Ca(WO2)4 crystallizes in the trigonal R-3m space group. Ca(1) is bonded to six equivalent O(1) atoms to form CaO6 octahedra that share corners with six equivalent W(2)O6 octahedra and edges with six equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are two inequivalent W sites. In the first W site, W(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form WO6 octahedra that share edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent W(2)O6 octahedra, and edges with four equivalent W(1)O6 octahedra. In the second W site, W(2) is bonded to six equivalent O(1) atoms to form WO6 octahedra that share corners with six equivalent Ca(1)O6 octahedra and edges with six equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one W(2), and two equivalent W(1) atoms. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to three equivalent W(1) atoms.
Ca(WO2)4 crystallizes in the trigonal R-3m space group. Ca(1) is bonded to six equivalent O(1) atoms to form CaO6 octahedra that share corners with six equivalent W(2)O6 octahedra and edges with six equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. All Ca(1)-O(1) bond lengths are 2.47 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form WO6 octahedra that share edges with two equivalent Ca(1)O6 octahedra, edges with two equivalent W(2)O6 octahedra, and edges with four equivalent W(1)O6 octahedra. Both W(1)-O(2) bond lengths are 2.10 Å. All W(1)-O(1) bond lengths are 2.14 Å. In the second W site, W(2) is bonded to six equivalent O(1) atoms to form WO6 octahedra that share corners with six equivalent Ca(1)O6 octahedra and edges with six equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles are 14°. All W(2)-O(1) bond lengths are 2.24 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Ca(1), one W(2), and two equivalent W(1) atoms. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to three equivalent W(1) atoms.