Materials Data on Sc2Si4W3 by Materials Project

Abstract

Sc2W3Si4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sc3+ is bonded to seven Si4- atoms to form distorted ScSi7 pentagonal bipyramids that share corners with four equivalent WSi6 octahedra, corners with six equivalent ScSi7 pentagonal bipyramids, corners with five equivalent WSi6 pentagonal pyramids, edges with two equivalent ScSi7 pentagonal bipyramids, edges with three equivalent WSi6 pentagonal pyramids, faces with two equivalent WSi6 octahedra, faces with three equivalent ScSi7 pentagonal bipyramids, and faces with three equivalent WSi6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 47–51°. There are a spread of Sc–Si bond distances ranging from 2.70–2.89 Å. There are two inequivalent W+3.33+ sites. In the first W+3.33+ site, W+3.33+ is bonded to six Si4- atoms to form WSi6 octahedra that share corners with four equivalent WSi6 octahedra, corners with eight equivalent ScSi7 pentagonal bipyramids, corners with six equivalent WSi6 pentagonal pyramids, faces with four equivalent ScSi7 pentagonal bipyramids, and faces with four equivalent WSi6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of W–Si bond distances ranging from 2.56–2.75 Å. In the second W+3.33+ site, W+3.33+ is bonded to six Si4- atoms to form distorted WSi6 pentagonal pyramids that share corners with three equivalent WSi6 octahedra, corners with five equivalent ScSi7 pentagonal bipyramids, corners with four equivalent WSi6 pentagonal pyramids, edges with three equivalent ScSi7 pentagonal bipyramids, edges with three equivalent WSi6 pentagonal pyramids, faces with two equivalent WSi6 octahedra, faces with three equivalent ScSi7 pentagonal bipyramids, and a faceface with one WSi6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 39–40°. There are a spread of W–Si bond distances ranging from 2.51–2.63 Å. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to four equivalent Sc3+, four W+3.33+, and one Si4- atom. The Si–Si bond length is 2.53 Å. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to two equivalent Sc3+, six W+3.33+, and one Si4- atom. The Si–Si bond length is 2.49 Å. In the third Si4- site, Si4- is bonded in a 9-coordinate geometry to four equivalent Sc3+, four W+3.33+, and one Si4- atom.