MgWO2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), two equivalent O(3), and two equivalent O(4) atoms to form MgO5 square pyramids that share corners with two equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, edges with three 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 5-50°. In the second Mg site, Mg(2) is bonded in a rectangular see-saw-like geometry to one O(3), one O(4), and two equivalent O(2) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form WO6 octahedra that share corners with four equivalent W(2)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, edges with four equivalent W(1)O6 octahedra, and edges with three equivalent Mg(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 48-52°. In the second W site, W(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form distorted WO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent Mg(1)O5 square pyramids, edges with four equivalent W(2)O6 octahedra, and  a faceface with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 48-52°. There are four inequivalent O sites. In the first O site, O(1) 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(3)Mg3W3 octahedra, corners with two equivalent O(1)MgW3 trigonal pyramids, and edges with three equivalent O(3)Mg3W3 octahedra. The corner-sharing octahedral tilt angles are 12°. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Mg(2), one W(1), and two equivalent W(2) atoms. In the third O site, O(3) is bonded to one Mg(2), two equivalent Mg(1), and three equivalent W(1) atoms to form OMg3W3 octahedra that share corners with two equivalent O(1)MgW3 trigonal pyramids, edges with four equivalent O(3)Mg3W3 octahedra, and edges with three equivalent O(1)MgW3 trigonal pyramids. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Mg(2), two equivalent Mg(1), and three equivalent W(2) atoms.
MgWO2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), two equivalent O(3), and two equivalent O(4) atoms to form MgO5 square pyramids that share corners with two equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, edges with three 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 5-50°. The Mg(1)-O(1) bond length is 2.08 Å. Both Mg(1)-O(3) bond lengths are 2.32 Å. Both Mg(1)-O(4) bond lengths are 2.18 Å. In the second Mg site, Mg(2) is bonded in a rectangular see-saw-like geometry to one O(3), one O(4), and two equivalent O(2) atoms. The Mg(2)-O(3) bond length is 2.19 Å. The Mg(2)-O(4) bond length is 2.20 Å. Both Mg(2)-O(2) bond lengths are 2.16 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form WO6 octahedra that share corners with four equivalent W(2)O6 octahedra, corners with two equivalent Mg(1)O5 square pyramids, edges with four equivalent W(1)O6 octahedra, and edges with three equivalent Mg(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 48-52°. The W(1)-O(2) bond length is 2.20 Å. Both W(1)-O(1) bond lengths are 2.14 Å. There are two shorter (2.28 Å) and one longer (2.30 Å) W(1)-O(3) bond length. In the second W site, W(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form distorted WO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent Mg(1)O5 square pyramids, edges with four equivalent W(2)O6 octahedra, and  a faceface with one Mg(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 48-52°. The W(2)-O(1) bond length is 2.17 Å. Both W(2)-O(2) bond lengths are 2.37 Å. There is one shorter (2.27 Å) and two longer (2.50 Å) W(2)-O(4) bond lengths. There are four inequivalent O sites. In the first O site, O(1) 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(3)Mg3W3 octahedra, corners with two equivalent O(1)MgW3 trigonal pyramids, and edges with three equivalent O(3)Mg3W3 octahedra. The corner-sharing octahedral tilt angles are 12°. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Mg(2), one W(1), and two equivalent W(2) atoms. In the third O site, O(3) is bonded to one Mg(2), two equivalent Mg(1), and three equivalent W(1) atoms to form OMg3W3 octahedra that share corners with two equivalent O(1)MgW3 trigonal pyramids, edges with four equivalent O(3)Mg3W3 octahedra, and edges with three equivalent O(1)MgW3 trigonal pyramids. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Mg(2), two equivalent Mg(1), and three equivalent W(2) atoms.