General thermodynamic equations for the surface tension of liquids and solids

The old-but-new Frumkin derivation of the first and second Gokhshtein equations follows from one thermodynamic relationship general to the surface tension of both solid and liquid electrodes: ∂ γ / ∂ E = - ∂ Q / ∂ A assical Lippman equation is also derived from this general relationship as a particular case of the second Gokhshtein equation. We have considered the hierarchy of these equations and discussed the straightforward application of the classical Lippmann equation for solids, accounting for the elasticity of the surface structured layers of liquids.