DOE OSTI2020
Y4ScSi10 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. there are two inequivalent Y sites. In the first Y site, Y is bonded to twelve Si atoms to form YSi12 cuboctahedra that share edges with six equivalent YSi12 cuboctahedra, edges with six equivalent ScSi12 cuboctahedra, a faceface with one ScSi12 cuboctahedra, and faces with seven YSi12 cuboctahedra. All Y–Si bond lengths are 3.10 Å. In the second Y site, Y is bonded to twelve Si atoms to form a mixture of edge and face-sharing YSi12 cuboctahedra. There are six shorter (3.09 Å) and six longer (3.10 Å) Y–Si bond lengths. Sc is bonded to twelve equivalent Si atoms to form ScSi12 cuboctahedra that share edges with twelve equivalent YSi12 cuboctahedra, faces with two equivalent YSi12 cuboctahedra, and faces with six equivalent ScSi12 cuboctahedra. All Sc–Si bond lengths are 2.97 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to three equivalent Y, three equivalent Sc, and three equivalent Si atoms. All Si–Si bond lengths are 2.34 Å. In the second Si site, Si is bonded in a 9-coordinate geometry to six Y and three equivalent Si atoms. All Si–Si bond lengths are 2.34 Å. In the third Si site, Si is bonded in a 9-coordinate geometry to six equivalent Y and three equivalent Si atoms. All Si–Si bond lengths are 2.34 Å.