Materials Data on SmAlCu4 by Materials Project

Abstract

SmCu4Al crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Sm is bonded in a 6-coordinate geometry to fifteen Cu and three equivalent Al atoms. There are three shorter (3.04 Å) and twelve longer (3.31 Å) Sm–Cu bond lengths. All Sm–Al bond lengths are 3.04 Å. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to three equivalent Sm, six equivalent Cu, and three equivalent Al atoms to form CuSm3Al3Cu6 cuboctahedra that share corners with nine equivalent AlSm3Cu9 cuboctahedra, corners with twelve equivalent CuSm4Al2Cu6 cuboctahedra, edges with six equivalent CuSm3Al3Cu6 cuboctahedra, faces with three equivalent AlSm3Cu9 cuboctahedra, and faces with twenty CuSm3Al3Cu6 cuboctahedra. All Cu–Cu bond lengths are 2.50 Å. All Cu–Al bond lengths are 3.04 Å. In the second Cu site, Cu is bonded to four equivalent Sm, six Cu, and two equivalent Al atoms to form distorted CuSm4Al2Cu6 cuboctahedra that share corners with four equivalent AlSm3Cu9 cuboctahedra, corners with twenty CuSm3Al3Cu6 cuboctahedra, edges with ten equivalent CuSm4Al2Cu6 cuboctahedra, faces with six equivalent AlSm3Cu9 cuboctahedra, and faces with sixteen CuSm3Al3Cu6 cuboctahedra. There are two shorter (2.62 Å) and two longer (2.66 Å) Cu–Cu bond lengths. Both Cu–Al bond lengths are 2.52 Å. Al is bonded to three equivalent Sm and nine Cu atoms to form distorted AlSm3Cu9 cuboctahedra that share corners with twenty-one CuSm3Al3Cu6 cuboctahedra, edges with six equivalent AlSm3Cu9 cuboctahedra, faces with two equivalent AlSm3Cu9 cuboctahedra, and faces with twenty-one CuSm3Al3Cu6 cuboctahedra.