New estimate of osmium melting heat

The value of the osmium melting heat $\Delta H_m = 57.85$ kJ/mol, presented in reference handbooks was obtained about $35$ years ago from a wide extrapolation (in temperature) of experimental data on the melting entropy of the FCC and the HCP elements of the Periodic Table. Using the correlation of data on the surface tension (developed by B. D. Summ), the melting heat, and the surface layer structure for osmium, the authors obtain a new estimate, $\Delta H_m = 30$–$40$ kJ/mol, which is half of the reference value.