Materials Data on U2CuSi3 by Materials Project
U2CuSi3 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. there are two inequivalent U5+ sites. In the first U5+ site, U5+ is bonded in a distorted q4 geometry to ten Si4- atoms. There are a spread of U–Si bond distances ranging from 2.99–3.06 Å. In the second U5+ site, U5+ is bonded to eight Si4- atoms to form a mixture of distorted face, edge, and corner-sharing USi8 hexagonal bipyramids. There are a spread of U–Si bond distances ranging from 2.98–3.07 Å. Cu2+ is bonded in a trigonal planar geometry to three Si4- atoms. There are two shorter (2.30 Å) and one longer (2.31 Å) Cu–Si bond lengths. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to six U5+ and three Si4- atoms. There are one shorter (2.31 Å) and two longer (2.34 Å) Si–Si bond lengths. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to six U5+, two equivalent Cu2+, and one Si4- atom. In the third Si4- site, Si4- is bonded in a 9-coordinate geometry to six U5+, one Cu2+, and two equivalent Si4- atoms.