Heat capacities and volumes of NaCl, MgCl 2 , CaCl 2 , and NiCl 2 up to 6 molal in water

Abstract

It has been claimed by Enderby and co-workers that changes in long-range order occur in NiCl 2 aqueous solutions at high concentrations. To investigate the possibility of a transition, the partial molar heat capacities and volumes of NiCl 2 , CaCl 2 , MgCl 2 , and NaCl were measured and compared in water at 25 °C up to 6 mol kg −1 . In the case of NaCl, data were also measured at 5 and 45 °C. A slight change in slope of [Formula: see text] is observed for NiCl 2 around 4 mol kg −1 which may suggest a third or higher order transition. However, the change is too small to support unambiguously any particular model for the high concentration region.