Thermochemistry of the NaBr-Nal Solid Solution at 750 K – A Knudsen Effusion Mass Spectrometric Study

The excess molar Gibbs energy and partial pressures at a temperature of 750 K for the solid phase of the NaBr-NaI system were determined by Knudsen effusion mass spectrometry. The parameters of the Redlich-Kister equation for G^E_m resulted in kJ mol⁻¹ as B₁ = 6.46 and B₂ = −1.12. The thermodynamic data obtained from the molecular ion intensities of NaBr⁺ and NaI⁺ and those obtained from the fragment ion intensities of Na₂Br⁺ (from Na₂Br₂) and Na₂I⁺ (from Na₂I₂) agree well. The results of this work are discussed with respect to those reported by other authors.