DOE OSTI2020
U4RhGa12 crystallizes in the cubic Im-3m space group. The structure is three-dimensional. U is bonded to twelve Ga atoms to form UGa12 cuboctahedra that share corners with twelve equivalent UGa12 cuboctahedra, edges with twelve equivalent GaU4Ga8 cuboctahedra, faces with six equivalent UGa12 cuboctahedra, faces with six equivalent GaU4Ga8 cuboctahedra, and faces with two equivalent RhGa6 octahedra. There are six shorter (3.05 Å) and six longer (3.07 Å) U–Ga bond lengths. Rh is bonded to six equivalent Ga atoms to form RhGa6 octahedra that share corners with twenty-four equivalent GaU4Ga8 cuboctahedra and faces with eight equivalent UGa12 cuboctahedra. All Rh–Ga bond lengths are 2.51 Å. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded to four equivalent U and eight Ga atoms to form distorted GaU4Ga8 cuboctahedra that share corners with four equivalent GaU4Ga8 cuboctahedra, corners with four equivalent RhGa6 octahedra, edges with eight equivalent UGa12 cuboctahedra, edges with eight equivalent GaU4Ga8 cuboctahedra, faces with four equivalent UGa12 cuboctahedra, and faces with six equivalent GaU4Ga8 cuboctahedra. The corner-sharing octahedral tilt angles are 50°. There are four shorter (2.81 Å) and four longer (3.05 Å) Ga–Ga bond lengths. In the second Ga site, Ga is bonded in a distorted single-bond geometry to four equivalent U, one Rh, and four equivalent Ga atoms.