236 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS INTERPRETATION OF ORGANIC SPECTRA. Editor: D. W. Mathieson. Pp. ix q- 179 q- Ill. (1965). Academic Press, London and New York. 42s. This is a pragmatic book, intended to give practice in the interpretation of three important fields of diagnostic organic spectrometry. As an editorial principle, the sections are self-contained- up to ten illustrative spectra are discussed in detail but deliberately making reference to little or no ancillary chemical, physical or other spectroscopic data. This unnatural isolation helps to focus attention on both the strength and the weaknesses of nmr, ir and mass spectrometry as diagnostic tools. Moreover the authors assume prior knowledge not only of the principles, which in fact most empirical texts do, but also experimental procedures and to a certain extent terminology. On reflection one must agree that this is fair since it is the newly practising spectroscopist who mainly will wish to use this work. It may be noted that Bellamy (1), which is one of the best known standard texts on the inter- pretation of ir spectra, adopts a similar embargo however Scott (2) includes a most useful general introduction on the electronic significance of uv spectroscopic measure- ments. It is arguable just how much background material an author should include to widen the scope and potential readership but at the same time risk unduly increasing the size (and price) of the book. The first part is allegedly concerned with nmr but in fact deals entirely with proton magnetic resonance spectra- which is what most users will want. The so- called "Introduction" is no exception to the editorial rule, the reader is indulged to the extent that there is a brief and simple example of splitting rules for adjacent proton interaction (in the ethoxy group) but he is then unsettled by being assured that in practice the idealized first order coupling pattern is rarely met. In this respect the introductory discussion in the nmr chapter in Schwarz (3) is to be preferred (but even those explanations are sometimes a little disjointed). The main section comprises a series of ten examples of pmr spectra which are discussed minutely and are fascinating to work through, although the occasional catagoric statement, apparently made ex cathedra, is not always rationalizable on closer study. Misprints are few but a mistake in the molecular formula that is given with Example 10 may, temporarily, be most misleading. Judging by the difficulty which your reviewer encountered in seeking to solve the six supplementary unworked examples, a single reading of this book, without reference elsewhere, is not sufficient to acquire pro- ficiency in the interpretation of pmr spectra- but it certainly gives one a very fair initiation into its problems. With regard to the display of ir spectra, inevitably the conflict of different conventions arises. Thus both wavelength and wave-number scales are engraved on every spectrum but some readers will be irritated to find that many of the traces have the absorbance increasing from top to bottom of the charts. All the bands in these spectra are annotated and discussed in reciprocal cm units, but wavelengths can easily be read off from the generally linear upper abscissa. Nevertheless the casual reader must be alert for changes in the scanning speed at certain frequencies. Following the editorial principle, previous acquaintance with the nature of skeletal (1) Bellamy, L. J. Infra-red spectra of complex molecules, 2nd. edn. 1958. (2) J. ].õ 480 (1965). (3) Schwarz, J. C. P., Physical methods in organic chemistry, 1964.

BOOK REVIEWS 237 vibrational (and rotational) deformations is assumed and the text comprises an empirical discussion of worked examples. Although the spectra are examined in isolation, the author rightly emphasizes the importance of supplementary physical data in narrowing the field of possible structures and that it is the exception rather than the rule to effect a complete structural identification from the ir spectrum alone. The series of examples comprise hydrocarbons of increasing complexity and unsatura- tion, followed by the introduction of various functional groups natural extracts as well as specific compounds are considered. Compared with the pmr section, there is rather more discussion in the form of interesting extensions to general cases from the particular examples given. Instead of correlation tables for functional groups in various environments, there is constant reference to Bellamy and to the other well used standard work, Jones and Sandorfy (4). The section on mass spectroscopy begins with some useful empirical tips for the general examination of low resolution spectra, including the use of isotopic abundance ratios particularly for identifying parent peaks, the stability of various systems reflected in the strength of their parent ions, the unique situation of mass sums for odd numbers of nitrogen atoms and the so-called "z number" classification for codifytrig the degree of unsaturation of hydrocarbons and- by suitable correction- other functional substitution. Examples are developed from the logical consideration of the cracking patterns of relatively simple molecules, noting particularly the bonds at which cleavage preferentially occurs for different functions and the particular mass ratios favoured thereby, which being independent of chain length are diagnostic for that function. References are given sequentially to authors who have specifically reviewed the various functions and to the American Petroleum Institute collection of mass spectra for the unique allocation of a cracking pattern to a particular hydro- carbon. The impression given is that the interpretation of mass spectra is a notably more intuitive exercise than the consideration of pmr or ir spectra. The use of a computer would seem a considerable advantage in rejecting numerous competing structures, particularly for the polyfunctional compounds of higher molecular weight reference to such a sophisticated approach for high resolution mass spectroscopy was made when reviewing (5) Biemann's contribution to the 3rd IUPAC symposium on the chemistry of natural products. It should be emphasized, however, that the present book is concerned with low resolution, single focussing instruments the very expensive double focussing machines are still sufficiently rare not to warrant consideration in a manual of interpretation for the majority of practising organic chemists. There is therefore no distinction between the masses of CH4, IqH2 or O, except that one may recognize the proportion of carbon atoms from the intensity of the "shadows" due to •aC isotope. The pmr and ir sections of this book are based upon a practical course presented by the authors at the very successful summer school in spectroscopy organized by the R.I.C. in 1964. The ir section is not by itself usable as a source book but is essentially a tutorial work. The previous section however sets out- and largely succeeds - in doing both for pmr spectra. The account of low resolution mass spectra has been prepared by two well-known practitioners. Altogether Dr. Mathieson has supplied a very stimulating text book for the newly practising spectroscopist. G. F. PHILLIPS. (4) Jones, R. N. & Sandorfy, C. Vol. IX of Technique of organic chemistry, (1956). (5) J. 15 418 (1965).