The cyclo-tetra­phosphate Cd(2)P(4)O(12), a member of the isotypic series M (2)P(4)O(12) (M = Mg, Mn, Fe, Co, Ni, Cu)

The title compound, Cd(2)P(4)O(12), dicadmium cyclo-tetra­phosphate, crystallizes isotypically with the members of the series M (II) (2)P(4)O(12), where M = Mg, Mn, Fe, Co, Ni or Cu. Two CdO(6) octa­hedra, one with 2 and one with [Image: see text] symmetry, share corners with the centrosymmetric P(4)O(12) (4−) ring anion that is built up from four corner-sharing PO(4) tetra­hedra. The isolated ring anions are arranged in layers parallel to (10[Image: see text]) with the CdO(6) octa­hedra situated between these layers. The main difference between the individual M (II) (2)P(4)O(12) structures pertains to the different sizes of the MO(6) octa­hedra whereas the geometric parameters of all cyclo-P(4)O(12) (4−) anions are very similar.