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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on CaLa3Si8 by Materials Project

CaLa3Si8 is hexagonal omega structure-derived structured and crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. Ca2+ is bonded to twelve Si1- atoms to form CaSi12 cuboctahedra that share edges with four equivalent CaSi12 cuboctahedra, edges with eight LaSi12 cuboctahedra, faces with four equivalent CaSi12 cuboctahedra, and faces with four LaSi12 cuboctahedra. There are four shorter (3.16 Å) and eight longer (3.24 Å) Ca–Si bond lengths. There are three inequivalent La2+ sites. In the first La2+ site, La2+ is bonded to twelve Si1- atoms to form a mixture of edge and face-sharing LaSi12 cuboctahedra. There are four shorter (3.18 Å) and eight longer (3.24 Å) La–Si bond lengths. In the second La2+ site, La2+ is bonded to twelve Si1- atoms to form LaSi12 cuboctahedra that share edges with four equivalent CaSi12 cuboctahedra, edges with eight LaSi12 cuboctahedra, faces with two equivalent CaSi12 cuboctahedra, and faces with six LaSi12 cuboctahedra. There are a spread of La–Si bond distances ranging from 3.17–3.24 Å. In the third La2+ site, La2+ is bonded to twelve Si1- atoms to form LaSi12 cuboctahedra that share edges with four equivalent CaSi12 cuboctahedra, edges with eight LaSi12 cuboctahedra, faces with two equivalent CaSi12 cuboctahedra, and faces with six LaSi12 cuboctahedra. There are a spread of La–Si bond distances ranging from 3.17–3.24 Å. There are six inequivalent Si1- sites. In the first Si1- site, Si1- is bonded in a 9-coordinate geometry to four equivalent Ca2+, two equivalent La2+, and three Si1- atoms. There are one shorter (2.36 Å) and two longer (2.42 Å) Si–Si bond lengths. In the second Si1- site, Si1- is bonded in a 9-coordinate geometry to six La2+ and three Si1- atoms. There are one shorter (2.39 Å) and two longer (2.43 Å) Si–Si bond lengths. In the third Si1- site, Si1- is bonded in a 9-coordinate geometry to two equivalent Ca2+, four equivalent La2+, and three Si1- atoms. The Si–Si bond length is 2.39 Å. In the fourth Si1- site, Si1- is bonded in a 9-coordinate geometry to six La2+ and three Si1- atoms. The Si–Si bond length is 2.39 Å. In the fifth Si1- site, Si1- is bonded in a 9-coordinate geometry to four equivalent Ca2+, two equivalent La2+, and three Si1- atoms. Both Si–Si bond lengths are 2.42 Å. In the sixth Si1- site, Si1- is bonded in a 9-coordinate geometry to six La2+ and three Si1- atoms. Both Si–Si bond lengths are 2.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaLaSi4 by Materials Project

CaLaSi4 is hexagonal omega structure-derived structured and crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Ca is bonded to twelve Si atoms to form CaSi12 cuboctahedra that share edges with four equivalent CaSi12 cuboctahedra, edges with eight equivalent LaSi12 cuboctahedra, faces with four equivalent CaSi12 cuboctahedra, and faces with four equivalent LaSi12 cuboctahedra. There are four shorter (3.11 Å) and eight longer (3.30 Å) Ca–Si bond lengths. La is bonded to twelve Si atoms to form LaSi12 cuboctahedra that share edges with four equivalent LaSi12 cuboctahedra, edges with eight equivalent CaSi12 cuboctahedra, faces with four equivalent CaSi12 cuboctahedra, and faces with four equivalent LaSi12 cuboctahedra. There are four shorter (3.11 Å) and eight longer (3.30 Å) La–Si bond lengths. There are four inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to four equivalent Ca, two equivalent La, and three Si atoms. There are one shorter (2.32 Å) and two longer (2.43 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 9-coordinate geometry to two equivalent Ca, four equivalent La, and three Si atoms. The Si–Si bond length is 2.31 Å. In the third Si site, Si is bonded in a 9-coordinate geometry to four equivalent Ca, two equivalent La, and three Si atoms. Both Si–Si bond lengths are 2.43 Å. In the fourth Si site, Si is bonded in a 9-coordinate geometry to four equivalent Ca, two equivalent La, and three Si atoms. All Si–Ca bond lengths are 3.30 Å. Both Si–La bond lengths are 3.11 Å. There are one shorter (2.32 Å) and two longer (2.43 Å) Si–Si bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca3LaSi8 by Materials Project

Ca3LaSi8 is hexagonal omega structure-derived structured and crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to twelve Si1- atoms to form a mixture of face and edge-sharing CaSi12 cuboctahedra. There are four shorter (3.10 Å) and eight longer (3.26 Å) Ca–Si bond lengths. In the second Ca2+ site, Ca2+ is bonded to twelve Si1- atoms to form CaSi12 cuboctahedra that share edges with four equivalent LaSi12 cuboctahedra, edges with eight CaSi12 cuboctahedra, faces with two equivalent LaSi12 cuboctahedra, and faces with six CaSi12 cuboctahedra. There are a spread of Ca–Si bond distances ranging from 3.09–3.27 Å. In the third Ca2+ site, Ca2+ is bonded to twelve Si1- atoms to form CaSi12 cuboctahedra that share edges with four equivalent LaSi12 cuboctahedra, edges with eight CaSi12 cuboctahedra, faces with two equivalent LaSi12 cuboctahedra, and faces with six CaSi12 cuboctahedra. There are a spread of Ca–Si bond distances ranging from 3.09–3.27 Å. La2+ is bonded to twelve Si1- atoms to form LaSi12 cuboctahedra that share edges with four equivalent LaSi12 cuboctahedra, edges with eight CaSi12 cuboctahedra, faces with four CaSi12 cuboctahedra, and faces with four equivalent LaSi12 cuboctahedra. There are four shorter (3.10 Å) and eight longer (3.26 Å) La–Si bond lengths. There are six inequivalent Si1- sites. In the first Si1- site, Si1- is bonded in a 9-coordinate geometry to two equivalent Ca2+, four equivalent La2+, and three Si1- atoms. There are one shorter (2.30 Å) and two longer (2.41 Å) Si–Si bond lengths. In the second Si1- site, Si1- is bonded in a 9-coordinate geometry to six Ca2+ and three Si1- atoms. There are one shorter (2.29 Å) and two longer (2.41 Å) Si–Si bond lengths. In the third Si1- site, Si1- is bonded in a 9-coordinate geometry to four equivalent Ca2+, two equivalent La2+, and three Si1- atoms. The Si–Si bond length is 2.30 Å. In the fourth Si1- site, Si1- is bonded in a 9-coordinate geometry to six Ca2+ and three Si1- atoms. The Si–Si bond length is 2.30 Å. In the fifth Si1- site, Si1- is bonded in a 9-coordinate geometry to two equivalent Ca2+, four equivalent La2+, and three Si1- atoms. Both Si–Si bond lengths are 2.41 Å. In the sixth Si1- site, Si1- is bonded in a 9-coordinate geometry to four equivalent Ca2+, two equivalent La2+, and three Si1- atoms.

36 MATERIALS SCIENCE↗