Thermodynamics of lanthanide elements. Part 1. Enthalpies of formation of some lanthanide tribromides

Abstract

Enthalpies of solution have been measured for lanthanide tribromides (MBr₃; M = La, Pr, Nd, Sm, Gd, Dy, or Er) in 1.0, 10^–1, and 10^–3 mol dm^–3 hydrochloric acid. Combination of the resulting values with auxiliary thermodynamic data yields the following standard enthalpies of formation (in kJ mol^–1)at 298.15 ± 0.05 K: LaBr₃(s), –907.2 ± 1.7; PrBr₃(s), –891.4 ± 1.7; NdBr₃(s), –873.2 ± 1.7; SmBr₃(s), –857.3 ± 2.0; GdBr₃(s), –828.8 ± 2.4; DyBr₃(s), –834.1 ± 2.8; and ErBr₃(s), –835.8 ± 10.