A new aqua-manganese(II) oxalate phosphate, Mn(C(2)O(4))Mn(3)(PO(4))(2)(H(2)O)(2).

The title salt, diaquatetra-manganese(II) oxalate bis[ortho-phos-phate(V)], Mn(4)(C(2)O(4))(PO(4))(2)(H(2)O)(2), was synthesized hydro-thermally and displays a three-dimensional framework structure. The asymmetric unit consists of two different Mn(II) centers, half of an oxalate anion, a phosphate group and a coordinated water mol-ecule. A crystallographic inversion center is located at the mid-point of the oxalate C-C bond. The distorted octa-hedral MnO(6) and the tetra-gonal pyramidal MnO(5) centers are linked through bridging oxalate and phosphate groups. The water mol-ecule also has a weaker bonding contact to the five-coordinate Mn atom, which consequently exhibits a distorted octa-hedral geometry and also bridges the independent Mn atoms. The water mol-ecule is a donor for intra- and inter-molecular O-H⋯O hydrogen bonds.