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Monomeric and oligomeric spirocyclic compounds of the siloxane series, the methods of their synthesis, some of their physicochemical properties, and the reactions leading to their conversion into polymers of different structure are examined. The bibliography includes 69 references.

Results of the investigations in recent years on the gas phase thermal reactions of both inorganic and organic silylenes have been correlated. Particular attention has been paid to the sources used for generation of these unstable intermediates and also to methods of obtaining and to the properties of cyclic silylenes. The bibliography contains 62 references.

Results of the investigations in recent years on the gas phase thermal reactions of both inorganic and organic silylenes have been correlated. Particular attention has been paid to the sources used for generation of these unstable intermediates and also to methods of obtaining and to the properties of cyclic silylenes. The bibliography contains 62 references.

The synthesis of co-hydrolysates from metals and alkoxides at high temperatures (120–200 °C) affords a number of scientific and practical advantages.

A systematic account is given of data published up to 1975 on the preparation and chemical properties of silicon analogues of carbenes — short-lived bivalent silicon compounds (silylenes). Methods for their formation with the aid of high temperatures as well as other sources of energy (silent electric discharge, photolysis, and radiolysis) are discussed. The chemical properties of silylenes have been classified in accordance with three types: (1) polymerisation; (2) insertion in single bonds; (3) addition to multiple bonds. The possibility of employing silylenes (particularly dichlorosilylene) for preparative purposes is discussed. Attention has been concentrated on experimental data relevant to the gas-phase reactions of silylenes. The bibliography includes 299 references.

The results of studies on the synthesis of organosilicon heterocyclic compounds under the influence of high temperatures in a flow system at atmospheric pressure and in a high vacuum are surveyed. The preparative possibilities of the gas-phase thermal method for the synthesis of new or previously difficult to obtain mono-, bi-, and poly-cyclic compounds with one or several silicon atoms in the ring are examined. The principal aspects of the thermal heterocyclisation processes are described. Attention is concentrated on the synthesis of heterocycles with functional group substituents at the silicon atom as well as high-temperature reactions with participation of unstable intermediates: silylenes, sila-alkenes, and siladienes. The bibliography includes 130 references.

Studies on the direct syntheses of alkyl(aryl)chlorosilanes, which have served as a basis for the development of new ideas on the reaction mechanism formulated mainly in the last 2–3 years, are reviewed. The direct syntheses are used in the industrial manufacture of the most important organosilicon monomers. The new ideas on the mechanism proved to be extremely useful in determining the rules for the control of technological processes. The ideas concerning the specific role of chlorine transfer processes and the chain mechanism of the formation of alkyl(aryl)chlorosilanes which are discussed here were not dealt with in the previous reviews. The bibliography includes 204 references.

1. The effect of trichlorosilane on the direct synthesis of the phenylchlorosilanes is determined by its participation in the surface catalytic reactions for the formation of the desired products. For this reason the character of the effect is highly dependent on the activity of the contact mass. 2. A change in the formation rate and composition of the phenylchlorosilanes when trichlorosilane is added to the reaction zone is associated with a change in the concentration and composition of the intermediate products of the direct synthesis, namely, surface compounds of the SiCln type.