Dissociation of oxides

The dissociation of Ag20 in oxygen was an early (1905) example (Lewis [640]) of a kinetic study of a solid state reaction and interest in 

While general agreement has been reached concerning the catalytic behaviour of the product metal in promoting reaction, other aspects of the rate process have been less satisfactorily characterized these include the changes which precede nucleus formation, the distribution of such sites and development of the reaction interface. 

The decomposition of silver(II) oxide in vacuum at 356—407 K exhibits a sigmoid a—time curve in which the deceleratory period predominates 

The sequence of decomposition intermediates formed varies with the particular preparation of reactant being studied. Gillibrand and Halliwell 

The second and the final changes may involve more than a single polymorph. There is thus the problem of identifying each rate process with a particular chemical transformation, and many reported inconsistencies remain to be resolved. 

---

Ahmed, S.M., 1966. Studies of the dissociation of oxide surfaces at the liquid-solid interface. Cane. 3. Chem., <14 1163-1170. 

According to the diagram, intermediates are formed by both heterolytical dissociation of oxidants (hydroperoxides, peroxy acids and iodosylbenzenes) ... 

A mechanism has been proposed for NADH-cytochrome bs reductase based on these elegant studies (Fig. 17) (308, 355). The hydrogen which is stereospeciflcally and directly transferred has been printed in boldface. Catalysis proceeds in a clockwise direction, and after the first catalytic cycle the dissociation of oxidized pyridine nucleotide and the association of reduced pyridine nucleotide are shown as a single step since both are very rapid processes and this emphasizes that the thiol is not (kinetically speaking) exposed during catalysis. The interaction of the thiol and the... 

Kosmuiski, M., Matysiak, J., and Szczypa. J., Solvent effects on standard thermodynamic functions of surface dissociation of oxides, J. Colloid Interf. Sci., 164, 280, 1994. 

Studies of the processes of dissolution and dissociation of oxide materials in ionic solvents, and the effect of surface properties of oxide powders on their equilibrium solubility. 

Pure oxygen-less melts contain no oxide ions in any form, and, therefore, such pure melts cannot serve as donors of O2-. The melts, which are solvents of the second kind, can affect acid-base interaction on their background in two manners by fixation of oxide ions entering in the melt and by solvation of the conjugate acid or base. However, the ionic solvents of the second kind, used in practice for different measurements and applied purposes, contain admixtures of oxide-ion donors, which are formed in the melt from initial admixtures of oxo-anions such as SO4-, COf- or OH-. The second way of appearance of oxide ion admixtures in molten media is characteristic of the melts based on alkali metal halides the process of high-temperature hydrolysis of the said halide melts results in the formation of hydroxide ions and, after their dissociation, of oxide ions ... 

As for studies of the dissociation of oxide-ion donors in molten salts, this is a very wide field. The behaviour of the strongest bases, such as peroxides and hydroxides, has not been studied in halide melts other than chlorides, and sulfate melts are not an exception. Data on the dissociation of carbonate ion in sulfate melts are not known. Therefore, if there are no data even for particular temperatures, to talk about the polythermal dependences of the corresponding dissociation constant is senseless. 

The law of mass action applied to these two equihbriirms is written indicating by xi the mole fraction of Al in eqitilibrium under pressure P of gas and at temperature T and by, respectively, PIi and II2 the two tensions of dissociation of oxidized forms AIG and A2G to form pure metals in their phases. The equihbrium conditiorrs are written as ... 

---