The energy of combustion of crystalline 1,2,3,4-tetrachlorodibenzo-p-dioxine (-5122.9 ± 7.4 kJ/mol) was measured using an isothermic-shell calorimeter with a rotating platinum plated bomb. The result was used to calculate the enthalpy of combustion (-5120.4 ± 7.4 kJ/mol) and formation (−267.8 ± 7.6 kJ/mol) for the crystalline state. The enthalpy of sublimation was measured using a Calvet microcalorimeter at 411.5 K (116.0 ± 2.6 kJ/mol); recalculation to T = 298.15 K gave 118.7 ± 2.6 kJ/mol. The enthalpy of formation of 1,2,3,4-tetrachlorodibenzo-p-dioxine in the gas state was calculated (−149.1 ± 8.0 kJ/mol)

The standard energies of combustion of four cyclooctane substituted triangulanes and one compound related to them were measured in a water isothermic-shell calorimeter with a stationary self-sealing bomb for the first time. The standard enthalpies of vaporization were experimentally determined for two compounds and estimated for the others. The standard enthalpies of formation of these substances in the liquid and CFaseous states were calculated. The experimental data were used to analyze the possibility of estimating the enthalpies of formation of polycyclic hydrocarbons of the class under consideration by additive methods.

The energies of combustion and standard enthalpies of formation of nitrocyclopropane and nitrospiropentane were experimentally determined for the first time, and their enthalpies of vaporization were estimated.

The standard molar enthalpy of combustion of 2-chlorodibenzo-p-dioxin was redetermined using the sample of high purity by rotating-bomb calorimetry: ΔcH0m(cr)=−(5558.2±3.5) kJ·mol−1. The values of standard molar enthalpies of formation were derived for crystalline and gaseous states: ΔfH0m(cr)=−(187.9±3.8) kJ·mol−1 and ΔfH0m(g)=−(90.7±3.8)kJ·mol−1.

The standard molar energy of combustion of fullerene C70 was measured at T=298.15K by means of a static bomb isoperibolic macrocalorimeter, ΔcU0m(cr)=−(29998±32)kJ·mol−1. The standard molar enthalpies of formation of fullerene C70 in the crystalline and gaseous states were calculated from the experimental data, ΔfH0m(cr)=(2452±33)kJ·mol−1 and ΔfH0m(g)=(2652±34)kJ·mol−1. The average CO2 fraction in the combustion products was equal to (0.9995±0.04) of theoretical.

The standard molar enthalpy of combustion of hydrofullerene C60H36 was determined by static bomb calorimetry, Delta(c)H(m)(o) = -(29769 +/- 25) kJ.mol(-1). Using this result and the standard molar enthalpy of sublimation, Delta(sub)H(m)(o) = (175 +/- 5) kJ.mol(-1), the values of the standard molar enthalpies of formation of C60H36 in the crystalline and gaseous states were calculated: Delta(f)H(m)(o)(C60H36, cr) = (1013 +/- 26) kJ.mol(-1) and Delta(f)H(m)(o)(C50H36, g) = (1188 +/- 26) kJ.mol(-1). The enthalpy of reaction C60H36(g) = C-60(g) + 36 H(g) was found to be (9196 +/- 30) kJ.mol(-1), or (255.4 +/- 0.8) kJ.mol(-1) per one C-H bond. The enthalpy of reaction C60F36(g) + 36 H(g) = C60H36(g) + 36 F(g) was calculated, Delta(r)H(m)(o) = (1421 +/- 203) kJ.mol(-1), or (139.5 +/- 5.6) kJ.mol(-1) per one H atom. The enthalpies of bond breaking and of F to H replacement were compared with the analogous values in some other organic compounds.

The standard molar enthalpy of combustion of dibenzo- p -dioxin (DD) was measured at T= 298.15 K by static-bomb combustion calorimetry: ΔcHmo(cr) =−(5723.8 ± 1.4)kJ · mol−1. The standard molar enthalpy of sublimation of this compound was measured by microcalorimetry: ΔcrgHmo= (91.45 ± 0.76)kJ · mol−1. These values were used to derive the standard molar enthalpies of formation of DD in the crystalline and gaseous states: ΔfHmo(cr) =−(141.6 ± 2.1)kJ · mol−1and ΔfHmo(g) =−(50.1 ± 2.2)kJ · mol−1. The specially obtained sample of DD of high purity {mole fraction x= (0.9999 ± 0.0001)} was used in all measurements.

The recently measured heat of formation ΔH f o of C60F36(g) is submitted for extensive computational treatment. The computations are performed at the AM1, PM3 and SAM1 semiempirical quantum-chemical levels on a set of selected isomers, especially those of T, C3, and D3d symmetries. The SAM1 method produces somewhat lower values than PM3 and, in particular, AM1 (as is the case for pristine fullerenes). For example, the SAM1 computed value for the T isomer is −1293 kcal/mol; i.e., it is within the experimental error. However, the issue of isomerism should also be taken into consideration accordingly and related kinetic aspects should be checked using computations. Even without these two additional steps being carried out, the agreement between the observed and computed values is encouraging.

The standard molar enthalpy of combustion of fluorofullerene C60F36 was determined by rotating-bomb calorimetry, Delta(c)H(m)(o) = -24692 +/- 199 kJ.mol(-1). Using this result and the standard molar enthalpy of sublimation, Delta(sub)H(m)(o) = 139 +/- 8 kJ.mol(-1), the values of the standard molar enthalpies of formation of C60F36 in the crystalline and gaseous states were found to be -5362 +/- 201 kJ.mol(-1) and -5223 +/- 201 kJ.mol(-1), respectively. The enthalpy of reaction C60F36(g) = C-60(g) + 36F(g) was calculated, Delta(r)H(m)(o)(298.15 K) = (10617 +/- 202) kJ.mol(-1), or 294.9 +/- 5.6 kJ.mol(-1) per one C-F bond. The comparison with the enthalpy of reaction C60F48 = C-60(g) + 48F(g), Delta(r)H(m)(o)(298.15 K) = 287.5 +/- 3.5 kJ.mol(-1) per C-F bond leads to a preliminary conclusion that C-F bond enthalpy decreases with amount of F atoms attached to the fullerene cage.

The standard massic energies of combustion of three alkyl-derivative of adamantane were measured atT= 298.15 K by static-bomb combustion calorimetry. The standard molar enthalpies of formation in the liquid and gaseous states were obtained from these data. The enthalpies of some reactions of isomerization were calculated from the equilibrium study and compared with the results of calorimetric measurements.

The enthalpies of formation of dibenzo-p-dioxin and its polychlorinated derivatives have been measured, and a complete set of the enthalpies of formation has been constructed.

The standard molar enthalpy of combustion of fluorinated fullereneC60F48 was determined by rotating-bomb calorimetry,ΔcHmo=−(24638 ± 163)kJ · mol−1. Using this result and the standard molar enthalpy of sublimation,ΔsubHmo= (109 ± 7)kJ · mol−1, the values of the standard molar enthalpies of formation of C60F48in the crystalline and gaseous states were found to be −(7563 ± 166)kJ · mol−1and −(7454 ± 166)kJ · mol−1, respectively. The enthalpy of reaction C60F48(g) = C60(g) + 48F(g) was calculated,ΔrHmo (298.15 K) = (13800 ± 167)kJ · mol−1, orΔrHmo (298.15K )/48 = (287.5 ± 3.5)kJ · mol−1.

The standard massic energies of combustion of eight polycyclic compounds were measured atT=298.15K by static-bomb combustion calorimetry. The standard enthalpies of vaporization and sublimation were measured in a Calvet microcalorimeter, or adiabatic vaporization calorimeter, or derived from ebulliometric measurements of the vapour pressure as a function of temperature. The standard molar enthalpies of formation in the condensed and gaseous states were obtained from these data. The peculiarities in the strain energies of polycyclic compounds are discussed.

The standard molar enthalpy of combustion of crystalline 2,3-dichlorodibenzo-p-dioxin was determined by rotating-bomb calorimetry: ΔcHm°=−(5406.4±6.6) kJ·mol−1. Using this result and the standard molar enthalpy of sublimation, ΔsubHm°=(108.6±1.0) kJ·mol−1, the values of the standard molar enthalpies of formation of 2,3-dichlorodibenzo-p-dioxin in the crystalline and gaseous states were found to be −(220.5±6.8) kJ·mol−1and −(111.9±6.9) kJ·mol−1, respectively. The standard molar enthalpy of formation of gaseous 2,3,7,8-tetrachlorodibenzo-p-dioxin was estimated: ΔfHm°(g)≈−164.6 kJ·mol−1.