PREPARATION AND SOME PROPERTIES OF GAMMA-ZIRCONIUM PHOSPHATE BENZENEPHOSPHONATE

Gamma-Zirconium phosphate benzenephosphonate was prepared by exchanging the interlayer H2PO4- group of gamma-zirconium phosphate dihydrate with the C6H5PO2(OH)- group of benzenephosphonic acid. The replacement was performed by heating for 24 h a suspension of gamma-Zr phosphate (1 g) in 100 ml of 1 M benzenephosphonic acid, either in water (at 80-degrees-C) or in 50% aq acetone (at the refluxing temperature). The chemical and thermal analysis, together with the P-31 liquid-state NMR spectroscopic and X-rav powder diffraction data, confirm the product to have the composition of gamma-ZrPO4-(H2PO4)0.33(C6H5PO2OH)0.67.nH2O (d = 15.35 +/- 0.05 angstrom for 1 < n < 2 and d = 13.26 angstrom for n = 0). The partial interchange of H2PO4-/C6H5PO2(OH)- groups seems to be due to the steric hindrance of the large C6H5 radicals in the interlayer region; some considerations on the layer structure of this compound are, therefore, reported. The high-temperature X-ray diffraction and TG data show that the compound is quite stable up to approximately 270-degrees-C. Some ion-exchange and intercalation properties of this compound have been investigated and are discussed.