Materials Data on U2Cr3Si by Materials Project
U2Cr3Si crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. U is bonded in a 10-coordinate geometry to one U, nine Cr, and three equivalent Si atoms. The U–U bond length is 2.63 Å. There are a spread of U–Cr bond distances ranging from 2.87–3.07 Å. There are one shorter (3.02 Å) and two longer (3.03 Å) U–Si bond lengths. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded to six equivalent U, four Cr, and two equivalent Si atoms to form distorted CrU6Cr4Si2 cuboctahedra that share corners with four equivalent SiU6Cr6 cuboctahedra, corners with fourteen CrU6Cr4Si2 cuboctahedra, edges with six equivalent CrU6Cr4Si2 cuboctahedra, faces with six equivalent SiU6Cr6 cuboctahedra, and faces with twelve CrU6Cr4Si2 cuboctahedra. There are a spread of Cr–Cr bond distances ranging from 2.46–2.64 Å. Both Cr–Si bond lengths are 2.53 Å. In the second Cr site, Cr is bonded to six equivalent U, four Cr, and two equivalent Si atoms to form distorted CrU6Cr4Si2 cuboctahedra that share corners with four equivalent SiU6Cr6 cuboctahedra, corners with fourteen CrU6Cr4Si2 cuboctahedra, edges with six equivalent CrU6Cr4Si2 cuboctahedra, faces with six equivalent SiU6Cr6 cuboctahedra, and faces with twelve CrU6Cr4Si2 cuboctahedra. There are one shorter (2.47 Å) and one longer (2.63 Å) Cr–Cr bond lengths. Both Cr–Si bond lengths are 2.53 Å. In the third Cr site, Cr is bonded to six equivalent U, four Cr, and two equivalent Si atoms to form distorted CrU6Cr4Si2 cuboctahedra that share corners with four equivalent SiU6Cr6 cuboctahedra, corners with fourteen CrU6Cr4Si2 cuboctahedra, edges with six equivalent CrU6Cr4Si2 cuboctahedra, faces with six equivalent SiU6Cr6 cuboctahedra, and faces with twelve CrU6Cr4Si2 cuboctahedra. Both Cr–Si bond lengths are 2.53 Å. Si is bonded to six equivalent U and six Cr atoms to form SiU6Cr6 cuboctahedra that share corners with twelve CrU6Cr4Si2 cuboctahedra, edges with six equivalent SiU6Cr6 cuboctahedra, faces with two equivalent SiU6Cr6 cuboctahedra, and faces with eighteen CrU6Cr4Si2 cuboctahedra.