Mg(WO2)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(4), two equivalent O(6), and two equivalent O(7) atoms to form MgO5 square pyramids that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(3)O6 octahedra, corners with two equivalent W(4)O6 octahedra,  an edgeedge with one W(4)O6 octahedra, edges with two equivalent W(1)O6 octahedra, edges with two equivalent Mg(1)O5 square pyramids, and  a faceface with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-55°. There are four inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form WO6 octahedra that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(3)O6 octahedra, edges with two equivalent W(1)O6 octahedra, edges with two equivalent W(4)O6 octahedra, and edges with two equivalent Mg(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 48-54°. In the second W site, W(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form distorted WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(4)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, edges with two equivalent W(2)O6 octahedra, edges with two equivalent W(3)O6 octahedra, and  a faceface with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 48-55°. In the third W site, W(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(4)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, edges with two equivalent W(2)O6 octahedra, and edges with two equivalent W(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-54°. In the fourth W site, W(4) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form WO6 octahedra that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(3)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, edges with two equivalent W(1)O6 octahedra, edges with two equivalent W(4)O6 octahedra, and  an edgeedge with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 51-55°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one W(3) and two equivalent W(4) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one W(1) and two equivalent W(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one W(4) and two equivalent W(2) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one W(2), and two equivalent W(1) atoms to form distorted OMgW3 trigonal pyramids that share corners with two equivalent O(4)MgW3 trigonal pyramids and edges with two equivalent O(7)Mg2W3 square pyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one W(4) and two equivalent W(1) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one W(3), and two equivalent W(2) atoms. In the seventh O site, O(7) is bonded to two equivalent Mg(1), one W(1), and two equivalent W(4) atoms to form OMg2W3 square pyramids that share edges with two equivalent O(7)Mg2W3 square pyramids and edges with two equivalent O(4)MgW3 trigonal pyramids. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one W(2) and two equivalent W(3) atoms.
Mg(WO2)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(4), two equivalent O(6), and two equivalent O(7) atoms to form MgO5 square pyramids that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(3)O6 octahedra, corners with two equivalent W(4)O6 octahedra,  an edgeedge with one W(4)O6 octahedra, edges with two equivalent W(1)O6 octahedra, edges with two equivalent Mg(1)O5 square pyramids, and  a faceface with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-55°. The Mg(1)-O(4) bond length is 2.13 Å. There is one shorter (2.18 Å) and one longer (2.24 Å) Mg(1)-O(6) bond length. There is one shorter (2.15 Å) and one longer (2.19 Å) Mg(1)-O(7) bond length. There are four inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form WO6 octahedra that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(3)O6 octahedra, edges with two equivalent W(1)O6 octahedra, edges with two equivalent W(4)O6 octahedra, and edges with two equivalent Mg(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 48-54°. The W(1)-O(2) bond length is 2.03 Å. The W(1)-O(7) bond length is 2.23 Å. There is one shorter (2.07 Å) and one longer (2.17 Å) W(1)-O(4) bond length. There is one shorter (2.02 Å) and one longer (2.12 Å) W(1)-O(5) bond length. In the second W site, W(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form distorted WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(4)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, edges with two equivalent W(2)O6 octahedra, edges with two equivalent W(3)O6 octahedra, and  a faceface with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 48-55°. The W(2)-O(4) bond length is 2.18 Å. The W(2)-O(8) bond length is 2.13 Å. Both W(2)-O(3) bond lengths are 2.09 Å. There is one shorter (2.38 Å) and one longer (2.39 Å) W(2)-O(6) bond length. In the third W site, W(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form WO6 octahedra that share corners with two equivalent W(1)O6 octahedra, corners with two equivalent W(4)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, edges with two equivalent W(2)O6 octahedra, and edges with two equivalent W(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-54°. The W(3)-O(1) bond length is 2.00 Å. The W(3)-O(6) bond length is 2.20 Å. There is one shorter (2.12 Å) and one longer (2.16 Å) W(3)-O(2) bond length. There is one shorter (2.07 Å) and one longer (2.10 Å) W(3)-O(8) bond length. In the fourth W site, W(4) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form WO6 octahedra that share corners with two equivalent W(2)O6 octahedra, corners with two equivalent W(3)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, edges with two equivalent W(1)O6 octahedra, edges with two equivalent W(4)O6 octahedra, and  an edgeedge with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 51-55°. The W(4)-O(3) bond length is 2.12 Å. The W(4)-O(5) bond length is 2.21 Å. Both W(4)-O(1) bond lengths are 2.11 Å. There is one shorter (2.32 Å) and one longer (2.33 Å) W(4)-O(7) bond length. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one W(3) and two equivalent W(4) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one W(1) and two equivalent W(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one W(4) and two equivalent W(2) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one W(2), and two equivalent W(1) atoms to form distorted OMgW3 trigonal pyramids that share corners with two equivalent O(4)MgW3 trigonal pyramids and edges with two equivalent O(7)Mg2W3 square pyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one W(4) and two equivalent W(1) atoms. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one W(3), and two equivalent W(2) atoms. In the seventh O site, O(7) is bonded to two equivalent Mg(1), one W(1), and two equivalent W(4) atoms to form OMg2W3 square pyramids that share edges with two equivalent O(7)Mg2W3 square pyramids and edges with two equivalent O(4)MgW3 trigonal pyramids. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one W(2) and two equivalent W(3) atoms.