Solution Species and Crystal Structure of Zr(IV) Acetate.

Complex formation and the coordination of zirconium with acetic acid were investigated with Zr K-edge extended X-ray absorption fine structure spectroscopy (EXAFS) and single-crystal diffraction. Zr K-edge EXAFS spectra show that a stepwise increase of acetic acid in aqueous solution with 0.1 M Zr(IV) leads to a structural rearrangement from initial tetranuclear hydrolysis species [Zr(OH)(OH)] to a hexanuclear acetate species Zr(O)(OH)(CHCOO). The solution species Zr(O)(OH)(CHCOO) was preserved in crystals by slow evaporation of the aqueous solution. Single-crystal diffraction reveals an uncharged hexanuclear cluster in solid Zr(μ-O)(μ-OH)(CHCOO)·8.5HO. EXAFS measurements show that the structures of the hexanuclear zirconium acetate cluster in solution and the solid state are identical.