Application of rotate-bomb calorimeter for determining the standard molar enthalpy of formation of Ln(Pdc)3(Phen)

Abstract

Thirteen solid ternary complexes Ln(Pdc)3(Phen) (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu;) have been synthesized in absolute ethanol by rare-earth element chloride low hydrate reacting with the mixed ligands of ammonium pyrrolidinedithiocarbamate (APdc) and 1,10-phenanthroline · H2O (o-Phen · H2O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes showed that the Ln3+ ion was coordinated with six sulfur atoms of three Pdc− and two nitrogen atoms of o-Phen · H2O. It was assumed that the coordination number of Ln3+ is eight. The constant-volume combustion energies of the complexes, ΔcU, were determined by a precise rotate-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, ΔcHmo, and standard molar enthalpies of formation, ΔfHmo were calculated.