Some properties of the compound energy model

The compound energy model is a modification of the bond energy model. It is based on the use of model parameters defined as Δ0UAB = 0UAB − a′0UAA − a″0UBB, where a′ and a″ are stoichiometric coefficients in a compound Aa′Ba″ and may be different. The bond energy model was originally defined for a′ = a″ = 1/2 and uses a model parameter vAB = EAB − EAA/2 − EBB/2. Recently, Oates and Wenzl also extended the bond energy model to the case a′ ≠ a″ but only under the condition that there are no bonds inside a sublattice. It is now shown that their treatment is identical to the compound energy model in the case of two sublattices. It appears as a semantic question whether or not the method of solving the problem appearing when a′ ≠ a″ justifies the new name “Compound Energy Model” or not.