Effect of hydration degree on proton conductivity of disubstituted uranyl orthophosphate

The effect of the hydration degree of disubstituted uranyl orthophosphate on the value and the character of conductivity of UO2HPO4x4H2O(1) and UO2HPO4xH2O(2) polycrystal samples is investigated. Temperature dependence of the 1st sample conductivity is complex; the curve of conductance obtained at cooling does not coincide with the dependence obtained at heating forming the hysteresis loop in the region of 315-328 K. The value of the 1st conductivity at 300 K is (1.2-1.8)x10-3 Ohmxcm-1. The cooling and heating curves for the 2nd sample coincide, the value of conductivity at 300 K is (6-8)x10-7 Ohmxcm-1. Data on the 1st conductivity correspond to representation, according to which the aqueous lattice of the 1st sample is represented. It is supposed that the main mechanism of proton conductivity of the 2nd sample is the exchange of protons between the neighbouring P-OH groups with possible participation of a water molecule