and ?₂ are the surface energies of the two new surfaces, and ?₁₂ is the interfacial energy.

This methodology can also be used to discuss cleavage that happens in another medium: ?₁₂ = (1/2)W₁₂₁ = (1/2)W₂₁₂. These two energy quantities refer to the energy that is needed to cleave one species into two pieces while it is contained in a medium of the other species. Likewise for a three species system: ?₁₃ + ?₂₃ - ?₁₂ =