Materials Data on Sc3(CuSi)4 by Materials Project

Abstract

Sc3(CuSi)4 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded to six Si4- atoms to form ScSi6 octahedra that share corners with four equivalent CuCuSi4 tetrahedra, edges with two equivalent ScSi6 octahedra, and edges with eight equivalent CuCuSi4 tetrahedra. There are four shorter (2.82 Å) and two longer (2.84 Å) Sc–Si bond lengths. In the second Sc3+ site, Sc3+ is bonded in a distorted hexagonal planar geometry to six Si4- atoms. There are four shorter (2.84 Å) and two longer (2.86 Å) Sc–Si bond lengths. Cu+1.75+ is bonded to one Cu+1.75+ and four Si4- atoms to form distorted CuCuSi4 tetrahedra that share a cornercorner with one ScSi6 octahedra, corners with ten equivalent CuCuSi4 tetrahedra, edges with two equivalent ScSi6 octahedra, and edges with three equivalent CuCuSi4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. The Cu–Cu bond length is 2.49 Å. There are a spread of Cu–Si bond distances ranging from 2.36–2.45 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to three Sc3+ and six equivalent Cu+1.75+ atoms. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to six Sc3+, two equivalent Cu+1.75+, and one Si4- atom. The Si–Si bond length is 2.41 Å.