Total pressures of binary solutions of [bmim]Zn2Cl5 (1)/NH3 (2) at ammonia mole fractions of x(2) = (0.83-0.94) for T=(323.15-563.15) K at interval of 20 K were measured by a static method. The experimental data were correlated by a modified UNIFAC model involving four groups and the new binary interaction parameters were obtained. The measurement uncertainties and the maximum deviation of the correlation are lower than 4.3% and 5%, respectively. It is found that the addition of metal ion-containing ionic liquid [bmim]Zn2Cl5 can sharply reduce the ammonia pressure. The ammonia partial pressures of [bmim]Zn2Cl5/NH3 solutions were compared with that of ZnCl2 center dot 6NH(3) and four binary solutions containing different ionic liquids. It is indicated that the solubilities of ammonia in [bmim]Zn2Cl5 is higher than that in other ionic liquids but lower than that in ZnCl2. This work suggests that [bmim]Zn2Cl5/NH3 may be useful in absorption refrigerators and heat pumps. (C) 2013 Elsevier B.V. All rights reserved.