The heat capacity of crystalline I-amino adamantane over the temperature range from (5 to 370) K, the temperatures and the enthalpies of its solid-to-solid phase transitions, T-trs,T-1 = (241.4 +/- 0.2) K and Delta H-trs,1(m)degrees = (1716 +/- 10) J . mol(-1); T-trs,T-2 = (284.6 +/- 0.1) K and Delta H-trs,2(m)degrees = (5309 +/-5) J . mol(-1), were obtained by the adiabatic calorimetry. The thermodynamic functions of the compound in the crystalline state were derived. The saturated vapour pressure and the sublimation enthalpy {Delta H-sub(m)degrees(298.15 K) = (61.65 +/- 0.63) kJ . mol(-1)} were determined from the results of the measurements by the effusion Knudsen method and by the transpiration method. The enthalpy of combustion and the enthalpy of formation for crystalline 1-aminoadamantane were measured in a static-bomb isoperibol combustion calorimeter: Delta H-c(m)degrees (cr,298.15 K) = (-6169.2 +/- 1.9) kJ.mol(-1) and Delta H-f(m)degrees(cr,298.15 K) = (-195.4 +/- 2.3) kJ . mol(-1). The thermodynamic properties in the ideal gaseous state were calculated by the statistical thermodynamics method. The molecular and spectral data for 1-aminoadamantane were obtained from quantum-chemical calculations (B3LYP/6-31+G*) and from Raman and i.r. spectroscopic studies. (c) 2007 Elsevier Ltd. All rights reserved.