Tetra-ammonium diaqua-diperoxidoocta-molybdate(VI) tetra-hydrate.

The title compound (NH(4))(4)[Mo(8)O(24)(O(2))(2)(H(2)O)(2)]·4H(2)O, consists of an octa-molybdate cluster with a crystallographic centre of symmetry. The clusters pack in a cubic close packing arrangement defining channels containing water mol-ecules and ammonium cations, which exhibit hydrogen bonding with neighbouring clusters. Hydrogen bonding also exists between the coordinated water mol-ecules of one cluster with one of the O atoms of the peroxido fragment in a neighbouring cluster.