Thermodynamic Data of Formation

AHf is the enthalpy and AGf the Gibbs free energy in kcal/mol for the formation of gaseous OF2 from the gaseous elements. 

There is considerable uncertainty in the enthalpy of formation of OF2. It is not even clear whether the reaction is exothermic or endothermic. For discussions, see [1] and Fluor Erg.-Bd. 1, 1959, p. 225. 

A negative enthalpy, AH 298.16 = 4.06 2.2, results from measured enthalpies of the reaction of OF2 with H2 in a water-containing combustion bomb [10], for critical remarks, see 

Calculated values (selected) from the JANAF Tables [4]  

The enthalpy, entropy, and Gibbs free energy of formation of EuSe from the elements under standard conditions, AH298= -93.8 0.8 kcal/mol, AS298= -3.20 1.2 cal-mol -K and 298= -92.8 1.2 kcal/mol, were calculated from available literature data and the authors own thermodynamic data for EuSe, McMasters et al. [9]. The enthalpy of formation calculated from the atomization energy of Gordienko etal. [10] is 14 kcal/mol larger [9]. 

Selected values for AH° and AG° as a function of temperature up to 1600 K for the elements in their normal reference state (Eu is solid up to 1090 K and liquid from 1090 to 1700 K, Se is solid up to 494 K, liqui( 

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The atomization energy AHgt = 950.2 1.6 kJ/mol at 0 K was reported [1 ] (see also [13]) it is based on the measured enthalpy of formation, AfHgge=5.4 kJ/mol [14] (see the thermodynamic data of formation on p. 179). Atomization energies for about 65 molecules including PH3 were calculated with density functional models [15]. 

Earlier investigations of the physical properties of phosphane are described in Phosphor C, 1965, pp. 24/30 thermodynamic data of formation are given on pp. 10/1 and solubility data on p. 50 of that volume. 

Thermodynamic Data of Formation. The standard enthalpy of formation of gaseous PH3, fH298 = 5.4 1.7 kJ/mol, was calculated from the heats of the explosive decomposition of PH3/SbH3 mixtures with white phosphorus as the reference state and is the recommended value different experimental values are given in Phosphor C, 1965, pp. 10/1. The experimentally determined value yields AfG29s=13.4 and AfHo=13.39 kJ/mol [27]. Calculations from molecular constants with standard methods yielded thermodynamic data of formation and the equilibrium constant for the formation of PH3 as an ideal gas the reference states used were crystalline a white phosphorus (0 to 195 K), crystalline p white phosphorus (195 to 317 K), the melt (317 to 1180 K), and an ideal P2 gas at higher temperatures. Selected results are as follows [28] ... 

The standard thermodynamic data of formation and the ideal gas heat capacity correlations can be found in Appendix A. 

The standard thermodynamic data of formation of various hydrates were calculated from the Gibbs free energy of interaction AG with BaCl2 solution as follows ... 

The chemical properties of the binary rare-earth phosphides have been studied fully only for monophosphides, their thermodynamic characteristics have also been determined. Thermodynamic data of formation and atomization of the R monophosphides are listed in table 19. 

Thermodynamic Data of Formation. Heat Capacity. Thermodynamic Functions... 

The experimental enthalpies of formation are 296.6 2.1 kJ/mol for gaseous HN3 and 263.6 2.9 kJ/mol for the liquid at or slightly below ambient temperature and at constant pressure. The data were obtained from the heat of explosion [1]. Thermodynamic data of formation of gaseous and liquid HN3 and of a 1 M aqueous solution are summarized in Table 15. 

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