where Δ Δ H A B m i x is the binary enthalpy of mixing for A and B. Zhang et al. found, empirically, that in order to form a complete solid solution, ΔH mix should be between -10 and 5 kJ/mol. In addition, Otto et al. found that if the alloy contains any pair of elements that tend to form ordered compounds in their binary system, a multi-component alloy containing them is also likely to form ordered compounds.