Equilibrium vacancy parameters and limit temperature of nonequilibrium melting in osmium

For osmium, based on experimental data on enthalpy and the averaged heat capacity obtained by the method of mixing within the temperature range of $1150$–$2960$ K, for the first time the parameters of the equilibrium vacancies for this metal have been determined: the vacancy formation energy $E = 1.8$ eV, the vacancy concentration at melting $c = 3.3\%$, and the vacancy formation entropy $S = 25.6$ J/(mol K). The limit temperature of the onset of nonequilibrium melting of osmium $T_{\mathrm{m}} = 4256$ K and its relative value $T_{\mathrm{lim}}/T_{\mathrm{m}} = 1.30$ has been calculated.