Synthesis and structure of a molybdovanadate with the asymmetric [Mo4V5)27]5− anion

(Hmorph)6[Mo4V5O27]CL · H2O (morph = morpholine) has been synthesized from ammonium vanadate and sodium molybdate in acidic aqueous solution by adding morpholine and its structure determined by single-crystal X-ray analysis. The structure of the molybdovanadate anion is a hybrid of the decavanadate structure in the vanadium-rich region and of the β-octamolybdate structure in the molybdenum-rich region. It is built up of nine edge-sharing MO6 octahedra, but with a random distribution of molybdenum and vanadium atoms in two “capping” metal atom sites in the vanadium-rich region.