Current Problems in Nonstoichiometry

Abstract

years, in the sense that a fixed composition and a rational formula were taken as the definitive criteria for a compound. As applied to solid compounds, the law was not a generalization from experimental fact.The controversy between Berthollet and Proust was unsatisfactory; it was settled by a dogmatic, but natural, extrapolation of the conclusions drawn by Dalton from the atomic theory. These are inherently valid for discrete molecules. Until physical scientists were ready to think of crystalline inorganic compounds as infinite three-dimensional assemblies of atoms, the stage was not set for reopening this particular aspect of the recurrent problem of the strictly quantized or the statistical and quasicontinuous description of natural phenomena.

Defect Structure, Ionic Conductivity, and Diffusion in Calcia‐Stabilized Zirconia

“…is present as neutral calcium ionoxygen vacancy pairs or clusters. This fact seems to be quite reasonable in the light of the rather long-range character of electrostatic interaction between charged defects Ca2'-Tv'o 2" (18). But when the impurity (dopant) concentration and therefore also the defect concentration becomes as high as in CSZ, these treatments do not appear to be valid.…”

“…2a), so from Eq. 2 (~g --0.125) = 0.125.~(~) [18] Equations [17] and [18] indicate that from the conductivity data at x --0.0625 and 0.125, we can obtain the mobiiity ~(1-n and ~(2.2) inside the separate channels. 2 (~g --0.125) = 0.125.~(~) [18] Equations [17] and [18] indicate that from the conductivity data at x --0.0625 and 0.125, we can obtain the mobiiity ~(1-n and ~(2.2) inside the separate channels.…”

High-resolution microscopy of nonstoichiometric Nb22O54crystals: point defects and structural defects

“…The NbxzOzg-type Wadsley defect has not been discussed in the previous literature (for instance, Anderson, 1970) probably because no observation of the existence of a range of composition for the Nb22054 phase was reported until Kimura's study. This occurrence can be readily understood by extending the established concept of the Wadsley defects, i.e.…”

New Materials Design Using Excitonic Quantum Effects: Applications for Fuel Cells, Catalysts, Superconductive and Bioactive Materials

“…Disordering models (according to Andersen) [14] occupy an intermediate position between the two limiting hypothetical cases. The first of them corresponds to the highest degree of short-range and long-range order of defects, which leads to the replacement of the nonstoichiometric phase by a group of ordered structures close in composition with an insignificant concentration of defects.…”