3.32 Å. There are a spread of Ca–Ge bond distances ranging from 3.07–3.49 Å. In the second Ca site, Ca is bonded in a 4-coordinate geometry to three Al and five Ge atoms. There are two shorter (3.28 Å) and one longer (3.42 Å) Ca–Al bond lengths. There are a spread of Ca–Ge bond distances ranging from 3.02–3.48 Å. In the third Ca site, Ca is bonded in a 6-coordinate geometry to three Al and six Ge atoms. There are one shorter (3.18 Å) and two longer (3.46 Å) Ca–Al bond lengths. There are a spread of Ca–Ge bond distances ranging from 3.01–3.26 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 4-coordinate geometry to five Ca and four Ge atoms. There are a spread of Al–Ge bond distances ranging from 2.57–2.79 Å. In the second Al site, Al is bonded in a 4-coordinate geometry to six Ca and four Ge atoms. There are a spread of Al–Ge bond distances ranging from 2.61–2.65 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 8-coordinate geometry to five Ca and three Al atoms. In the second Ge site, Ge is bonded in a 7-coordinate geometry to five Ca and three Al atoms. In the third Ge site, Ge is bonded in a 9-coordinate geometry to seven Ca and two Al atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca(AlGe)2 by Materials Project

CaAl2Ge2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Ca is bonded to six equivalent Ge atoms to form CaGe6 octahedra that share corners with twelve equivalent AlGe4 tetrahedra, edges with six equivalent CaGe6 octahedra, and edges with six equivalent AlGe4 tetrahedra. All Ca–Ge bond lengths are 3.06 Å. Al is bonded to four equivalent Ge atoms to form AlGe4 tetrahedra that share corners with six equivalent CaGe6 octahedra, corners with six equivalent AlGe4 tetrahedra, edges with three equivalent CaGe6 octahedra, and edges with three equivalent AlGe4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–53°. There are three shorter (2.56 Å) and one longer (2.65 Å) Al–Ge bond lengths. Ge is bonded to three equivalent Ca and four equivalent Al atoms to form a mixture of distorted edge and corner-sharing GeCa3Al4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗