Thermodynamics of copper sulfides IV. Heat capacity and thermodynamic properties of Cu1.90S from 5 K to 750 K, Cu1.95S from 5 K to 1000 K, Cu1.98S from 300 K to 1000 K, and Cu1.995S from 300 K to 750 K

The heat capacities of Cu1.90S, Cu1.95S, Cu1.98S, and Cu1.995S have been measured by adiabatic-shield calorimetry. All samples have been characterized by powder X-ray diffraction in the temperature interval studied. A revised version of the copper-rich part of the phase diagram is presented. All transitions are characterized by hysteresis in the attainment of equilibrium and a greater or lesser dependence on thermal history and/or thermal recycling. Thermodynamic functions have been evaluated and selected values are, for R = 8.3144 J[middle dot]K-1[middle dot]mol-1:Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28934/1/0000771.pd