Table of contents

In its electronic effect phosphorus(III) is usually regarded as an analogue of tervalent nitrogen. However, in recent years it has been shown that substituents with phosphorus(III) do not exhibit a π-donor effect, which is characteristic to a greater or smaller extent of groups containing the elements in Periods II and III with lone pairs of electrons. On the other hand, substituents with phosphorus(III) exhibit a π-acceptor effect, characteristic of meta-orienting groups, and probably due to the interaction with the vacant orbitals of phosphorus. Thus, in contrast to elements of Periods II and III with lone electron pairs, phosphorus(III) is incapable of p–π conjugation. The absence of the capacity of the lone electron pair of phosphorus to undergo delocalisation (or the presence of only insignificant capacity of this kind) has been explained by an enhanced s-character of the lone pair orbital, which is confirmed by data for the valence angles in phosphorus(III) compounds. The physical and chemical properties of phosphorus(III) compounds in which there is a possibility of p–π conjugation are discussed in the review from this standpoint. All the properties are consistent with the hypothesis of the predominant s-character of the lone electron pair of phosphorus. The bibliography includes 361 references.

The review discusses the reactivity of organic derivatives of the elements (with one or two "non-organic" atoms) in relation to halogenomethanes. The chemical reactivity of true organic derivatives of elements in Groups I–V in reactions with alkyl halides is determined by the type of the compound and the nature of the element–carbon bond. Particular attention has been devoted to initiated processes. The bibliography includes 250 references.

The studies dealing with the elucidation of the detailed mechanism and quantitative kinetics of the reactions of peroxy-compounds with phosphites, sulphides, and aromatic amines are reviewed. It is shown how evidence has been obtained by ESR of the existence of the one-electron amine oxidation stage, i.e. the stage involving the formation of radical-cations. The consecutive reactions of the radical-cations formed initially and their relation to the behaviour of the amines as polymerisation initiators are analysed. The characteristics of the detection of free radicals in reactions of phosphites and sulphides with hydroperoxides are examined and certain criteria of the latent radical nature of these reactions are formulated. In the last section correlations of the Hammett equation type for rates of the reactions under consideration and also the correlation between the rate constants on the one hand and the ionisation potentials and electron affinities on the other are discussed within the framework of the one-electron oxidation–reduction mechanism. The bibliography includes 96 references.

The review deals with the possibility of using various physicochemical characteristics of the hexafluorides of p, d, and f elements for a comparative estimation of their thermal stability and reactivity. The force constants of EF₆ molecules, the average bond energy and length, and also the thermodynamic stability constants of the octahedral EF₆ molecules have been used as characteristic properties. It has been shown that the force constants of the E–F bond are not effective characteristics of the thermal stability and reactivity of all hexafluorides in reactions where more than one E–F bond is dissociated. Only the thermodynamic stability constants can serve as an objective criterion for the assessment when account is taken of definite dissociation mechanisms of EF₆ molecules (complete or incomplete dissociation). Within the limits of individual groups of 4d, 5d, and 5f elements and also sulphur, selenium, and tellurium, the variation of the force constants and thermodynamic stability in relation to the incomplete dissociation of the hexafluorides corresponds to the experimental sequences of their thermal stabilities. The bibliography includes 85 references.

Data published in the Soviet and foreign literature on alkali and alkaline earth metal ozonides are described systematically and critically discussed. The methods of their preparation, physicochemical properties and reactivities have been examined. Certain concepts concerning the mechanism of the formation of ozonides have been presented. The bibliography includes 87 references.

A systematic account has been given of the information currently available about the components of the hyperfine coupling tensor of fluorocarbon radicals and also information about the form of the spectra of fluorocarbon radicals containing one and two α-fluorine atoms in polycrystalline specimens. Recent information on the paramagnetic centres in irradiated polytetrafluoroethylene, including fluorocarbon radicals and also radicals formed in their oxidation, is presented. The bibliography includes 24 references.

This review presents the most rational and widely employed methods of qualitative gas-chromatographic analysis of complex organic mixtures. The bibliography includes 147 references.

The review gives a consistent description and analysis of the ideas underlying the determination of potential constants (coefficients of the potential function formulated as a power series in terms of generalised coordinates) for diatomic and simple monatomic molecules using quantum-chemical methods. Calculations for specific molecules of greatest interest both theoretically and practically are briefly considered; the results of these calculations are presented in the form of tables. The bibliography includes 80 references.