A thermodynamic investigation of the nickel(II) chloride-acetonitrile system

Abstract

Equilibrium vapor pressures were determined at temperatures between 294 K and 353 K for the NiCl 2-CH 3CN system. Compositions studied ranged from molar ratios of CH 3CN to NiCl 2 of 0.27 to 1.90. Three stoichiometric compounds were identified: NiCl 2(CH 3CN) 2, NiCl 2(CH 3CN), NiCl 2(CH 3CN)0.88. Per mole of gaseous CH 3CN the values of Δ H o and Δ S o were calculated to be 52.0 ±0.4 kJ mol −1 and 149.0±1.3 J mol −1 K −1 for the decomposition of NiCl 2(CH 3CN) 2, and 25.9 ±0.8 kJ mol −1 and 58.6± 2.1 J mol −1 K −1 for the decomposition of NiCl 2(CH 3CN). Below a composition of NiCl 2(CH 3CN) 0.88 the phase diagram is complex and could not be interpreted in terms of specific stoichiometric compounds.