Heat capacity for 1-butyl-3-methylimidazolium nitrate [C-4 mim][NO3] in the temperature range (5-370) K has been measured by adiabatic calorimetry. Temperatures and enthalpies of its phase transitions have been determined. Thermodynamic functions have been calculated for the crystalline and the liquid states. Phase transition temperatures for set of nitrate salts have been compared. Enthalpy of combustion and enthalpy of formation for crystalline [C-4 mim][NO3] have been determined using a static-bomb isoperibol combustion calorimeter. A correlation scheme for the estimation of C-p of ionic liquids has been developed. (c) 2008 Elsevier B.V. All rights reserved.