Tris(piperazinediium) phosphatododecamolybo(V,VI)phosphate

Abstract

The title compound, (C4H12N2)3[PMo12O40] or (H2pip)3[PMo12O40] (pip is piperazine), was prepared under hydrothermal conditions. The asymmetric unit contains one-sixth of a mixed-valent Mo(V,VI) pseudo-Keggin-type [PMo12O40]6− anion and half a piperazinediium cation, (H2pip)2+. The discrete Keggin-type [PMo12O40]6- anion has overline{3} site symmetry and the three (H2pip)2+ cations each have overline{1} site symmetry at the centres of the molecules. The central P atom is on special position overline{3}, which is a roto-inversion position and generates the disorder of the PO4 tetrahedron. Furthermore, six doubly bridging oxide groups are also disordered with an occupancy factor of 0.5 for each O atom. The anions and cations are linked by an extensive network of intermolecular N—H...O and C—H...O hydrogen bonds.