A new Mo(III) cadmium diphosphate Cd5Mo2(P2O7)4

A Mo(III) cadmium diphosphate, Cd5Mo2(P2O7)4 has been synthesized for the first time. Its structure determination shows that the crystal chemistry of this new monoclinic phosphate is complex, due to the ability of cadmium to behave either as an interpolated cation, or as a building unit for the whole framework. Two descriptions of the structure can be proposed. The first one corresponds to a combination of a layer structure and an intersecting tunnel structure built up of MoO6 octahedra and P2O7 groups, with Cd2+ cations sitting in the tunnels and between the [Mo2P8O28] layers. The second description shows that CdO6 octahedra share edges, forming waving [CdO4] ribbons, which themselves share edges with MoO6 octahedra, and corners with P2O7 groups to form a rather close packed structure.