Mg6NbW crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Nb(1), and two equivalent W(1) atoms. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Nb(1) atoms to form distorted MgMg10Nb2 cuboctahedra that share corners with four equivalent Nb(1)Mg10W2 cuboctahedra, corners with six equivalent Mg(2)Mg10Nb2 cuboctahedra, edges with two equivalent Nb(1)Mg10W2 cuboctahedra, faces with two equivalent Mg(2)Mg10Nb2 cuboctahedra, faces with two equivalent Nb(1)Mg10W2 cuboctahedra, and faces with six equivalent W(1)Mg10Nb2 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Nb(1), and two equivalent W(1) atoms. In the fourth Mg site, Mg(4) is bonded in a distorted linear geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent W(1) atoms. Nb(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent W(1) atoms to form distorted NbMg10W2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Nb2 cuboctahedra, corners with six equivalent Nb(1)Mg10W2 cuboctahedra, edges with two equivalent Mg(2)Mg10Nb2 cuboctahedra, edges with four equivalent W(1)Mg10Nb2 cuboctahedra, faces with two equivalent Mg(2)Mg10Nb2 cuboctahedra, faces with two equivalent Nb(1)Mg10W2 cuboctahedra, and faces with two equivalent W(1)Mg10Nb2 cuboctahedra. W(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Nb(1) atoms to form distorted WMg10Nb2 cuboctahedra that share corners with six equivalent W(1)Mg10Nb2 cuboctahedra, edges with four equivalent Nb(1)Mg10W2 cuboctahedra, faces with two equivalent Nb(1)Mg10W2 cuboctahedra, faces with two equivalent W(1)Mg10Nb2 cuboctahedra, and faces with six equivalent Mg(2)Mg10Nb2 cuboctahedra.
Mg6NbW crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Nb(1), and two equivalent W(1) atoms. There is one shorter (2.90 Å) and one longer (3.14 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.05 Å) and one longer (3.21 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 2.93 Å. Both Mg(1)-Mg(4) bond lengths are 3.05 Å. There is one shorter (2.94 Å) and one longer (3.31 Å) Mg(1)-Nb(1) bond length. Both Mg(1)-W(1) bond lengths are 3.07 Å. In the second Mg site, Mg(2) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Nb(1) atoms to form distorted MgMg10Nb2 cuboctahedra that share corners with four equivalent Nb(1)Mg10W2 cuboctahedra, corners with six equivalent Mg(2)Mg10Nb2 cuboctahedra, edges with two equivalent Nb(1)Mg10W2 cuboctahedra, faces with two equivalent Mg(2)Mg10Nb2 cuboctahedra, faces with two equivalent Nb(1)Mg10W2 cuboctahedra, and faces with six equivalent W(1)Mg10Nb2 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 2.99 Å. All Mg(2)-Mg(3) bond lengths are 3.03 Å. Both Mg(2)-Nb(1) bond lengths are 3.03 Å. In the third Mg site, Mg(3) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Nb(1), and two equivalent W(1) atoms. There is one shorter (2.93 Å) and one longer (3.11 Å) Mg(3)-Mg(3) bond length. There is one shorter (3.07 Å) and one longer (3.19 Å) Mg(3)-Mg(4) bond length. Both Mg(3)-Nb(1) bond lengths are 3.08 Å. There is one shorter (2.96 Å) and one longer (3.29 Å) Mg(3)-W(1) bond length. In the fourth Mg site, Mg(4) is bonded in a distorted linear geometry to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent W(1) atoms. Both Mg(4)-W(1) bond lengths are 3.03 Å. Nb(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent W(1) atoms to form distorted NbMg10W2 cuboctahedra that share corners with four equivalent Mg(2)Mg10Nb2 cuboctahedra, corners with six equivalent Nb(1)Mg10W2 cuboctahedra, edges with two equivalent Mg(2)Mg10Nb2 cuboctahedra, edges with four equivalent W(1)Mg10Nb2 cuboctahedra, faces with two equivalent Mg(2)Mg10Nb2 cuboctahedra, faces with two equivalent Nb(1)Mg10W2 cuboctahedra, and faces with two equivalent W(1)Mg10Nb2 cuboctahedra. Both Nb(1)-W(1) bond lengths are 2.75 Å. W(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Nb(1) atoms to form distorted WMg10Nb2 cuboctahedra that share corners with six equivalent W(1)Mg10Nb2 cuboctahedra, edges with four equivalent Nb(1)Mg10W2 cuboctahedra, faces with two equivalent Nb(1)Mg10W2 cuboctahedra, faces with two equivalent W(1)Mg10Nb2 cuboctahedra, and faces with six equivalent Mg(2)Mg10Nb2 cuboctahedra.