Such point defects were described using a model which was based upon the formula, (A,B,V)1(B,A,V)1, and the results were compared with the results of 2 models that were based upon combined defects by using the formulae: (A,B)1(B,A)1 and (A,V)1(B,A)1. The comparison was straightforward when close to the stoichiometric composition, but was not so when close to the pure elements. By using the more general model, it was demonstrated that the fact that vacancies were the predominant defect, in some B2 compounds with a small excess of B atoms, depended mainly on interactions between next-nearest neighbours rather than on a high enthalpy of formation of the compound.

Point Defects in B2 Compounds. M.Hillert, M.Selleby: Journal of Alloys and Compounds, 2001, 329[1-2], 208-13