The equilibrium vapour pressure of liquid {xN(2) + (1 -x)C2H6}(1) has been measured at T = 90.69 K. The excess molar Gibbs energies G(m)(E) have been calculated as a function of composition from the vapour pressure data. For the equimolar mixture G(m)(E) (X = 0.5) (985 +/- 14) J (.) mol(-1). Excess molar enthalpies H-m(E) have also been measured at T (92.1 +/-0.1) K and p = (0.79 +/- 0.12) MPa using a low-temperature computer-interfaced high-pressure flow calorimeter. For the equimolar mixture HE (x = 0.5) = 426.9 J (.) mol(-1). The results show that the system is only partially miscible at both temperatures. The limits of (liquid + liquid) immiscibility have been determined as 0.123 +/- 0.010 < x < 0.958 +/- 0.004. The results have been interpreted using the Deiters equation of state.