Determination of standard molar enthalpy of formation for crystalline endo-tricyclo[5.2.1.0(2,6)]decane by an isoperibol oxygen-bomb combustion calorimeter

The construction and principle of the new-established isoperibol oxygen-bomb combustion calorimeter are described. The energy equivalent (epsilon(calor)) of the calorimeter has been determined from ten combustion experiments using about 0.7 g of NIST 39i benzoic acid with a certified mass energy of combustion, Delta(c)U = -(26434 +/- 3) J g(-1), under experimental conditions: epsilon(calor) = (13572 +/- 2) J K-1. The constant-volume energy of combustion of the compound, endo-tricyclo[5.2.1.0(2,6)]decane (C10H16), has been determined to be Delta U-c (C10H16, s) = -(6070 +/- 3) kJ mol(-1) by means of the oxygen-bomb combustion calorimeter at T = (298.15 +/- 0.001) K. The standard molar enthalpy of combustion of the sample has been calculated, Delta(c)H(m)(degrees)(C10H16, s) = -(6060 +/- 3) kJ mol(-1), from the constant-volume combustion energy. From the Hess thermochemical cycle, the standard molar enthalpy of formation of the compound has been determined, Delta(f)H(m)(degrees)(C10H16, s) = -(161.83 +/- 3.55) U mol(-1).