Chemical stability of alkali elements' uranyl vanadates in aqueous solutions

The chemical stability of uranyl vanadates A(I)VUO(6)center dot nH(2)O (A(I)-Li, Na (n = 2), K, Rb, Cs (n = 0)) in aqueous solutions was investigated for the first time. The medium acidity was established to have the largest influence on the state of the studied compounds in heterogeneous aqueous-salt systems. The compounds were found to be stable in the pH range of 0 - 2-11 - 14. Alkaline elements uranyl vanadates' solubility changes from 10(-8) to 10(-6) mol/l in neutral solutions to 10(-4) to 10(-1) mol/l in acidic and basic media. The chemical stability of A(I)VUO(6).nH(2)O increases from lithium to caesium. The solubility products were calculated to be in the range of 10(-29.2) (Li) to 10(-34.1) (Cs). Gibbs free energies of the formation and dissolution of the studied compounds, their solubility curves and the speciation diagrams for U (VI) and V (V) in both liquid and solid phases were also calculated.

Automated summary

The chemical stability of uranyl vanadates A(I)VUO(6)center dot nH(2)O (A(I)-Li, Na (n = 2), K, Rb, Cs (n = 0)) in aqueous solutions was studied for the first time. It was found that the medium acidity had the largest influence on the compounds' state in heterogeneous aqueous-salt systems. The compounds were stable in the pH range of 0 - 2-11 - 14. Alkaline elements uranyl vanadates' solubility changes depending on the solution's acidity, with solubility increasing in acidic and basic media.