The physical chemistry of the compounds MIP(As)UO6 (MI=H, Li, Na, K, Rb, Cs) and their crystalline hydrates

Problems concerning the structures of compounds of the series M^IP(As)UO⁶.nH ₂O (M^I = H, Li, Na, K, Rb, Cs; n = 4 for M^I = H, Li and n = 3 for M^I = Na, K, Rb, Cs) are examined. The results of X-ray powder diffraction, thermographic, and IR spectroscopic studies on the above compounds are analysed. The experimental standard enthalpies of formation (Δ_fH^o) of the compounds M^I P(As)UO₆ and their crystalline hydrates are discussed. The characteristic features of the variation of Δ_fH^o as a function of the structural characteristics of the compounds and of the physical properties of the Group I elements in the series of phosphorus and arsenic compounds are described. The enthalpies of dehydration and ion exchange involving the compounds investigated are presented. The bibliography includes 103 references.