MgU crystallizes in the orthorhombic Pmma space group. Mg(1) is bonded to four equivalent Mg(1) and eight equivalent U(1) atoms to form distorted MgMg4U8 cuboctahedra that share corners with eight equivalent U(1)Mg8U4 cuboctahedra, corners with ten equivalent Mg(1)Mg4U8 cuboctahedra, edges with six equivalent Mg(1)Mg4U8 cuboctahedra, edges with twelve equivalent U(1)Mg8U4 cuboctahedra, faces with eight equivalent U(1)Mg8U4 cuboctahedra, and faces with twelve equivalent Mg(1)Mg4U8 cuboctahedra. U(1) is bonded to eight equivalent Mg(1) and four equivalent U(1) atoms to form distorted UMg8U4 cuboctahedra that share corners with eight equivalent Mg(1)Mg4U8 cuboctahedra, corners with ten equivalent U(1)Mg8U4 cuboctahedra, edges with six equivalent U(1)Mg8U4 cuboctahedra, edges with twelve equivalent Mg(1)Mg4U8 cuboctahedra, faces with eight equivalent Mg(1)Mg4U8 cuboctahedra, and faces with twelve equivalent U(1)Mg8U4 cuboctahedra.
MgU crystallizes in the orthorhombic Pmma space group. Mg(1) is bonded to four equivalent Mg(1) and eight equivalent U(1) atoms to form distorted MgMg4U8 cuboctahedra that share corners with eight equivalent U(1)Mg8U4 cuboctahedra, corners with ten equivalent Mg(1)Mg4U8 cuboctahedra, edges with six equivalent Mg(1)Mg4U8 cuboctahedra, edges with twelve equivalent U(1)Mg8U4 cuboctahedra, faces with eight equivalent U(1)Mg8U4 cuboctahedra, and faces with twelve equivalent Mg(1)Mg4U8 cuboctahedra. There are two shorter (2.80 Å) and two longer (2.81 Å) Mg(1)-Mg(1) bond lengths. There are a spread of Mg(1)-U(1) bond distances ranging from 3.24-3.56 Å. U(1) is bonded to eight equivalent Mg(1) and four equivalent U(1) atoms to form distorted UMg8U4 cuboctahedra that share corners with eight equivalent Mg(1)Mg4U8 cuboctahedra, corners with ten equivalent U(1)Mg8U4 cuboctahedra, edges with six equivalent U(1)Mg8U4 cuboctahedra, edges with twelve equivalent Mg(1)Mg4U8 cuboctahedra, faces with eight equivalent Mg(1)Mg4U8 cuboctahedra, and faces with twelve equivalent U(1)Mg8U4 cuboctahedra. There are two shorter (2.65 Å) and two longer (2.80 Å) U(1)-U(1) bond lengths.