The standard molar enthalpies of formation, in the crystalline phase, of three halogenated 1-phenylpyrrole derivatives, namely 1-(4-fluorophenyl)pyrrole, 1-(4-chlorophenyl)pyrrole, and 1-(4-iodophenyl)pyrrole were derived from the respective enthalpies of combustion, measured by rotating-bomb combustion calorimetry. Their enthalpies of sublimation, at T = 298.15 K. were obtained from the Knudsen mass-loss effusion technique. From these two experimental parameters, the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of 1-(4-fluorophenyl)pyrrole, 1-(4-chlorophenyl)pyrrole, and 1-(4-iodophenyl)pyrrole were calculated, respectively, as (26.2 +/- 2.4) kJ . mol(-1), (196.2 +/- 2.5) kJ . mol(-1), and (311.5 +/- 2.4) kJ . mol(-1). The gas-phase enthalpies of formation of both fluorine and chlorine compounds were estimated by G3(MP2)//B3LYP computations. For the iodine compound, the B3LYP/6-311G(d):ECP46MDF approach was employed. Additionally, the DFT calculations were extended to estimate the enthalpy of formation of the bromine derivative, 1-(4-bromophenyl)pyrrole, performed at the B3LYP/6-311G(d) level of theory. (C) 2010 Elsevier Ltd. All rights reserved.