Materials Data on ErAlCu4 by Materials Project

Abstract

ErCu4Al crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Er is bonded in a 6-coordinate geometry to fifteen Cu and three equivalent Al atoms. There are three shorter (2.98 Å) and twelve longer (3.27 Å) Er–Cu bond lengths. All Er–Al bond lengths are 2.98 Å. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to three equivalent Er, six equivalent Cu, and three equivalent Al atoms to form CuEr3Al3Cu6 cuboctahedra that share corners with nine equivalent AlEr3Cu9 cuboctahedra, corners with twelve equivalent CuEr4Al2Cu6 cuboctahedra, edges with six equivalent CuEr3Al3Cu6 cuboctahedra, faces with three equivalent AlEr3Cu9 cuboctahedra, and faces with twenty CuEr3Al3Cu6 cuboctahedra. All Cu–Cu bond lengths are 2.49 Å. All Cu–Al bond lengths are 2.98 Å. In the second Cu site, Cu is bonded to four equivalent Er, six Cu, and two equivalent Al atoms to form distorted CuEr4Al2Cu6 cuboctahedra that share corners with four equivalent AlEr3Cu9 cuboctahedra, corners with twenty CuEr3Al3Cu6 cuboctahedra, edges with ten equivalent CuEr4Al2Cu6 cuboctahedra, faces with six equivalent AlEr3Cu9 cuboctahedra, and faces with sixteen CuEr3Al3Cu6 cuboctahedra. There are two shorter (2.57 Å) and two longer (2.59 Å) Cu–Cu bond lengths. Both Cu–Al bond lengths are 2.50 Å. Al is bonded to three equivalent Er and nine Cu atoms to form distorted AlEr3Cu9 cuboctahedra that share corners with twenty-one CuEr3Al3Cu6 cuboctahedra, edges with six equivalent AlEr3Cu9 cuboctahedra, faces with two equivalent AlEr3Cu9 cuboctahedra, and faces with twenty-one CuEr3Al3Cu6 cuboctahedra.