The heat capacity of (n-C12H25NH3)2ZnCl4 was measured at 280-500 K by means of an automatic adiabatic calorimeter. Two phase transitions, one solid-solid and the other solid-liq., were found at 364.3 ?0.1 and 435.1 ?0.1 K resp. The enthalpies and entropies of these transitions are 66.79 ?0.35 kJ/mol and 183.3 ?11.0 J/K mol for the solid-solid transitions, and 9.12 ?0.14 kJ/mol and 20.96 ?0.32 J/K.mol for the solid-liq. transition, resp. The selected thermodn. properties are tabulated in 10 K interval from 280 to 500 K.

Key words: AMMONIUM COMPOUND, THERMODYNAMIC PROPERTIES, PHASE TRANSFORMATION, ENTROPY, ENTHALPY, CALORIMETRY, SPECIFIC HEAT, C12 COMPOUNDS, ZINC CHLORIDE, THERMAL INSULATION