[H3NNH3](2)K2MnMo9O32 center dot(NH3)center dot 3H(2)O: synthesis and crystal structure determination of a novel heteropolyoxometallate related to the Waugh structure

A novel hetrropolyoxometallate with the formula [H3NNH3](2)K2MnMo9O32.(NH3) . 3H(2)O has been prepared in water solution. The crystal structure of the title compound was determined by the single-crystal method. This new mixed metal anionic complex crystallizes in the rhombohedral space group R3 (No. 146) with a = b = 15.873(5), c = 12.344(6) Angstrom, gamma = 120 degrees. T he disordered structure contains three molecules in the unit cell. Full-mat rix least-squares refinements of the title complex yielded final reliabilit y (R) factors of 0.0356 (Rw = 0.0868) with a goodness-of-fit (GOF, Sigma(2) ) value of 1.099 based on 1430 [I > 2 sigma(I)] observed reflections. All M o and Mn atoms are six-coordinated octahedrally to form a Mn-centered cage with a Mo9O32 group as the framework. (C) 1999 Elsevier Science S.A. All ri ghts reserved.