The total vapour pressure of {xXe + (1-x)C2H4O}(1) has been measured at T = 182.33 K (the triple point of nitrous oxide). The system exhibits liquid-liquid immiscibility at this temperature. The excess molar Gibbs energy (G(m)(E)) has been calculated, as a function of composition, from the vapour pressure data. The results were interpreted using the Deiters equation of state.