Mg3V crystallizes in the orthorhombic Pmm2 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), four equivalent Mg(3), and four equivalent V(1) atoms to form MgMg8V4 cuboctahedra that share corners with eight equivalent V(1)Mg10V2 cuboctahedra, corners with ten equivalent Mg(1)Mg8V4 cuboctahedra, edges with two equivalent Mg(1)Mg8V4 cuboctahedra, edges with four equivalent Mg(2)Mg8V4 cuboctahedra, edges with four equivalent V(1)Mg10V2 cuboctahedra, edges with eight equivalent Mg(3)Mg10V2 cuboctahedra, faces with four equivalent Mg(3)Mg10V2 cuboctahedra, faces with four equivalent Mg(1)Mg8V4 cuboctahedra, faces with four equivalent V(1)Mg10V2 cuboctahedra, and faces with eight equivalent Mg(2)Mg8V4 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), four equivalent Mg(3), and four equivalent V(1) atoms to form distorted MgMg8V4 cuboctahedra that share corners with eight equivalent Mg(3)Mg10V2 cuboctahedra, corners with ten equivalent Mg(2)Mg8V4 cuboctahedra, edges with two equivalent Mg(2)Mg8V4 cuboctahedra, edges with four equivalent Mg(3)Mg10V2 cuboctahedra, edges with four equivalent Mg(1)Mg8V4 cuboctahedra, edges with eight equivalent V(1)Mg10V2 cuboctahedra, faces with four equivalent Mg(3)Mg10V2 cuboctahedra, faces with four equivalent Mg(2)Mg8V4 cuboctahedra, faces with four equivalent V(1)Mg10V2 cuboctahedra, and faces with eight equivalent Mg(1)Mg8V4 cuboctahedra. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent V(1) atoms to form distorted MgMg10V2 cuboctahedra that share corners with eight equivalent Mg(2)Mg8V4 cuboctahedra, corners with ten equivalent Mg(3)Mg10V2 cuboctahedra, edges with two equivalent Mg(3)Mg10V2 cuboctahedra, edges with four equivalent Mg(2)Mg8V4 cuboctahedra, edges with four equivalent V(1)Mg10V2 cuboctahedra, edges with eight equivalent Mg(1)Mg8V4 cuboctahedra, faces with four equivalent Mg(3)Mg10V2 cuboctahedra, faces with four equivalent Mg(1)Mg8V4 cuboctahedra, faces with four equivalent Mg(2)Mg8V4 cuboctahedra, and faces with eight equivalent V(1)Mg10V2 cuboctahedra. V(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent V(1) atoms to form VMg10V2 cuboctahedra that share corners with eight equivalent Mg(1)Mg8V4 cuboctahedra, corners with ten equivalent V(1)Mg10V2 cuboctahedra, edges with two equivalent V(1)Mg10V2 cuboctahedra, edges with four equivalent Mg(3)Mg10V2 cuboctahedra, edges with four equivalent Mg(1)Mg8V4 cuboctahedra, edges with eight equivalent Mg(2)Mg8V4 cuboctahedra, faces with four equivalent Mg(1)Mg8V4 cuboctahedra, faces with four equivalent Mg(2)Mg8V4 cuboctahedra, faces with four equivalent V(1)Mg10V2 cuboctahedra, and faces with eight equivalent Mg(3)Mg10V2 cuboctahedra.
Mg3V crystallizes in the orthorhombic Pmm2 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), four equivalent Mg(3), and four equivalent V(1) atoms to form MgMg8V4 cuboctahedra that share corners with eight equivalent V(1)Mg10V2 cuboctahedra, corners with ten equivalent Mg(1)Mg8V4 cuboctahedra, edges with two equivalent Mg(1)Mg8V4 cuboctahedra, edges with four equivalent Mg(2)Mg8V4 cuboctahedra, edges with four equivalent V(1)Mg10V2 cuboctahedra, edges with eight equivalent Mg(3)Mg10V2 cuboctahedra, faces with four equivalent Mg(3)Mg10V2 cuboctahedra, faces with four equivalent Mg(1)Mg8V4 cuboctahedra, faces with four equivalent V(1)Mg10V2 cuboctahedra, and faces with eight equivalent Mg(2)Mg8V4 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 3.00 Å. Both Mg(1)-Mg(2) bond lengths are 3.05 Å. All Mg(1)-Mg(3) bond lengths are 3.10 Å. There are two shorter (3.10 Å) and two longer (3.11 Å) Mg(1)-V(1) bond lengths. In the second Mg site, Mg(2) is bonded to two equivalent Mg(1), two equivalent Mg(2), four equivalent Mg(3), and four equivalent V(1) atoms to form distorted MgMg8V4 cuboctahedra that share corners with eight equivalent Mg(3)Mg10V2 cuboctahedra, corners with ten equivalent Mg(2)Mg8V4 cuboctahedra, edges with two equivalent Mg(2)Mg8V4 cuboctahedra, edges with four equivalent Mg(3)Mg10V2 cuboctahedra, edges with four equivalent Mg(1)Mg8V4 cuboctahedra, edges with eight equivalent V(1)Mg10V2 cuboctahedra, faces with four equivalent Mg(3)Mg10V2 cuboctahedra, faces with four equivalent Mg(2)Mg8V4 cuboctahedra, faces with four equivalent V(1)Mg10V2 cuboctahedra, and faces with eight equivalent Mg(1)Mg8V4 cuboctahedra. Both Mg(2)-Mg(2) bond lengths are 3.00 Å. There are two shorter (3.01 Å) and two longer (3.20 Å) Mg(2)-Mg(3) bond lengths. All Mg(2)-V(1) bond lengths are 3.06 Å. In the third Mg site, Mg(3) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent V(1) atoms to form distorted MgMg10V2 cuboctahedra that share corners with eight equivalent Mg(2)Mg8V4 cuboctahedra, corners with ten equivalent Mg(3)Mg10V2 cuboctahedra, edges with two equivalent Mg(3)Mg10V2 cuboctahedra, edges with four equivalent Mg(2)Mg8V4 cuboctahedra, edges with four equivalent V(1)Mg10V2 cuboctahedra, edges with eight equivalent Mg(1)Mg8V4 cuboctahedra, faces with four equivalent Mg(3)Mg10V2 cuboctahedra, faces with four equivalent Mg(1)Mg8V4 cuboctahedra, faces with four equivalent Mg(2)Mg8V4 cuboctahedra, and faces with eight equivalent V(1)Mg10V2 cuboctahedra. Both Mg(3)-Mg(3) bond lengths are 3.00 Å. Both Mg(3)-V(1) bond lengths are 2.99 Å. V(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent V(1) atoms to form VMg10V2 cuboctahedra that share corners with eight equivalent Mg(1)Mg8V4 cuboctahedra, corners with ten equivalent V(1)Mg10V2 cuboctahedra, edges with two equivalent V(1)Mg10V2 cuboctahedra, edges with four equivalent Mg(3)Mg10V2 cuboctahedra, edges with four equivalent Mg(1)Mg8V4 cuboctahedra, edges with eight equivalent Mg(2)Mg8V4 cuboctahedra, faces with four equivalent Mg(1)Mg8V4 cuboctahedra, faces with four equivalent Mg(2)Mg8V4 cuboctahedra, faces with four equivalent V(1)Mg10V2 cuboctahedra, and faces with eight equivalent Mg(3)Mg10V2 cuboctahedra. Both V(1)-V(1) bond lengths are 3.00 Å.