THE ELECTRONIC CONCEPT ON OF VALENCE AND THE CONSTITUTION OF BENZENE BY HARRY SHIPLEY FRY, PH. D. PROFESSOR or CHEMISTRY AND DIRECTOR OF THE CHEMICAL LABORATORY UNIVERSITY OF CINCINNATI WITH DIAGRAMS LONGMANS, GREEN AND CO. 39 PATERNOSTER ROW, LONDON FOURTH AVENUE 30TH STREET, NEW YORK BOMBAY, CALCUTTA, AND MADRAS 1921 TO MY WIFE PREFACE. THE electronic conception of valence as developed and applied in this monograph is concerned neither with the question of the ultimate nature of chemical affinity nor with the intimately related problem of the constitution of the atom The variety of hypotheses now current, which deal with the constitution of the atom, has signally failed to furnish a uniform valence hypothesis which will enable chemists to elucidate chemical formulae and re actions, or, in other words, to present more complete pictures of the relationships existing between the chemi cal constitution of substances and their chemical, physico chemical and physical properties After studying the many anomalous hypotheses on atomic structure and valence, the author has adopted the early and relatively simple suggestion of Sir J J Thomson that if we interpret the bond of the chemist as indicating a unit Faraday tube, connecting charged atoms in the molecule, the structural formulae of the chemist can be at once translated into the electrical theory . Accordingly, the symbol a short straight line between atoms which indicates a bond in a structural formula, assumes an added significance since one end of the bond corresponds to a positive, the other to a negative charge, through the transference of an electron from the one atom to the other. This, briefly, is the electronic conception of positive and negative valence which is employed herewith, solely as a formulate hypothesis. It is applied to the formula of many substances but chiefly to the constitution of benzene. THE ELECTRONIC CONCEPTION OF VALENCE, Methods are proposed and fully illustrated explaining how structural formula may be translated into electronic formula but only when it may be clearly demonstrated that the resultant electronic formulae possess greater significance in interpreting and correlating chemical and physico-chemical phenomena than do our customary structural formulae The monograph is divided into four parts. Part I develops the electronic conception of positive and negative valence as a formulative hypothesis in chemistry Part II. relates paiticularly to the constitution of benzene and its derivatives, and to the problem of substitution in the benzene nucleus Part III deals primarily with physical and physico-chemical properties, notably, molecular vol umes, absorption of light and fluorescence Part IV. considers the constitution of the metal-ammmes and presents a bibliographical and chronological review of those articles of authors who have presented applications of the electronic conception of valence Concordant with the fact that the preface is usually the last part of a book to be written, a more comprehensive preface may be found in Section A of the final chapter In conclusion, I am deeply grateful to my colleague, Dr Earl F. Farnau, lor valued suggestions, criticisms, and his reading of the manuscript, and also to Miss Eva Hauck, Secretary of the Department of Chemistry, University of Cincinnati, for the preparation of the index of names and the transcription of the manuscript. UNIVERSITY OF CINCINNATI, CINCINNATI, OHIO, i th May, 1920 CONTENTS. CHAPTER PAGE PREFACE . vn PART I. THE ELECTRONIC CONCEPTION OF VALENCE CHAPTERS I - VI T INTRODUCTORY . .3 II THE ELECTRONIC CONCEPTION OF VALENCE 7 A Fundamental Conceptions Su J J Thomson, Baly and Desch, Sii William Ramsay , . y B. Electronic Formulae of Diatomic Molecules Elect rodualism Berzelms, Helmholtz, Walden, Thom son, Noyes . 9 C Electronic Isomers or Electromers A new type of isomensm . 1 1 D. Electionic Tautomerism A new type of tautomerism . ... --This text refers to the Paperback edition.