Despite this minor criticism, Hanack has written a vrtluable book which belongs on the shelf of every library, even though "Conformatianal Analysis" mity already be on that shelf. An to the mdividual chemist, he should probably make his choice between the two books rather than acquire both. E K N E ~L. T ELIEL Uniuersily of Notm Dame Nolre Dame, Indiana
Soma Aspects of Crystal Field Theory
Thomas M . Dunn, University of Michigan, Ann Arbor, Dmzald S. McClure, University of Chicago, and Ralph G. Pearson, Northwestern University, Evaaston, Illinois. Harper and Row, New York, 1965. viii 115 ~ p .16 X 24 cm. Clothhound, $6: paperbound, $3.95.
+
As was argued with Shavian wit (THIS JOURNAL,41, 466 [1964]), the model for transition metal complexes presented by electrostatic crystal field theory using the point charge approximation, while allowing albeit rather successful treatment by convenient mathematical methods, in fact deals with s. wholly mtificial analogue of the real problem. Thus as good scientists we are behooved to discard this model with its fortuitously correct results, especially in tho face of the availability of a well-worked out alternative in molecular orbital theory. The general t,heoretical treatment embodied by both approaches is now firmly established in undergraduate courses of inorganic chemistry and simplified explanations are about to filter down into the freshman
actual chemical systems is now a matter of concern to teachers and students dike. The slim volume of 115 pages including index under review is the transcript of s. series of lectures given on crystal field theory a t the University of Michigan in 1962. Thomas M. Dunn of Michigan, Donald S. McClure of Chicago, and Ralph G. Pearson of Northwestern participated in the series which included discussions of spectral, magnetic, thermodynamic, and chemical kinetic a3peet.s of crystal field theory. McClure and Pea-son gave the thermodynamics and kinetics talks respectively with Dunn handling the theoretical development. I t is difficult to i m ~ i n ewhat accounted for the delay of three years in publication, As it stands, only one reference to the original literature is from as late as 1963. Some idea of the failure to change the manuscript to include later work can be gathered from the "in press" reference to J . Am. Chem. Sac. a t (,he end of Chapter 5 (reference 10). The paper appeared in the March 5 issue of 1964; "Some Aspects of Crystal Field Theory" was published in August, 1965. Even more seriously, the discussion by MeClure of inner orhit,al effectson thermodynamic properties is given more thorough treatment in his review article with Philip
224
/
Journol o f Chernicol Education
George in Progress in Inorganic Chemislq ( I , 381 [1959]). Of the seven figures in this chapter, five are taken from the 1959 review article. Apart from the question of whether the long wait for publication ha- st,aled the contents, readers looking for a stroug statement of comparison concerning the similarities and difierenees which contrast the two approaches may he disappointed. While ligand field theory is dealt wit,h by Dunn in the first chapter on t,heoreticd aspects and a brief summary of some of the evidence for covalent interact,ians given there as well as in the discussion of chargetransfer spectra, and again hriefly a t the ends of the chapters by MeClure and Pearson, it will seem to many that insufficient space is devoted to that evidence which refuses to fit into the f r a m e work of simple cr.ystal field theory, and more particularly that a clearcut distinction is never made between what is called ligand field theory (which might better be restricted to minor modification of crystal field energy level diagrams such as reduction in the interelectronic repulsion parameters, and regarding the radial part of the d-wave functions as a variable parameter, etc.) and the molecular orbital theory for transition metal complexes. What the seminar series tries to do, however, is well-done. St,udents a t the graduate level will find t,he book a concise introduction and manv seetiam extremelv
example, he treats in juxtaposition ( I ) the separation of the rare earths with an snion-exchange resin and an eluent of nitric acid in s. mixture of ethanol and water, ( 2 ) the separation of hydrochloric and acetic acids with a, cation exchanger and water ss eluent, and ( 3 ) a. mixture of ethers with a cation exehrtneer and water as eluent. There is indeed a. close relationship between thwe methods. A large smount of useful data is given graphically hoth throughout the text and in the appendix. The author has done a real service bath to the general reader and to the expert in presenting in one hook sepsrstions on large and small scales for both analyticel and prepsrative purposes, together with well chosen topics on the fundamental properties of ion-exchange resins and the mathematical theories of these seuarations. This service could
c*re. Although the paper and printing are generally good, broken type and wrong symbols appear in some critical places. In the mathematical equations on p. 257, there are seven broken subscripts. One of these is almost invisible, and the reviewer suspected its presence merely by the unusually long space between the preceding and following symbols. At intervals of about 20 pages, a t the end of each section, there is a list of references, aver 200 in one ease, arranged by topics and ehronalogieslly within each libraries. topic. There are no symbols within the J. J. Z U C I ~ K M A N text by whieh the contribution of each referenceisidentified. Thusthereaderwho Cornell University mity wish more information on the kinetics Ithaca. New York of ion exchange, for example, may have to consult all 94 references dealing with the topic before he finds the specific information that he desires. This is aggravated by the almost romplete absence of authors' names in the diacussiona. There is no alphabetic list of authors. Les ¶tions par ler resines Mathematieel equations are handled &hangevses d'ions almost as badly. Very few me numbered. Import,ant ones are emphasized by being B. T r h i l b n , Facult6 des Sciences de printed in a black rectangle with or withParis. Gnuthier-Villars, Paris, 1965. out a number. When the author wishes to 400 pp. Figs. and tables. 16 X 25 cm. refer to a previously given equation, he 90 F. denotes the page number; generally there are several equations on this page. I n accordance with the title of this Eoustion 13) . , on uaee 170 is followed bv book, the author includes both anslytieel eleven unnumbered equations and then by and industrial separations and excludes equation (6). nonresinaus ion exchangers, such as the liquid and inorganic exchangers and the The author does not give an equation derivatives of cellulose. IIe also wisely for the minimum height of column required for the separation hy elution of two includes three chapters (133 pp.) on the ions of known distribution ratios. Instead, fundamental properties of ion-exchange he gives on t,he bottom of p. 233 a n implicit resins. He states in t,he preface, "The mathematical theories have not been equation for No, the minimum number of developed thoroughly [in this book], and plates. This equation appears t,o he we have explained only the essentials of explicit; but No appears on hoth sides those that are m o t useful for the comprebecause vi, the interstitial volume, is a hension of the phenomena even if they are function of the column height and hence not the most rigorous." Therefore the of NO. A much simpler and mare aereader who is not an expert in ion exchange curate equation for the minimum height will find the derivation of some equations has been published. very difficult, but he will be able to use the final equations to solve problems. WILLIAMRIEMAN, 111 The author has a keen insight into the Rutgers, The Slate University properties of ion-exchange resins and their n'ew Brunswick, .Vw Jersey use in chromatographic separations. This enables him to see similarities between apparently unrelated separat,ions. For (Continued on page AS641
."
