On a new phase coexistence above the consolute point of Na-NH₃ solution

EMF measurements have been performed on Na-NH₃ solution above its well established liquid-liquid critical point. The existence of a new phase transition reported earlier by Steinberg et al. (1980) is confirmed and its coordinates are traced throughout the interval of concentration from 4.8 to 8.5 mol% Na and for temperatures from 238 to 285K. The difference in partial molar entropy of the phases has been estimated to be of the order of the gas constant.