Mg3W 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 W(1) atoms to form distorted MgMg8W4 cuboctahedra that share corners with eight equivalent W(1)Mg10W2 cuboctahedra, corners with ten equivalent Mg(1)Mg8W4 cuboctahedra, edges with two equivalent Mg(1)Mg8W4 cuboctahedra, edges with four equivalent W(1)Mg10W2 cuboctahedra, faces with four equivalent Mg(1)Mg8W4 cuboctahedra, and faces with four equivalent W(1)Mg10W2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and four equivalent W(1) atoms. In the third Mg site, Mg(3) is bonded in a distorted bent 120 degrees geometry to four equivalent Mg(1) and two equivalent W(1) atoms. W(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent W(1) atoms to form distorted WMg10W2 cuboctahedra that share corners with eight equivalent Mg(1)Mg8W4 cuboctahedra, corners with ten equivalent W(1)Mg10W2 cuboctahedra, edges with two equivalent W(1)Mg10W2 cuboctahedra, edges with four equivalent Mg(1)Mg8W4 cuboctahedra, faces with four equivalent Mg(1)Mg8W4 cuboctahedra, and faces with four equivalent W(1)Mg10W2 cuboctahedra.
Mg3W 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 W(1) atoms to form distorted MgMg8W4 cuboctahedra that share corners with eight equivalent W(1)Mg10W2 cuboctahedra, corners with ten equivalent Mg(1)Mg8W4 cuboctahedra, edges with two equivalent Mg(1)Mg8W4 cuboctahedra, edges with four equivalent W(1)Mg10W2 cuboctahedra, faces with four equivalent Mg(1)Mg8W4 cuboctahedra, and faces with four equivalent W(1)Mg10W2 cuboctahedra. Both Mg(1)-Mg(1) bond lengths are 2.85 Å. Both Mg(1)-Mg(2) bond lengths are 3.03 Å. All Mg(1)-Mg(3) bond lengths are 3.06 Å. There are two shorter (3.05 Å) and two longer (3.06 Å) Mg(1)-W(1) bond lengths. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and four equivalent W(1) atoms. All Mg(2)-W(1) bond lengths are 2.99 Å. In the third Mg site, Mg(3) is bonded in a distorted bent 120 degrees geometry to four equivalent Mg(1) and two equivalent W(1) atoms. Both Mg(3)-W(1) bond lengths are 2.91 Å. W(1) is bonded to two equivalent Mg(3), four equivalent Mg(1), four equivalent Mg(2), and two equivalent W(1) atoms to form distorted WMg10W2 cuboctahedra that share corners with eight equivalent Mg(1)Mg8W4 cuboctahedra, corners with ten equivalent W(1)Mg10W2 cuboctahedra, edges with two equivalent W(1)Mg10W2 cuboctahedra, edges with four equivalent Mg(1)Mg8W4 cuboctahedra, faces with four equivalent Mg(1)Mg8W4 cuboctahedra, and faces with four equivalent W(1)Mg10W2 cuboctahedra. Both W(1)-W(1) bond lengths are 2.85 Å.