A novel zirconium polyoxometalate compound: (NH(4))(9)[Zr(2)(mu-OH)(H(2)O)(2)(AsOH)(2)(AsW(7)O(28))(AsW(10)O(36))].26H(2)O.

The crystal structure of the title compound, nonaammonium (arsenic decatungstido)(arsenic heptatungstido)diaqua-mu-hydroxo-(hydroxyarsenido)dizirconium hexacosahydrate, which was obtained from the reaction of NaAs(4)W(40)O(140) with Zr(IV), has been determined. The anionic complex consists of two hydroxyl-bridged seven-coordinate capped trigonal-prismatic zirconium ions, which are bonded to an AsW(10)O(36) anion and to an AsW(7)O(28) anion that has two AsOH capping units. The asymmetric unit contains half of the complex, with one crystallographically independent Zr atom. Crystallographic m symmetry imposed by the monoclinic C2/m space group gives rise to the asymmetric unit comprising half of the complex with one crystallographically independent Zr atom.