Ethylenediammonium sodium tetrakis-[bis(ethylenediamine-kappa N-2,N ')(oxalato-kappa O-2(1),O-2)cobalt(III)] [pentahydrogen di(phosphatooctadecatungstate)] tetradecahydrate

The title compound, Na(C2H10N2)[Co(C2O4)(C2H8N2)(2)](4)-[H-5(P2W18O62)(2)]center dot 14H(2)O, 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 [H(2)en](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 center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds, which together with C-H center dot center dot center dot 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.