AlMg3 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 Al(1) atoms to form distorted MgMg8Al4 cuboctahedra that share corners with ten equivalent Mg(1)Mg8Al4 cuboctahedra, edges with two equivalent Mg(1)Mg8Al4 cuboctahedra, edges with four equivalent Mg(2)Mg8Al4 cuboctahedra, edges with eight equivalent Mg(3)Mg10Al2 cuboctahedra, faces with four equivalent Mg(3)Mg10Al2 cuboctahedra, faces with four equivalent Mg(1)Mg8Al4 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Al4 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 Al(1) atoms to form distorted MgMg8Al4 cuboctahedra that share corners with eight equivalent Mg(3)Mg10Al2 cuboctahedra, corners with ten equivalent Mg(2)Mg8Al4 cuboctahedra, edges with two equivalent Mg(2)Mg8Al4 cuboctahedra, edges with four equivalent Mg(3)Mg10Al2 cuboctahedra, edges with four equivalent Mg(1)Mg8Al4 cuboctahedra, faces with four equivalent Mg(3)Mg10Al2 cuboctahedra, faces with four equivalent Mg(2)Mg8Al4 cuboctahedra, and faces with eight equivalent Mg(1)Mg8Al4 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 Al(1) atoms to form distorted MgMg10Al2 cuboctahedra that share corners with eight equivalent Mg(2)Mg8Al4 cuboctahedra, corners with ten equivalent Mg(3)Mg10Al2 cuboctahedra, edges with two equivalent Mg(3)Mg10Al2 cuboctahedra, edges with four equivalent Mg(2)Mg8Al4 cuboctahedra, edges with eight equivalent Mg(1)Mg8Al4 cuboctahedra, faces with four equivalent Mg(3)Mg10Al2 cuboctahedra, faces with four equivalent Mg(1)Mg8Al4 cuboctahedra, and faces with four equivalent Mg(2)Mg8Al4 cuboctahedra. Al(1) is bonded in a 10-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms.
AlMg3 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 Al(1) atoms to form distorted MgMg8Al4 cuboctahedra that share corners with ten equivalent Mg(1)Mg8Al4 cuboctahedra, edges with two equivalent Mg(1)Mg8Al4 cuboctahedra, edges with four equivalent Mg(2)Mg8Al4 cuboctahedra, edges with eight equivalent Mg(3)Mg10Al2 cuboctahedra, faces with four equivalent Mg(3)Mg10Al2 cuboctahedra, faces with four equivalent Mg(1)Mg8Al4 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Al4 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 3.15 Å. Both Mg(1)-Mg(2) bond lengths are 3.06 Å. All Mg(1)-Mg(3) bond lengths are 3.04 Å. There are two shorter (3.09 Å) and two longer (3.10 Å) Mg(1)-Al(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 Al(1) atoms to form distorted MgMg8Al4 cuboctahedra that share corners with eight equivalent Mg(3)Mg10Al2 cuboctahedra, corners with ten equivalent Mg(2)Mg8Al4 cuboctahedra, edges with two equivalent Mg(2)Mg8Al4 cuboctahedra, edges with four equivalent Mg(3)Mg10Al2 cuboctahedra, edges with four equivalent Mg(1)Mg8Al4 cuboctahedra, faces with four equivalent Mg(3)Mg10Al2 cuboctahedra, faces with four equivalent Mg(2)Mg8Al4 cuboctahedra, and faces with eight equivalent Mg(1)Mg8Al4 cuboctahedra. Both Mg(2)-Mg(2) bond lengths are 3.15 Å. There are two shorter (3.04 Å) and two longer (3.16 Å) Mg(2)-Mg(3) bond lengths. All Mg(2)-Al(1) bond lengths are 3.03 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 Al(1) atoms to form distorted MgMg10Al2 cuboctahedra that share corners with eight equivalent Mg(2)Mg8Al4 cuboctahedra, corners with ten equivalent Mg(3)Mg10Al2 cuboctahedra, edges with two equivalent Mg(3)Mg10Al2 cuboctahedra, edges with four equivalent Mg(2)Mg8Al4 cuboctahedra, edges with eight equivalent Mg(1)Mg8Al4 cuboctahedra, faces with four equivalent Mg(3)Mg10Al2 cuboctahedra, faces with four equivalent Mg(1)Mg8Al4 cuboctahedra, and faces with four equivalent Mg(2)Mg8Al4 cuboctahedra. Both Mg(3)-Mg(3) bond lengths are 3.15 Å. Both Mg(3)-Al(1) bond lengths are 3.01 Å. Al(1) is bonded in a 10-coordinate geometry to two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms.