Materials Data on U2Si4Mo3 by Materials Project

Abstract

U2Mo3Si4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. U3+ is bonded to seven Si4- atoms to form distorted USi7 pentagonal bipyramids that share corners with four equivalent MoSi6 octahedra, corners with six equivalent USi7 pentagonal bipyramids, corners with five equivalent MoSi6 pentagonal pyramids, edges with three equivalent USi7 pentagonal bipyramids, edges with two equivalent MoSi6 pentagonal pyramids, faces with two equivalent MoSi6 octahedra, faces with two equivalent USi7 pentagonal bipyramids, and faces with four equivalent MoSi6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 46–53°. There are a spread of U–Si bond distances ranging from 2.81–2.96 Å. There are two inequivalent Mo+3.33+ sites. In the first Mo+3.33+ site, Mo+3.33+ is bonded to six Si4- atoms to form distorted MoSi6 pentagonal pyramids that share corners with three equivalent MoSi6 octahedra, corners with five equivalent USi7 pentagonal bipyramids, corners with four equivalent MoSi6 pentagonal pyramids, edges with two equivalent USi7 pentagonal bipyramids, edges with four equivalent MoSi6 pentagonal pyramids, faces with two equivalent MoSi6 octahedra, and faces with four equivalent USi7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 40–42°. There are a spread of Mo–Si bond distances ranging from 2.51–2.63 Å. In the second Mo+3.33+ site, Mo+3.33+ is bonded to six Si4- atoms to form MoSi6 octahedra that share corners with four equivalent MoSi6 octahedra, corners with eight equivalent USi7 pentagonal bipyramids, corners with six equivalent MoSi6 pentagonal pyramids, faces with four equivalent USi7 pentagonal bipyramids, and faces with four equivalent MoSi6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 50°. There are a spread of Mo–Si bond distances ranging from 2.63–2.68 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to three equivalent U3+, five Mo+3.33+, and one Si4- atom. The Si–Si bond length is 2.58 Å. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to four equivalent U3+, four Mo+3.33+, and one Si4- atom. The Si–Si bond length is 2.52 Å.