Multiple oxides point defects

In last century the knowledge of defects in a solid, especially an oxide, has been explored comprehensively. The contribution of Schottky and Wagner successfully put the problem on a quantitative basis and promote the discovery of semiconductor transistor. The idea of non-stoichiometry was developed by Berthollet more than a hundred years ago and the controversy between berthollides, which do not obey the Dalton s law, and daltonides, which follow Dalton s law of constant and multiple proportions based originally upon the study of simple ionic and molecular species, encouraged the scientific debates on how existence of point defect in a compound is is it random statistic distribution or the structure related The experimental data are the best way to explore the truth. Indirect and direct observations of atom... 

The second-generation point defect model (PDM-II) [39] addressed the deficiencies of the previous model by incorporating a bilayer structure of the film consisting of a defective oxide layer on the metal surface and an outer layer that is formed by precipitation of products firom the reaction of transmitted cations firom the underlying metal with species in the environment. PDM-II assumed that the barrier layer controls the passive current and recognized the barrier layer dissolution and the need to distinguish whether the reactions are lattice conservative or nonconservative. The model also introduced the metal interstitials to the suite of defects. The model is in agreement with experimental results. Model PDM-III extends the apphcation of the PDM model and addresses the formation of multiple passive layers at the outer layer [40]. 

The common point of view has been widely accepted that oxidative stress results in multiple defects in cellular structure and, thus, is damaging for cells, tissues and the body. Nowadays accumulated information allows to accept another concept (which, by the way, is close to that of Hans Selye who introduced this term to modem biology) — that oxidative stress is a way to mobilize adaptive and protective mechanisms of the organism to survive under extreme conditions. 

Others, C and D, the ratio of the quantity of C which saturates A to the quantity of D which saturates A is also the ratio of the quantities of C and D which saturate B (a statement of the law of reciprocal proportions). He proved the law of multiple proportions (he does not use this name) for the three oxides of lead (PbO, Pb304, PbOg), the oxides of copper and iron, sulphurous and sulphuric acids, neutral and basic salts of copper and lead, sulphides of iron, and some salts and showed that the ratio of sulphur to metal in ferrous and lead sulphates is the same as in ferrous and lead sulphides (the latter is converted completely into sulphate by oxidation), which confirmed Richter s law, which he supposed held good generally. In lead sulphate the oxygen in the base is just one-third that in the acid [PbS04=Pb0 + S03]. All these results confirmed Dalton s theory. All the defects in Berzelius s analyses are clearly pointed out. 

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