Materials Data on UCu2(SiNi4)2 by Materials Project

Abstract

UCu2(Ni4Si)2 crystallizes in the orthorhombic Fmmm space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to twelve Ni, four equivalent Cu, and four equivalent Si atoms. There are four shorter (2.82 Å) and eight longer (3.03 Å) U–Ni bond lengths. All U–Cu bond lengths are 3.10 Å. All U–Si bond lengths are 3.15 Å. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded in a 12-coordinate geometry to two equivalent U, six Ni, two equivalent Cu, and two equivalent Si atoms. There are a spread of Ni–Ni bond distances ranging from 2.47–2.65 Å. Both Ni–Cu bond lengths are 2.42 Å. Both Ni–Si bond lengths are 2.35 Å. In the second Ni site, Ni is bonded in a 10-coordinate geometry to one U, five Ni, two equivalent Cu, and two equivalent Si atoms. The Ni–Ni bond length is 2.51 Å. Both Ni–Cu bond lengths are 2.55 Å. Both Ni–Si bond lengths are 2.44 Å. Cu is bonded to two equivalent U, eight Ni, and two equivalent Cu atoms to form CuU2Cu2Ni8 cuboctahedra that share corners with four equivalent SiU2Si2Ni8 cuboctahedra, corners with six equivalent CuU2Cu2Ni8 cuboctahedra, edges with four equivalent SiU2Si2Ni8 cuboctahedra, faces with two equivalent CuU2Cu2Ni8 cuboctahedra, and faces with four equivalent SiU2Si2Ni8 cuboctahedra. Both Cu–Cu bond lengths are 2.43 Å. Si is bonded to two equivalent U, eight Ni, and two equivalent Si atoms to form distorted SiU2Si2Ni8 cuboctahedra that share corners with four equivalent CuU2Cu2Ni8 cuboctahedra, corners with six equivalent SiU2Si2Ni8 cuboctahedra, edges with four equivalent CuU2Cu2Ni8 cuboctahedra, faces with two equivalent SiU2Si2Ni8 cuboctahedra, and faces with four equivalent CuU2Cu2Ni8 cuboctahedra. Both Si–Si bond lengths are 2.43 Å.