Acta Cryst. (1993). B49, 576-578

Crystallography in modern chemistry. A resource book of crystal structures

By Thomas C. W. Mak and Gong-Du Zhou

Pp. xiii + 1323. New York: John Wiley, 1992
Price $136.00. ISBN 0-471-54702-6

This book is based on lectures of the authors at the Chinese University of Hong Kong, the University of Western Ontario and Peking University over the past 25 years. It is a tribute to the richness of structural data obtained by X-ray crystallographic studies. The first 20 pages consist of a historical review of crystal structure determinations. Then follow details of structure determinations and discussions of their significance for 27 `fundamental structures', many inorganic structures (of which 43 are compounds of main-group elements and 23 involve compounds of transition elements), 23 organic compounds including vitamin B₁₂ coenzyme and valinomycin, together with 16 organometallic compounds and nine inclusion compounds. These fill nearly 1300 pages. Because the authors provide space groups, unit-cell dimensions and atomic coordinates for approximately 140 crystal structures, together with detailed commentary, conformational descriptions, diagrams and references, the reader may examine the structures in the most comfortable manner, either on a graphics terminal or from the book.

So much for the statistics. This book is a gem of a reference book on structural chemistry, useful for anyone who wishes to learn about the subject. It is like an annotated selection from scientific journals since the science of crystal structure analysis started. It is difficult to give a detailed analysis of such a hefty book, so I have selected a few descriptions that I personally found interesting in order to give readers an overall flavor of the book. There is no other volume that I know of that covers such a wide range of structures together with so much discussion.

Of current interest is the section on buckminsterfullerene and the quest for all-carbon molecules. The descriptions of the crystal structures of benzene and hexamethylbenzene contain a discussion of disordered Kekule-type structures (two D_3h models), and the limitations of X-ray studies in resolving this problem, noting that spectroscopic studies favor a D_6h structure. Cyclooctatetraene and its valence isomers, its benzannelated derivatives and its silver adducts are also described. The description of the crystal structures of the allotropes of boron includes some elegant diagrams of the icosahedral structures found in the various forms. This is followed by information on borides and the structures of the boron hydrides - also derived from icosahedral structures.

General descriptions of structures each highlight some chemical principles. Copper sulfate, the first crystal studied by X-ray diffraction, has a crystal structure that illustrates many points. Neutron-diffraction data give good H-atom coordinates and show the increased H-O-H angle of water on coordination to the copper ion. The Jahn-Teller effect has been studied by charge density studies in CuSO₄.5H₂O and compared to that in isomorphous CrSO₄.5H₂O. The cube-shaped iron-sulfur tetranuclear clusters contain some fascinating chemistry, demonstrated by a variation in Fe-S distances along edges in one direction of the cube. This is described in the context of the various enzymes that contain this cluster, and is interesting with respect to the structure of nitrogenase just reported (since the book was published) and containing an Fe-Mo cluster.

Several examples of crystal structures that lead to descriptions of hydrogen bonding are described. Hydrochloric acid dihydrate, which is H₅O₂⁺.Cl^-, contains very short hydrogen bonds (2.4 Å). The description of hydrogen bonds that follows at this point lists many compounds containing such an H₅O₂⁺ ion, and the analogous protonated water structures found in other acid hydrates. Hydrogen peroxide and its torsion angles are described in the crystal and in the gas phase, together with the sensitivity of the dihedral angle to the surroundings in the crystal.

Perdeutero-alpha-glycylglycine provides an excellent introduction to peptide stereochemistry both with respect to protein structure (alpha-helices and beta-sheets) and the conformations of cyclic polypeptides. The description ends with details of the three-dimensional structures of hemoglobin and insulin.

The absolute configurations of crystal structures are also described. Potassium dihydrogen isocitrate provides a forum for discussion of absolute configuration, the measurement of Friedel pairs, and details of the method of determining absolute configuration. For alpha-quartz, the authors provide a description of its absolute configuration, and of deformation density studies leading to the determinations of atomic charges. I was sorry that the authors did not display a crystal morphology of alpha-quartz with hemihedral faces, the absolute structure and the sense of rotation of plane-polarized light for one of the two possible forms.

Several organometallic compounds of interest are included in this volume. Grignard's reagent (ethylmagnesium bromide), the Mg-C bond and the structures of other alkyl magnesium complexes are described. There follows a discussion of the crystal structure of triethylaluminium and the Al-C bond. In Zeise's salt K[H₂C=CH₂)PtCl₃].H₂O, the platinum is 2.02 Å from the carbon-carbon double bond and the hydrogen atoms are bent away from the metal. Dimanganese decacarbonyl, Mn₂(CO)₁₀, has an Mn-Mn bond and has been the subject of deformation density studies. The nature of bonding in such compounds is discussed in detail. This leads on to well referenced information on the cluster structures of a variety of metals. The crystal structure of ferrocene, a molecule with two five-membered rings sandwiching an iron atom, is complicated by disorder problems. A detailed molecular orbital analysis follows descriptions of this type of structure. Cobaloximes - cobalt derivatives of dimethylglyoxime that bind an aromatic base and alkyl groups in axial positions - are of interest with respect to the stability and reactivity of the Co-C bond. In the crystalline state they can undergo a photochemical reaction leading to racemization if there is room in the crystal for the necessary movement of functional groups. The electronic effects of the axial ligands on each other are also of interest. These complexes are used as models for the action of vitamin B₁₂.

Molecular packing is well illustrated. Phase diagrams and crystal structures are presented for eight or more forms of normal ice and its high-pressure polymorphs. The prostaglandins have long alkyl side chains and their various conformations and the mode of packing of alkanes are well described. The crystal structure of methyl p-bromocinnamate provides an example of another compound that undergoes a solid-state reaction. In this structure the distance between C=C bonds in adjacent molecules in the crystal structure is 4.1 Å. A photochemical reaction leads to cyclization to a truxillic acid derivative.

There is a most interesting section on dehydrated zeolite 4A (Linde molecular sieve type 4A), a structure determined in 1977, leading into a description of framework structures and polyhedral cages in zeolites. Inclusion compounds, such as the cyclodextrins, are discussed because they provide a framework not only for molecular binding but also for reactions (cyclodextrin-based artificial enzymes).

The aim of the authors is to teach structural chemistry, so that the book should appeal to both students and teachers. The compounds chosen for description were selected with care to illustrate a point in chemistry or stereochemistry. The choices are excellent. The authors have not always chosen standard examples, but have selected those that illustrate some good chemical principles. They show a deep appreciation of the overall literature in this field. With this book a teacher can introduce the student to the entire field of structural chemistry. The various publishers who have allowed their figures to be published are to be complimented. The stereodiagrams are very helpful in providing three-dimensional views of the crystal structures and the overall choice of illustrations is very good.

This is a book that should be lying in every chemical and biochemical laboratory. It is excellent to refer to for lecturing and illustrates well the power of structural studies with much useful data, diagrams and commentaries. The high price is unfortunate as it puts the book out of reach of a student audience and may deter scientists who would benefit from owning this splendid work from acquiring it for their personal libraries.

Jenny P. Glusker

The Institute for Cancer Research
Fox Chase Cancer Center
7701 Burholme Avenue
Philadelphia, PA 19111
USA

Acta Cryst. (1997). B53, 738

Pp. xiii + 1323. Chichester: John Wiley & Sons, Ltd, 1997
Price £55.00, US $76.95 (paperback). ISBN 0-471-18438-1

This is a paperback reprint of the original 1992 publication of this book, reviewed above in this journal by J. P. Glusker [Acta Cryst. (1993), B49, 576-578]. It meets, at least in part, Dr Glusker's criticism that the high price of the original `puts the book out of reach of a student audience and may deter scientists who would benefit from owning this splendid work from acquiring it for their personal libraries'.

Copyright © 1997 International Union of Crystallography