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Taking into account the large volume of new data, the calculation of the melting curve of osmium, together with determination of its heat of fusion, has been revised. The new results agree noticeably better with quantum mechanical calculation data. It is significant that the slope parameter for the melting curve is compatible with the new estimate of the heat of fusion, which was approximately half the value accepted in the reference literature. It is shown that a detailed analysis of periodic table confirms the choice of entropy and heat of fusion. [ABSTRACT FROM AUTHOR]

The value of the osmium melting heat, ΔHm= 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, ΔHm = 30−40 kJ/mol, which is half of the reference value. [ABSTRACT FROM AUTHOR]