Gibbs energy of oxides

The theory of the accumulation of the Gibbs energy of oxidation of carbonaceous substrates in the form of the bond of the phosphate ion to... 

The first term on the right-hand side is in this ideal solution approach given by the standard Gibbs energy of oxidation... 

In some sources, the enthalpies of formation or the Gibbs energies of oxide compounds with several cations (silicates, aluminates etc.) are reported in terms of the reactions of formation from the constituent oxides. In such cases the data have been corrected with respect to the corresponding basic data of the constituent oxides presented in this work. 

Table 13.1 Standard Gibbs energy of oxidation reaction of group 4 and 5 metal carbides and nitrides (0.1 MPa, 298.15 K)...

There is a significant difference between rhodium and the odier metals in that rhodium forms a relatively stable oxide, RI12O3. The Gibbs energy of formation of this oxide is given by the equation... 

Appendix Thermodynamic data for the Gibbs energy of formation of metal oxides... 

The concentration of this species in liquid sulfur was estimated from the calculated Gibbs energy of formation as ca. 1% of all Ss species at the boihng point [35]. In this context it is interesting to note that the structurally related homocyclic sulfur oxide Sy=0 is known as a pure compound and has been characterized by X-ray crystallography and vibrational spectroscopy [48, 49]. Similarly, branched long chains of the type -S-S-S(=S)-S-S- must be components of the polymeric S o present in liquid sulfur at higher temperatures since the model compound H-S-S-S(=S)-S-S-H was calculated to be by only 53 kJ mol less stable at the G3X(MP2) level than the unbranched helical isomer of HySs [35]. 

Figure 6.15 Schematic cell using a stabilized zirconia electrolyte to measure the Gibbs energy of formation of an oxide MO. The cell voltage, E, is measured under open-circuit conditions when no current flows.

Figure 1.10 The standard Gibbs energy of formation from the binary constitutent oxides of the kyanite, sillimanite and andalusite modifications of A SiOs as a function of pressure at 800 K. Data are taken from [3]. All three oxides are treated as incompressible.

ArV is not necessarily positive, and to compare the relative stability of the different modifications of a ternary compound like AGSiOs the volume of formation of the ternary oxide from the binary constituent oxides is considered for convenience. The pressure dependence of the Gibbs energies of formation from the binary constituent oxides of kyanite, sillimanite and andalusite polymorphs of A SiOs are shown in Figure 1.10. Whereas sillimanite and andalusite have positive volumes of formation and are destabilized by pressure relative to the binary oxides, kyanite has a negative volume of formation and becomes the stable high-pressure phase. The thermodynamic data used in the calculations are given in Table 1.7 [3].1... 

In order to derive the phase boundaries in Figure 4.22 we need the Gibbs energy of formation of the oxides. This type of data is conveniently given in an Ellingham... 

Figure 7.15 (a) Enthalpy of formation of ternary oxides and nitrides from their binary constituent compounds as a function of the ratio of ionic potential [16]. Reprinted with permission from [16] Copyright (1997) American Chemical Society, (b) Gibbs energy of the oxide-sulfide equilibrium for group 1 and 2 metals at 1773 K as a function of the optical basicity of the metal. 

Figure 7.15(b) show the Gibbs energy of the oxide-sulfide equilibrium... 

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