Electronic structure of molecules (Linnett, J. W.)

FRED C. ANBON. California Institute of Technology. Pasadena. Molecular Orbitol Theory. C. J. Ballhausen, University of Copen- hagen, Denmark, and Harr...
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possible; but then, the reader is referred to the original papers without being able t o guess Delahay's opinion of the origind papers. It is no exaggeration to say that this is the most important monograph on electmchemistry to appear since "New Instrumental Methods in Electrochemistry" was published in 1954. It could readily serve as a text for a year-long advanced course in electrochemistry. The book will be indispensable as a reference for a11 researchers in electrochemistry and electroandytical cbemistry. FREDC. ANBON California Institute of Technology Pasadena

presentation to students, although the papers were originally written for a different purpose. Because of its method of presentation - typescript - the textual matter is relatively inefficient in the use of space, while some of the reprints are reduced to such an extent as to be hard to read. In the second chapter the authors introduce energy level diagrams (Fig. 217b, 2-19) suggesting s. reversal of energies from the generally presented scheme due to substantial s-p mixing. The scheme seems unconvincing; one would like to see some reference to detailed calculations. In summary then, the book is a typical example of this series, with all its strengths and weaknesses. The overly naive approach may a t times be misleading. In spite of these weeknesses, the book p r e sents a somewhat novel approach and may well become useful in dealing with advanced undergdtdustes.

Molecular Orbitol Theory

C. J. Ballhausen, University of Copenhagen, Denmark, and Harry B. Gray, Columbia University. W. A. Benjamin, 273 pp. Inc., New York, 1964. ix Figs. and tables. 16 X 23.5 em. Clothbound, $9; paperbound, $4.95.

H. H. JAFFB University of Cincinnati Cincinnati, Ohio

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This is another volume in Benjamin's Frontiers in Chemistry series. According to the preface, the book "is based on lectures on molecular orbital theory . designed primarily for advancedundergraduate and first yeargraduatestudents." In distinction to most other recent texts in this area, the molecular orbital method is applied primarily to inorganic compounds; conjugated r-electron systems are completely ignored. Symmetry considerations are early introduced to simplify the treatments. This reviewer, although far from a purist, feels that the authors have possibly gone too far in the use of "our intuitive approach in the use of symmetry methods [which] is admittedly nonrigorous and . will be unsatisfactory to purists.. ." The first two chapters introduce atomic orbitals and the MO's for diatomic molecules. After a brief excursion into general matters-Electronic States, Hybridimtion and Band Intensities-the authors focus attention on a series of small mole cules-CO~, H90, NO2, Os, SO2, H.Os H&O, BzH~.The final chapter is a discussion of transition metal complexes. A series of appendices deals with a number of important mathematical problems. The format of this book is the one now familiar in tbis series. The main text is photo-offset from typed manuscript, and close to half the pages, but a substantially greater fraction of the text consists of "selected reprints of pertinent papers." This reviewer wonders whether such a highly informal, though marvelously rapid and economical, method of preparing a book does not tend to lead to a text which is overly informal, and, in spots, nonrigorous. The system of using about half the space for reprints of papers makes the selection extremely important, and assumes, maybe not always correctly, that papers, most of which are from 10 to 30 years old, still present the best available treatment, or the best treatment for

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compounds of Cr(0)-Cr(V1) with neutral ligands and ligands forming inner complexes. Aquo complexes and compounds with acidic ligands are covered in Chromium, Part B. After preliminary classification by valence state, the many Cr(II1) complexes are typed as (CrLdP+,(CrXL6)q (CrXr Ldi, (CrXbLa),and (CrX,LJ-, where L represents a neutral ligand and X an acidic ligand. A chapter on inner complexes is classified according to the organic ligand. Theoretical asoects of electrostatic and

and the chromated a m dyes. This volume concludes the coverage of chromium in the eighth edition of Gmelin.

J. V. D.

Gmelins Hondbuch der Anorgonischen Chemie. 8. Auflage, System Nvmmer 16, Phosphor, Teil A

Edited by E. H. E. Pietsch and the Gmelin Institute Verlse Chemie. GMBH, Weinheim/~er~s&se, 1965: 510 pp. Tables. 17.5 X 25.5 xii em. 5116.

Physical Chemistry

E. A. Moelwy-Hughes, University of Cambridee. - . Endand. 2nd rev. ed. Pergamon Press, Inc., Long Island City, 1334 pp. New York, 1964. vii Figs. and tables. 16.5 X 25 cm.

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The second revised edition (1964) of tbis book does not differ in any important way from the second edition (1961) or, indeed. from the first edition (1957).

provide even a useful introdudion to the new topics; thus, nuclear and electron spin resonance spectroscopy receive three and one-half pages. Despite such minor face liftine the bulk of the material has not been revized and most references in the book are to work prior to 1955. The advantages of the book remain its strong mathematical approach, unified viewpoint, freedom from errors and skillful blending of experimental data and theory. Its greatest disadvantage is the fact that it is now often quite out of date and the references fail to provide an introduction to the current literature. I t will continue to be useful as a reference work but will not be a satisfsetory textbook for most physical chemistry courses in this country. MAXT. ROGERS Miehigan State University East Lansing Gmelinr Hondbuch der Anorgonischen Chemie. 8. Aufloge, System Nummer 52, Chrom, Teil C

Edited by E. H. E. Pietsch and the Gmelin Institute. Verlag Chemie, GMBH. Weinheim/Berestrasse. 1965. xliii 431 pp. Figs. and 'tables. 17.5 X 25.5 em. 5102.

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This volume includes the literature published up to 1960 an the coordination

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The history of phosphorus and its occurrence in nature are the topics covered in this volume. Most of the book is devoted to the occurrence of the element. This section is updated to contain chapters on extraterrestial occurrence, phosphorus in the hydrosphere, and phosphorus in the biosphere. Considereable space is rtho given to the phosphorus containing minerals.

J. V. D.

Electronic Struclure of Molecules

J . W. Linnelt, Oxford University. John Wilev and Sons. Inc.. New York. 1964. vii i 167 pp. ' ~ i g s :and tables.' 14.5 X 22 cm. $4.75. This book is one of the most important ever published in the field of chemistry. The ideas in it, when combined and integrated with those of R. J. Gillespie, can revolutionize the theory of the chemical bond. Until recently, valence-bond theory has had two principal weaknesses: first, the apparent necessity for the hybridization of atomic orbitah, and second, the a p pasent necessity for resonance in describing certain molecules. The firat of these weaknesses is eliminated if one accepts the theory of valenceshell electron-pair repulsion, which, as developed by Gillespie (THIS JOURNAL, 40, 295 [1963], and others), makes hybridiaation unnecessary. Linnett's book makes possible the elimination of the second weakness of the vdence-bond approach. Although Lin-

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nett states only that the need for resonance is much diminished by his theory, a slight modification seems to he all that is required to eliminate resonance entirely. Such a rash statement may seem shoekingly heretical to many readers of this review, but 8. thorough study of the r e markahle triumphs Linnett has already scored in his book shonld persuade most of them to join the heretics. A theory that can give beautifully simple explans, tions of the structure and behavior of OP, Oa, NO, NO%and-perhaps most convincing of alll--of the benzene ring deserves careful consideration. The principal change required in Linnett's approach is to admit that the octet is not sacred. Most chemists now agree that no octet is involved for the central atom of molecules like BeC12 and BClr. If they can also agree that, in addition to Be and B, two more atoms of the second period, namely C and N, in some of their compounds, can also have less than eight electrons ia their valence shells, resonance is dead. I n Linnett's book there is no sanctity for the electron-pair. Although his theory predicts that most molecules are held together by electron-pair bands, it postulates that other types of bonds may he equally important. For example, the C C bond in CIHl consists of two electron-pairs; but in CnHnnone of the six electrons of the C C bond is closepaired. Thus we must now learn to talk about &electron bonds. Furthermore, because all the electrons in either hond are equivalent, r electrons are outmoded. In the paramagnetic oxygen molecule, containing five valence electrons of one spin and seven of the opposite spin the two atoms are held together by a 4electron bond-none of the electrons being close-paired. In the oeone molecule, each pair of atoms is held together by s. 3electron bond-again with none of the electrons paired. Probably the most striking success of Linnett's new approach is its solution of the long-standing problem of the benzene ring. The carbon atoms are held together by 3-electron hontis. In each bond, the three electrons me equivalent, with none in close pairs, which means no T eledrons. As already indicated, the principal flaw in Linnett's theory is that he is unwilling to abandon the octet. At the bottom of page 26, he even states that the octet rule includes all the elements of the second and third periods (Li-Ne and Na-Ar), thus ignoring the many well-known exceptions to his statement such as BeCL, BCI,, B P HPFE, ~ and SF.. This flaw makes unsatisfactory Linnett's proposals for the structures of NO*, NOI-', Cos-: and other molecules or ions involving C and N. If he would abandon the longdiscredited oetet rule, ss he has already diminished the importance of the electron-pair, his ideas could be combined and integrated with those of Gillespie to make possihle a major advance in the theory of the chemical hond. Everyone associated with chemistry should buy this book and study it thoroughly. Most who do so will enjoy thrills

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of excitement in following the author's beautiful solutions of some perplexing problems of the chemical hond.

Introduction to Quantitative Chemistry

Joseph A. Klingenberg, Xavier University, Cincinnati, Ohio, and Kenneth Reed, Villa Madonna College, Covington, Kentucky. Reinhold Publishing Co., New York, 1965. 352 pp. Figs. and tables. 16 X 23.5 cm. $6.50.

Upon first examination the reviewer believed that this might prove to be an exciting text. There is a need for new texts in quantitative analysis to conform with present practice--namely, to present material for a 0nBsemester coune early in Electronic Structure and Chemical the curriculum whioh includes tbe more Bonding tmditional approach as well as the introDaald K . Sebera, Wesleyan University, duction of the newer methods of separaMiddletown, Connecticut. Blsisdell tion, etc. The second course, normally Publishing Co. (a division of Ginn and "instrumental" in flavor, frequently does 298 Co.), New York, 1964. ix not immediately follow the h t coune and pp. Figs. and tables. 13.5 X 20.5 texts need to he written to recognize this cm. Paperbound. $3.50. fact. Many texts are designed for a oneyear course. Some are too bulky in their This is another in the rapidly increasing attempts to be comprehensive but still are number of books on elementary aspects inadequate for courses in "instrumental of chemical structure. As such it must andysis." stand comparison with (among others) A critical study of the text, however, Companion, Ryskewitch, Brown, Seel, revealed a number of shortcomings, many Cartmell and Fowles, Barrow, Grpy, of them related to the fact that "text size Orgel, Pauling, and Caulson. In this hst, hss been kept small by adopting a semiwhich is approuim~telythat of increasing outline form of presentation." This form rigor and (eo-incidentally?) quality, I of presentation has resulted in certain would, on both counts, place Sehem's omissions such as a good description of new volume just before that of Certmell titration error or the effect of direction of and Fowles. titration upon results. The reviewer BY now the contents of t h a e books are could not find directions for the preparafairly standard and so it is here. The tion of the indicator solutions used. final two chapters-The Metallic Bond A number of misleading, incomplete, or and Semi-conductors and Weak Forceserroneus statements or passages were Weak Bonds-however, are relatively found in both the chapters on theory and novel and quite successful. laboratory exercises. These points of The book is written in clear, if somewhat fault are such that in many cases a. chemist pedestrian, language, though one would would recognize them for what they were wish that extended analogies (such as the worth, understand what is meant, and soft-drink machine) could be kept where dismiss them as just poor or incomplete they belong-in Lecture. And if we must wording, etc., but a student does not have have a zoological analogy far a resonance the professional skill to distinguish behybrid surely Wheland's mule is better tween truths and half-truths, completeness than its later "progeny," Brown's hiand incompleteness. Space does not pernoceros. There are s, number of errors but mit more than a sampling (italics mine): these are mainly trivisl. It was Newlands, (1) In the Preface it is stated as one of four not Mendeleef, who was asked (by Carey unit operations, "Isolation of the desired Foster) if he had tried arranging the eleconstituent in a measurable form"; folments in alphlphabetical order. Uhlenbeek . .they form lowed by the statement, and Goudsmit did of course propose the the basis of all andyses. This s t a t e spin of the electron but not on the basis of ment is not true. (2) On p. 22 in a disthe experiment described on page 30. cussion of the methods of weighing by The meaning of the word "degenerate" transposition, "The true weight is then on page 22 is not the usual one though it equal to the square root of the product of is clearly defined. the two weights. If the two weights m e The proliferation of paperback suppleahout the same, the true weight is simply mentbry texts raises the question of their the average of the two weights." What is place in the chemical curriculum. In the meant by true weight? (3) Onp. 107, "An preface Professor Sebera states: "The ordinary buret can be read to four signifitopics discussed are all included in the Wesleyan University freshman chemistry cant figures. . " Can one read volumes course elected by students with or without less then 10 ml. to four figures? (4) On p. 153, .it is desirable to consider the previous secondary school courses in definition of an acid and a base." The chemistry and physics." And yet by page approach developed in this passage is apt 27 we are into the quantization of magto be puzzling to the student. (5) In the netic moments. Such prefaces and suoh directions for the standardization of hydrosequels are now so common that the rechloric acid against sodium carbonate it is viewer sometimes wonders if be has in his underprivileged hands the last members stated, "Place about 5 g of.. sodium carbonate in a crucible and heat for about of an almost extinct species: the average ' 1 2 hour a t 200°C." Do you heat in an freshman student. oven or over a. gas &me? Using a flame, DEREKA. DAVENPORT how does one know if he is beating a t Purdue University Lafayette, Indiana (Catinued a page A68)

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