A Detailed Study of the Dehydration Process in Synthetic Strelkinite, Na[(UO2)(VO4)] · nH2O (n = 0, 1, 2)

Abstract Synthetic strelkinite Na[(UO 2 )(VO 4 )] · n H 2 O ( n = 0, 1, 2) was systematically investigated by single crystal X-ray diffraction and thermoanalytical methods. The anhydrous form and two hydrates were isolated as single crystals and the structures of these phases solved: Na[(UO 2 )(VO 4 )], monoclinic, P2 1 / c , a = 6.0205(1) Å, b = 8.3365(1) Å, c = 10.4164(2) Å, β = 100.466(2)°, V = 514.10(1) Å 3 , R 1 = 0.0337; Na[(UO 2 )(VO 4 )] · H 2 O, monoclinic, P2 1 / c , a = 7.722(2) Å, b = 8.512(1) Å, c = 10.480(4) Å, β = 113.18(3)°, V = 633.3(3) Å 3 , R 1 = 0.1658; Na[(UO 2 )(VO 4 )] · 2 H 2 O, monoclinic, P2 1 / n , a = 16.2399(5) Å, b = 8.2844(2) Å, c = 10.5011(2) Å, β = 97.644(2)°, V = 1400.24(6) Å 3 , R 1 = 0.0776. A possible mechanism of the structural transformation processes during dehydration is proposed based on the structures of the anhydrous phase and the hydrates.