Standard enthalpies of formation of uranium compounds VI. MUO 3 (M = Li, Na, K, and Rb)

Abstract

Enthalpies of solution of MUO3 (M = Li, Na, K, and Rb) in a (sulphuric acid + ceric sulphate) solution have been measured calorimetrically. In combination with the enthalpies of solution of U3O8(s), γ-UO3(s), and M2SO4(s) in this solvent the standard enthalpies of formation of MUO3 have been derived. The results obtained are: ΔHfo(s, 298.15 K)/kJ mol−1: LiUO3, − (1522.1 ± 1.7); NaUO3, − (1494.6 ± 1.6); KUO3, − (1522.9 ± 1.6); RbUO3, − (1520.9 ± 1.7).