It is pointed out that the experimentally-measured quantity usually termed "surface free energy" is in fact a part of the free enthalpy which is due to the presence of the surface (referred to unit surface). This quantity, denoted by γio for the polycrystalline solid chemical element i, is connected to the internal free enthalpy of atomization ΔGa,i* by the relation γioio=αioΔGa,i* where io is the molar surface area, and αio is a constant. Its physical meaning is given to a relatively good approximation. Approximate methods of calculation based on experimental data give values of αio at any temperature for metallic, semimetallic and covalently-bonded solid chemical elements. Using these procedures, the values of γio at 298.2 K and at the melting temperature are tabulated.