X-ray diffraction in crystals, imperfect crystals, and amorphous bodies

Hammond strive to bring unity to a potent,ial chemical Babel. The vvlume continues with eight artirles written by the foremost contribut,ors to the va...
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niques, and the increased interest in the problem of energy transfer and exeited states have brought attention to photnchemistry and have given the chemist the means oE investigating "the detailed history of a molecule which absorbs radiat,ionU whieh the editors of this new serie~ consider to be the fundamental photochemical problem. The authors of the first article recognize one of the distinct difficulties of a field which has developed from diverse areas. The "vocnb~~lary" of photoehemist,r,y tends to be a mixture of d l the speeialiaed languages and Pitts, Wilkinson, and Hammond strive to bring unity to a potent,ial chemical Babel. The vvlume continues with eight artirles written by the foremost contribut,ors to the various aspects of photoehemistry. The Photoehemistry of Aromatic Hydrccarbon Solutions is discussed by E. J. Bowen. The problems current. in this field are analyzed bnt the lack of a table of contents preceding the article makes some of the material difficult to find in the body of the text. The gas phnee photochemistry of the hydrogen-oxygen system is the subject of a review by D. H. Volman. The author carefully reviews t,he status of the understanding of the reactions and unresolved mechanisms in this system. R. Srinivasan follows with the Photoehemistry of the Cyclic Ketones which mainly deals with the 4 to 7-nremher ring system in vapor and condensed phase. The status of the gas phase addition of atoms to olefins is next discussed in great detail by R. J. CvetanoviC. Alt,hough the reactions of oxygen atoms occupy ahout half of the author's attention, he does not neglect hydrogen, halogen, carbon, nitrogen, and sulfur atoms in his discussion. I n A Xew Approach t o Mechanistic Organic Photochemistry, H. E. Zimmerman considers the nature of the electronirally excited species which is formed as a consequenre of the absorption of the light quanta by the ground state. The presentation is lively and will undoubtedly arouse considerable interest. Gunning and Strausz are concerned with the mechanism of energy transfer in merrury photmensitiration and the use of isotope effects to aid in that understanding. Their treatment of kinetic isotope effects, although dealing only with hydmgen-deuterium, is quite comprehensive and t,he inclusion of references as recent as Spring 1963, gives the paper a "hot-offt,he-p-" quahty. Photochromism, the reversible color changes which certain aubstmces undergo upon exposure t o light, is the topic of the review by Dessauer and Paris. They catalogue a large number of chemical systems which exhibit this phenomenon and discuss the changes in physical properties whieh accompany the color change. The final paper, Photochemical Resrrangements of Organic Molecules by 0.L. Chapman, is a 90-page study whieh offers to its readers a survey of a great deal of organic chemistry from simple keto-end isomerisation to the photochemical trmsformations of the Vitamin D series. There is s sense of urgency about the article reflected in the fact

that the majority of the 225 references cited deal with papers published in 1960 or later. For the organic chemist there is a rirh source of interesting rearrangements which might otherwise have been lost in the onrush of the literature. An extensive author and subject index fnllows the articles. If this volume is represent,ative of those to come in this series, then a serious gap in t,he literature af photochemistry will have been closed with some exciting writing by pioneers in the field. I highly recommend this volume ss a valuable reference hook to all who are interested in energy transfer, the chemistry of excited statet, and the many aspects of photochemistry. This series is long overdue and its appearance in this form is most welcome.

cedure, rhoice of wavelength, methods of standardiaation and measurement, de, tection limits, and errors and interferences. The latter topics are particularly well treated. Detection limits are given s sound definition and s. tsble of limits for all elements determinable (up to mid1962) is presented whieh includes several wavelengths for each element in a variety of flames using both wrtter and nonqueous salverrts. Interference mechanisms and instrumental and procedural techniques for minimizing interferences m e very w d treated although only the most important, (alkali metal cation-cation and alkaline earth) are discussed sp~eifiedly. The chapter on applications is short and cursory except for the eection on medicine and biology where blood analysis is described in some detail. References to $1 Z.HOFFMAN specific analytical applications that are in MORTON Boston University the bibliography are included in the index, Boston, Massachusetts whieh is excellent,, and they are easily located. The appendix contains very extensive wavelength tabIe,les and intensity data for atomic and molecular flame emitters, both bv element and bv wavelenpth. Alao in-

Chemical Analysis by Flame Photometry

Roland Herrrnann, University of Giessen, Germany, and C. T. J . Alkemde, University of Utrecht, Holland. Translated by Paul T. Gilbert, Jr., Beekman Instruments, Inc., Fullerton, California. 2nd rev. ed. Interscience Publishers ( a division of John Wiley and Sons), New York, 1963. Chemical Analysis Series, 644 pp. Figs. and Volume 14. xiv tables. 16 X 23.5 em. $00.00.

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This monograph is the mast complete and up-to-date volume on flsme photametry readily accessible in this country and represents a fine addition to the Interscience series on Chemical Analysis. The authors are concerned with a critical evaluation of instn~mentationand analytical techniques and with the fundamental processes and reactions involved in flames and flame analysis. It. is not, and is clearly not intended to be a handbook of procedures and applications. The book begins with a discussion of the structure and properties of flames and reactions of analytical importance oceurring in them. I n this ehspter are also outlined in detail the various types of interferences occurring in flame photometry and their interdependence. This section is of particulas value because of the confusion surrounding the description and explanation of interferences that exist in t,he literature. One may disagree with details of their organization here but it is consistent, and it is helpful t,o have the terminology and definitions presented clearly and concisely at the start. A long chapter is devoted t o experimental variables and instrumentation. Components of flame photometers, spectrophotometers, and spectrographs and the variables involved in their onoration

amplifiration is given ts very brief treat. ment. Chapter 4, on analytical techniques is the heart of the text, containing detailed and critical discussions of andytical pro-

characteristics. A drawback to the book is the occasional awkward wording that occurs in the translation and makes rapid reading hard. Meaning is never obscured but this, eomb i n d with the detailed discussions and sonlo unfamiliar terminology may make i t difficult t o obtain information from the book quickly and efficiently. This is a minor flaw however, and the translator's contributions add significantly to the hook's usefulness. Research in fuel-rich flames, chemiluminescent excitation, and atomic absorption has progressed rapidly since the hook was written but, thanks t o the translator, much of i t is made available. As a. reference book this is superior t o Dean's "Flame Photometry," dthougb i t is not as concise or redable, and i t lacks the convenient summary of experimental conditions, interferences and applications given for each element by Dean. However, ita completeness and particularly the critical comparisons and evalnat,ions made by Herrmann and Alkemde throughout make their book a very valuable addition to any chemistry library. ALLENC. WEST Williams CoUege Williamtoum, Massachusetts

X-Ray Diffraction in Crystals, Imperfeef Cryrfalr, and Amorphous Bodies

Translated by Paul Lmrain, University of Montred, and Dnrothee Sainte-Marie Lorrain. W. H. Freeman and Company, San Franciso, 1963. x 378 pp. Figs. and tables. 16 X 24 cm. $11. A. Guinier, University of Paris.

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Perhaps the first point t o make about this book is that it is not, and is not intended t o be, an introductory text in X-ray crystallography; there is no discussion of

(Continued on page A388)

BOOK REVIEWS apparatus; the problem of crystal structure determination ie not considered. This translation is a revised version of the laat part only of Guinier'e "ThBorie et Technique de la Radiocristallographie," and as such its coverage is not compr* hensive nor is its level elementary by American college etandards. The small print part of its title, "In Crystals, Imperfect Cryat,als, and Amorphous Bodies" ie helpful in indicating the material covered. A well-orgrtnieed, epeoial, introductory rhapter provides a point of entry, but a knowledge of elementary X-ray crystallography (such aa provided in Guinier's 'X-Ray Crystallographic Technology") is assumed. Chapter 2 develops the general theory of X-ray diffraction for an arbitrary structure and is followed hy applications and exteneione of the theory to amorphous substances: gases, liquids, and vitreous solids (28 pages); crystals (38 pages); very small crystals (30 pages); and inperfect crystals (four chapters, 168 pages). The find chapter (32 pages) is on small angle scattering, in itself the eubject of a monograph by the same author (with Fournet). The book is authoritative, and, considering its compact size, covers a lot of ground. Economy in space is effected, in part, by succinct mathematical expreaeiou including widespread use of vector methods in real and reciprocal space, as might be expected in this field, and of Fourier transforms. (There is a useful appendix on the Fourier transformation,) The author still h d s time to be helpful by calling attention to limitations in the applicability of results and in pointing out and resolving seemingly paradoxical situstione and other difficulties. The printing haa obviously been designed with the intention of revealing rather than hiding the organization of the mat,erial. Italics are used in the running text in such a way as to identify the subject matter as well as to provide emphasis. Conclusions are drawn in summary form a t strategic places. By and large the devices used to help make the book readable and understandable are successful. Occasional errors are, of course, to be found, as the right author to the wrong reference (page 118). The usage of some words will seem a little strange to some, though not inmrrect, such aa "punctual" atoms rather than "paint" atoms, "contrary" for "unlike," and "inversely" where Americans are likely to use "conversely." I t should he stated, however, that the translation is quite readable and in general does not cdl attention to itself. This book cert,ainly belongs in science libraries and will undoubtedly be a eeneible peraanal investment for many phyaicists and chemists and some biologists. It is well worth considering aa a text, tbough I expect that existing courses for which it might be used are more likely to be found in phyaics departments than in chemistry departmenta. The topics emphasized in this hook are not common strong points in books available in English. (Crmtinued o n page A3921

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Chemical Education

BOOK REVIEWS Although the copyright date of t,he second French edition is 1956, this t,ranslation, by virtue of revisions which ineorporate references as recent as 1962, does not suffer from the common failing of being out of date at the time of printing.

The Art and Science of Growing Crystals

Edited by J. J. Gilman, Brown University, Providence, Rhode Island. John Wiley and Sons, Inc., New York, 1963. ix 493 pp. Figs. and tables. 18.5 X 26.5 cm. $20.

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Crystal growth by its nature is a difficult subject to treat in tLn orderly fashion. I t has a firm foundation in many areas of science. Yet it can also be considered an art, since it often depends on knowing or discovering the "right" recipe"rightU in the sense that it works. Both the title and the arrangement of this book recognize and maintain the balance between art and science. The book divides crystal growth into four areas covering vapor growth, preeipitation from liquids, solidification, and recryatdlllieation. Each section hegins with a theoretical discussion of the important parameters and peculiarities of the area by an authority in the field. This is followed by from one to six chaptern dealing with specific substances by soientists active in crystal growth. In the section on solidification, for instance, the general principles of growth from the melt are very well summarized by W. A. Tiller. Growth of low melting point elements which can he contzined in crucibles (including a brief list of conditions for various elements with cautionary notes) is treated by A. J. Goss. Growth of higher melting elements, generally requiring induction or electron bombardment heating is discussed by H. W. Schadler. Dr. Schadler also presents useful experimental details and a summary table of important cryatals grown to date. W. D. Lawaon and S. Nielsen discuss the particular problems that arise in growth of semiconducting compounds, especially the problems connected with maintaming stoichiometry when the vapor pressures of the reacting elements difier greatly. L. R. Weisberg gives more specific details on the growth of the 111-V semiconducting compounds. W. H. Bmer and W. G. Field heve contributed a section on both the classical flame Verneuil and the newer plasma Verneuil erystd ggrwth methods. Although solidification is the longest section in the hook, covering as it does the section of the field in which the most advances have been d e in the "semiconductor decade," the other sections are equally thorough. We see three classes of technical books published these days. Books which puhlish papers presented at a symposium (Continued on page A394)

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1 Chemical Education