Energetics of ternary nitride formation in the (Li,Ca) - (B,Al) - N system

High-temperature oxide melt drop solution calorimetry was used to study the energetics of nitride formation. The standard enthalpies of formation of several binary and ternary nitrides were determined. These values (in kJ mol^-1) are as follows: ΔH_f^o (AlN) = -311.1 ± 4.3, ΔH_f^o (Li₃BN₂) = -534.5 ± 16.7, ΔH_f^o (Li₃AlN₂) = -567.8 ± 12.4, and ΔH_f^o (Ca₃B₂N₄) = -1062.1 ± 15.4. From these values and others available in the literature, the enthalpies of formation of the ternary nitrides from the binary nitrides were calculated. The energetics of ternary nitride formation appear to be dominated by differences in the acid/base character of the cations.