Crystal structure of 1-dodecylamine hydrochloride (C12H28NCl)(s) has been determined by an X-ray crystallography. Lattice potential energy and the molar volumes of the solid compound and its cation were respectively obtained. The enthalpy of dissolution of the compound was measured by an isoperibol solution-reaction calorimeter at 298.15 K. The molar enthalpy of dissolution at infinite dilution was determined to be Delta H-s(m)theta = 30.36 kJ mol(-1), and relative apparent molar enthalpies (Phi(L)) relative partial molar enthalpies (L-2) Of the compound and relative partial molar enthalpies (L-1) of the solvent (double distilled water) at different concentrations in (mol kg(-1)) were obtained through fitted multiple regression equation by means of Pitzer's theory. Finally, hydration enthalpies of the substance and its cation were calculated by designing a thermochemical cycle in accordance with lattice potential energy and the molar enthalpy of dissolution at infinite dilution (Delta H-s(m)theta). (C) 2009 Elsevier B.V. All rights reserved.