U3Yb crystallizes in the hexagonal P6_3/mmc space group. U(1) is bonded to eight equivalent U(1) and four equivalent Yb(1) atoms to form distorted UYb4U8 cuboctahedra that share corners with four equivalent Yb(1)U12 cuboctahedra, corners with fourteen equivalent U(1)Yb4U8 cuboctahedra, edges with six equivalent Yb(1)U12 cuboctahedra, edges with twelve equivalent U(1)Yb4U8 cuboctahedra, faces with four equivalent Yb(1)U12 cuboctahedra, and faces with sixteen equivalent U(1)Yb4U8 cuboctahedra. Yb(1) is bonded to twelve equivalent U(1) atoms to form YbU12 cuboctahedra that share corners with six equivalent Yb(1)U12 cuboctahedra, corners with twelve equivalent U(1)Yb4U8 cuboctahedra, edges with eighteen equivalent U(1)Yb4U8 cuboctahedra, faces with eight equivalent Yb(1)U12 cuboctahedra, and faces with twelve equivalent U(1)Yb4U8 cuboctahedra.
U3Yb crystallizes in the hexagonal P6_3/mmc space group. U(1) is bonded to eight equivalent U(1) and four equivalent Yb(1) atoms to form distorted UYb4U8 cuboctahedra that share corners with four equivalent Yb(1)U12 cuboctahedra, corners with fourteen equivalent U(1)Yb4U8 cuboctahedra, edges with six equivalent Yb(1)U12 cuboctahedra, edges with twelve equivalent U(1)Yb4U8 cuboctahedra, faces with four equivalent Yb(1)U12 cuboctahedra, and faces with sixteen equivalent U(1)Yb4U8 cuboctahedra. There are a spread of U(1)-U(1) bond distances ranging from 2.78-3.56 Å. There are two shorter (3.18 Å) and two longer (3.35 Å) U(1)-Yb(1) bond lengths. Yb(1) is bonded to twelve equivalent U(1) atoms to form YbU12 cuboctahedra that share corners with six equivalent Yb(1)U12 cuboctahedra, corners with twelve equivalent U(1)Yb4U8 cuboctahedra, edges with eighteen equivalent U(1)Yb4U8 cuboctahedra, faces with eight equivalent Yb(1)U12 cuboctahedra, and faces with twelve equivalent U(1)Yb4U8 cuboctahedra.