V. N. KONDRAT’EV, N. N. SEMENOV, Yu. B. KHARITON. Electronic Chemistry. Edited and with a foreword by Academician A. F. Ioffe. Contemporary Problems of Natural Science, book 39. State Publishing House, Moscow—Leningrad, 1927, pp. VI + 160. Price 1 ruble 75 kopecks.

A characteristic feature of the development of theoretical chemistry over the last ten years, leading to such significant results, is the ever-growing cooperation between physics and chemistry. At the present time a considerable number of physicists are occupied with questions of the structure of the atom and the molecule—one of the fundamental problems of chemistry—while numerous chemists are making increasing use of purely physical methods. The union has taken place on the basis of the electron theory and Bohr’s atom; hence a new chemistry has arisen, based—in contrast to the old—not only on Avogadro’s rule and thermodynamics. One of the difficulties in this lay in the fact that the two sides did not always speak in a language intelligible to one another. A major shift in this respect was the historic congress of the German Bunsen Society for Applied Physical Chemistry in 1920, devoted to questions of the structure of matter and chemical affinity, at which the principal reports were given by physicists. Subsequently there also appeared a number of manuals on physical chemistry (Eucken, Eggert, and others), which devote attention to the methods and results of modern atomic physics.

For the further penetration of the new ideas into the milieu of chemists, it was important to unite, from a single point of view, the large body of experimental material accumulated in recent years. This is the task that the authors of the book under review set themselves, taking Bohr’s atomic properties as the basis of such a unification. The book is written in an accessible language and without a complex mathematical apparatus. Among the literature, the most recent works published up to September 1926 have been taken into account. Chapters I and II present the necessary data on the atom and the quantum laws. There follow, in Chapters III and IV, an exposition of the new views on valence, the nature of chemical forces, and the structure of molecules. The theory of the formation of Bohr’s polar molecules and the application of cyclic processes are described in detail. The question of the experimental verification of the numerical values of lattice energies, however, is not treated sufficiently fully. As for contem-

...attempts to explain the homeopolar bond, here, it seems to us, the authors have insufficiently appreciated the hypothetical nature of the ideas concerning the role of the electron pair. The chemist is also somewhat embarrassed when such “compounds” as PO or HgH are discussed. Here it would not have been superfluous to emphasize that their existence is concluded only on the basis of molecular spectra. Chapter V, which deals with collisions of the second kind, is well written. The work of Franck and Kalckmann on the excitation of mercury vapor in the reaction between sodium vapor and chlorine (and bromine) has not been analyzed quite accurately. Here, for example, it is not clear to which elementary process the energy taken as 99 large calories belongs, which also affects the subsequent considerations. Chapters VI and VII, which conclude the questions of structure and affinity, concern the theory of molecular spectra and the phenomena of deformation of the electron shells of atoms and ions. The last chapters (VIII, IX, X, and XI), perhaps the most interesting, are devoted to the second fundamental question—the kinetics of chemical reactions and related fields: chemiluminescence and ionization in chemical reactions, photochemistry and the electrical excitation of reactions, and catalysis. Alongside an excellent presentation of modern theories, we also find here a critical analysis of them, based on experimental material.

It must be acknowledged that, on the whole, the goal set by the authors has been achieved. The book is read from beginning to end with interest; without concealing many difficulties still not overcome, it nevertheless vividly demonstrates the fruitfulness of the new theory. The work of Kondrat’ev, Semenov, and Khariton will undoubtedly facilitate the penetration of new ideas into the community of chemists. We wish the book wide circulation.

P. K.