ION-EXCHANGE AND PROTONIC SPECIES IN THE ANTIMONY HYDROGEN PHOSPHATE HSB(PO4)(2)CENTER-DOT-2H(2)O

It has been established from the incoherent inelastic neutron scattering spectra (IINS) that both the oxonium [H3O](+) and dioxonium [H5O2](+) ions are present in the antimony hydrogen phosphate H1Sb(PO4)(2).2H(2)O, written as H1SbP2.2H(2)O. However, as the extent of hydration decreases as in H1SbP2.1.25H(2)O, the proportion of the oxonium [H3O](+) ion increases. MAS NMR indicates that the P-O-H+ group remains undissociated in the anhydrous form. The title compound is an efficient but unselective ion exchanger which is able to extract mono- and poly-valent aquo-cations, In addition, polyvalent complex cations may be exchanged directly without the need for a catalytic or delamination process. A relatively high temperature (266 degrees C) is needed to dehydrate Co[Sb(PO4)(2)](2).6H(2)O in which the cobalt appears to be bound to four water molecules with two axial oxygens from the macroanionic layers.