Crystal structure of tetra­guanidinium [hexa­hydrogen hexa­arsenato(V)tetra­vanadate(V)] tetra­hydrate

The complete polyoxidometallate anion in the title compound, (CH(6)N(3))(4)[H(6)V(4)As(6)O(30)]·4H(2)O, is generated by crystallographic inversion symmetry. The polyhedral building units are distorted VO(6) octa­hedra and AsO(3)OH tetra­hedra. The VO(6) units feature a short formal V=O double bond and are linked by a common edge. Two such V(2)O(6) double octahedral units are linked by four isolated AsO(3)OH tetra­hedra to complete the anion, which features two inter­nal O—H⋯O hydrogen bonds. In the crystal, O—H⋯O hydrogen bonds between the polyoxidometallate anions generate (01-1) sheets. The sheets are connected by cation-to-cluster N—H⋯O hydrogen bonds, and cation-to-water N—H⋯O links also occur. The O atom of one of the water mol­ecules is disordered over two sites in a 0.703 (17):0.297 (17) ratio.