The standard molar heat capacity C-p,m(degrees) of adenine(cr) has been measured using adiabatic calorimetry over the range 6 < (T/K) < 310 and the results used to derive thermodynamic functions for adenine(cr) at smoothed temperatures. At T = 298.15 K C-p,m(degrees) = (142.67 +/- 0.29) J(.)K(-1.)mol(-1) and the third law entropy S-m(degrees) = (145.62 +/- 0.29) J(.)K(-1.)mol(-1). The standard molar Gibbs free energy of formation DeltarG(m)(degrees) at T = 298.15 K for crystalline adenine was calculated, using the standard molar enthalpy of formation for the compound and entropies of the elements from the literature, and found to be Delta(f)G(m)(degrees) = (301.4 +/- 1.0) kJ(.)mol(-1). The results were combined with solution calorimetry and solubility measurements from the literature to yield revised values for the standard molar thermodynamic properties of aqueous adenine at T = 298.15 K: Delta(f)G(m)(degrees) (313.4 +/- 1.0) kJ(.)mol(-1), Delta(f)H(m)(degrees) = (129.5 +/- 1.4) kJ(.)mol(-1), and S-m(degrees) = (217.68 +/- 0.44) J(.)K(-1) mol(-1). (C) 2003 Elsevier Ltd. All rights reserved.