Ethyl­enedi­ammonium sodium tetra­kis­[bis­(ethyl­enedi­amine-κ²N,N′)(oxalato-κ²O¹,O²)cobalt(III)] [penta­hydrogen di(phosphato­octa­deca­tungstate)] tetra­deca­hydrate

The title compound, Na(C₂H₁₀N₂)[Co(C₂O₄)(C₂H₈N₂)₂]₄[H₅(P₂W₁₈O₆₂)₂]·14H₂O, prepared under hydro­thermal conditions, consists of two Dawson-type [P₂W₁₈O₆₂]⁶⁻ anions, four isolated [Co(en)₂(ox)]⁺ cations (en = ethyl­enedi­amine and ox = oxalate), one Na⁺ cation, one [H₂en]²⁺ cation, and a number of ordered (14) and disordered solvent water mol­ecules. The [P₂W₁₈O₆₂]⁶⁻ polyoxidometalate anion has site symmetry 1 and contains two structurally distinct types of W atoms: viz. six W atoms on vertical pseudo-mirror planes grouped in two sets of three, and 12 equatorial W atoms that do not lie in the pseudo-mirror planes grouped in two sets of six. In each [Co(en)₂(ox)]⁺ cation, the Co^III ion is coordinated by four N atoms from two en ligands and two O atoms from the ox ligands, completing a distorted octa­hedral structure. The sodium cation lies on an inversion centre and additionally links the complex cations and anions. In the crystal, the various units are linked by N—H...O and O—H...O hydrogen bonds, which together with C—H...O hydrogen bonds form a three-dimensional structure. The contribution of a region of disordered electron density, possibly highly disordered solvent water mol­ecules, to the scattering was removed with the SQUEEZE option of PLATON [Spek (2009). Acta Cryst. D65, 148–155]. To equilibrate the charges five H⁺ ions have been added to the polyoxidometalate. These H⁺ ions and the disordered solvent contribution were not included in the reported mol­ecular weight and density.