Sulfur thermodynamic properties

Table 5. Physical and Thermodynamic Properties of Sulfur Monochloride, S2CI2...

Physical Properties. Sulfuryl chloride [7791-25-5] SO2CI2, is a colorless to light yellow Hquid with a pungent odor. Physical and thermodynamic properties are Hsted ia Table 7. Sulfuryl chloride dissolves sulfur dioxide, bromine, iodine, and ferric chloride. Various quaternary alkyl ammonium salts dissolve ia sulfuryl chloride to produce highly conductive solutions. Sulfuryl chloride is miscible with acetic acid and ether but not with hexane (193,194). 

Physical Properties. Sulfur dioxide [7446-09-5] SO2, is a colorless gas with a characteristic pungent, choking odor. Its physical and thermodynamic properties ate Hsted in Table 8. Heat capacity, vapor pressure, heat of vaporization, density, surface tension, viscosity, thermal conductivity, heat of formation, and free energy of formation as functions of temperature ate available (213), as is a detailed discussion of the sulfur dioxide—water system (215). 

A study on the thermodynamic properties of the three SO phases is given in Reference 30. Table 1 presents a summary of the thermodynamic properties of pure sulfur trioxide. A signiftcandy lower value has been reported for the heat of fusion of y-SO, 24.05 kj /kg (5.75 kcal/kg) (41) than that in Table 1, as have slightly different critical temperature, pressure, and density values (32). 

The thermodynamic properties of sulfur trioxide, and of the oxidation reaction of sulfur dioxide are summarized in Tables 3 and 4, respectively. Thermodynamic data from Reference 49 are beheved to be more accurate than those of Reference 48 at temperatures below about 435°C. 

TABLE 2-347 Thermodynamic Properties of Saturated Sulfur Hexafluoride (SF ) ... 

PS Brereton, FJM Verhagen, ZH Zhou, MWW Adams. Effect of iron-sulfur cluster environment m modulating the thermodynamic properties and biological function of ferredoxm from Pyrococcus furiosus. Biochemistry 37 7351-7362, 1998. 

THERMOSIM Module 1 EQUIL Gulf Publishing Company, Book Division Melissa Beck P.O. Bo 2608 Houston, TX 77252 (713) 520-4444 Database of thermodynamic properties of 200 hydrocarbons, 9 non-bydrocaibon gases, carbon, and sulfur. Requires 512K memory and 2 disk drives. 

Values taken from S. Glasstone. Thermodynamics for Chemists. D. Van Nostrand Company Inc., Toronto, p. 443 (1947). The values tabulated in this reference were taken from D. N. Craig and G. W. Vinal, J. Res. Natl. Bur. Stand.. Thermodynamic Properties of Sulfuric Acid Solutions and Their Relation to the Electromotive Force and Heat of Reaction of the Lead Storage Battery", 24, 475-490 (1940). More recent values at the higher molality can be found in W. F. Giauque. E. W. Hornung. J. E. Kunzler and T. R. Rubin, The Thermodynamic Properties of Aqueous Sulfuric Acid Solutions and Hydrates from 15 to 300° K", J. Am. Chem. Soc.. 82, 62-70 (1960). 

The thermodynamic properties of sulfur clusters have been investigated by Steudel et al. [60] who examined the reaction enthalpies of the interconversion reactions... 

For the cytochrome c-plastocyanin complex, the kinetic effects of cross-linking are much more drastic while the rate of the intracomplex transfer is equal to 1000 s in the noncovalent complex where the iron-to-copper distance is expected to be about 18 A, it is estimated to be lower than 0.2 s in the corresponding covalent complex [155]. This result is all the more remarkable in that the spectroscopic and thermodynamic properties of the two redox centers appear weakly affected by the cross-linking process, and suggests that an essential segment of the electron transfer path has been lost in the covalent complex. Another system in which such conformational effects could be studied is the physiological complex between tetraheme cytochrome and ferredoxin I from Desulfovibrio desulfuricans Norway the spectral and redox properties of the hemes and of the iron-sulfur cluster are found essentially identical in the covalent and noncovalent complexes and an intracomplex transfer, whose rate has not yet been measured, takes place in the covalent species [156]. 

Tudge AP, Thode HG (1950) Thermodynamic properties of isotopic compounds of sulfur. Can J Res B28 567-578... 

Thermodynamic properties for explosion calculations are presented for major organic chemical compounds. The thermodynamic properties include enthalpy of formation, Gibbs free energy of formation, internal energy of formation and Helmholtz free energy of formation. The major chemicals include hydrocarbon, oxygen, nitrogen, sulfur, fluorine, chlorine, bromine, iodine and other compound types. 

Ueda A, Sakai S (1984) Sulfur isotope study of Quaternary volcanic rocks from the Japanese Island Arc. Geochim Cosmochim Acta 48 1837-1848 Urey HC (1947) The thermodynamic properties of isotopic substances. J Chem Soc 1947 562 Urey HC, Brickwedde FG, Murphy GM (1932) A hydrogen isotope of mass 2 and its concentration. Phys Rev 40 1... 

The normal vibrations and structural parameters of Sg S, S, and Sjj have been used to calculate several thermodynamic functions of these molecules in the gaseous state. Both the entropy (S°) and the heat capacity (C°) are linear functions of the number of atoms in the ring in this way the corresponding values for Sj, Sg, Sjo and can be estimated by inter- and extrapolation For a recent review of the thermodynamic properties of elemental sulfur see Ref. 

The results described above show that despite several decades of extensive research activities the field of homocyclic sulfur molecules is still full of open questions. Basic knowledge concerning the thermodynamic properties of most molecules is lacking, and even the homolytic dissociation energy of the Sg ring molecule is unknown. 

It is convenient to use phase diagrams [46] to represent the thermodynamic properties that determine the stability and equilibrium composition of water-containing aerosols. The properties of interest are the temperature, the vapour pressure and composition of the various components in the condensed phases. This is particularly important with respect to the composition and stability of the various hydrates formed at low temperature in the nitric acid-water [47] and sulfuric acid-water binary systems [48], and the ternary systems HjSO/HNOj/HjO and HjSO/HCl/HjO [49],... 

We now see that mitochondria contain a variety of molecules—cytochromes, flavins, ubiquinone, and iron-sulfur proteins—all of which can act as electron carriers. To discuss how these carriers cooperate to transport electrons from reduced substrates to 02, it is useful to have a measure of each molecule s tendency to release or accept electrons. The standard redox potential, E°, provides such a measure. Redox potentials are thermodynamic properties that depend on the differences in free energy between the oxidized and reduced forms of a molecule. Like the electric potentials that govern electron flow from one pole of a battery to another, E° values are specified in volts. Because electron-transfer reactions frequently involve protons also, an additional symbol is used to indicate that an E° value applies to a particular pH thus, E° refers to an E° at pH 7. 

Interestingly, there have been repeated attempts to view such gradual structural changes due to chemical equilibria as phase transitions as well [262]. Instructive examples for such an analysis are living polymers — for example, in demixing solutions of polymers [263] and in sulfur [264], where the reversible polymerization process has been treated as a second-order phase transition. The experimental evidence for such an interpretation is, however, at best weak [265], and classical association models [266] describe the thermodynamic properties equally well. 

E. S. Domalski and E. D. Hearing,/. Phys. Chem. Ref. Data, 22, 805 (1993). Estimation of the Thermodynamic Properties of Carbon-Hydrogen-Nitrogen-Oxygen-Sulfur-Halogen Compounds at 298.15 K. 

Clegg SL, Brimblecombe P (1995) Application of a multicomponent thermodynamic model to activities and thermal properties of 0 40 mol kg 1 aqueous sulfuric acid from < 200 to 328K. J Chem Eng Data 40 43-64 Clegg SL, Rard JA, Pitzer KS (1994) Thermodynamic properties of 0-6 mol kg-1 aqueous sulfuric acid from 273.15 to 328.15K. Chem Soc Faraday Trans 90 1875-1894... 

A report on the ideal gas thermodynamic properties of sulfur heterocyclic compounds lists data on tetrahydrothio-pyran and 5,6-dihydrothiopyran <1995MI1351>. 

Kelley, K. K., Contributions to the data on theoretical metallurgy VII. The thermodynamic properties of sulfur and its inorganic compounds. U.S. Bur. Mines Bull., 406, 1937. 

L. V. Gurvich, I. V. Veyts, and C. B. Alcock, Thermodynamic Properties of Individual Substances, Vol. 1 Elements Oxygen, Hydrogen (Deuterium, Tritium), Fluorine, Chlorine, Bromine, Iodine, Helium, Neon, Argon, Krypton, Xenon, Radon, Sulfur, Nitrogen, Phosphorus, and Their Compounds, Pt. 1 Methods and Computation, Hemisphere, New York, 1989. 

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