Crystal engineering : the design of organic solids by G. R. Desiraju

In his preface to this book, Professor Desiraju notes the lack of interaction between the three groups of workers at which he aims the volume: organic chemists and materials scientists involved in purposeful crystal design, theoreticians interested in intermolecular interactions and crystallographers searching for patterns in crystal structures. He attempts to bridge the gaps between these groups by pooling research results in all three areas to draw conclusions as to the nature of crystal structure determining forces and their use in 'crystal engineering', a term he credits G. M. J. Schmidt with coining. The book opens with a chapter which neatly sets out the author's aims and explains the motives behind the discipline of crystal structure design. The emphasis here is very much on topochemical solid-state reactions, although some mention is made of non-linear optics and molecular conductivity. Crystal morphology and the reasoning behind possible needs to influence it are not covered here sadly, although brief reference is made in later chapters to the work of Lahav and Leiserowitz in this area. The book then continues with largely non-mathematical descriptions of the computational and statistical methods of crystal structure prediction. A fairly lengthy description of the Cambridge Structural Database (up to version 3, January 1989 update) is perhaps unavoidable here, but dates the book. Chapters 4 to 7 consist of examples of structures illustrating the effect of isotropic van der Waals and the more directionally specific hetero-atom interactions in determining crystal structures. The examples are well chosen and illustrated, with a variety of diagrams and stereo drawings of structures that bring the author's points over clearly. The importance of the hydrogen bond is strongly emphasized; the chapter dealing with it is the longest in the bookl Chapters 8 and 9 cover the design of crystal structures for specific purposes, such as non-centrosymmetric crystals for non-linear optics, and tailored clathrates. A particularly interesting example here, and in the earlier chapter about sulfur-sulfur interactions, is that of the role of such interactions in determining the stack and sheet structures of the so-called organic metals. Polymorphism, described as 'the Nemesis of crystal design?', is discussed in the final main chapter, which is disappointingly short at only 16 pages. This seems to underestimate the importance of the phenomenon, although the author has clearly resisted the temptation to sweep it under the carpet entirely. Polymorphism, while adding to our understanding of the balance between intermolecular interactions, makes crystal design very much an imprecise discipline. In his final conclusions, the author comments that the relationships between crystal structure and properties such as solvation, ease of growth and morphological quality are largely uncharted waters. Much research effort is currently being employed in these areas, so perhaps, in ten years time, the rather vague conclusion that crystal engineering is still something of a black art may be replaced by a more firm strategem for the discipline. However, Professor Desiraju has succeeded in pulling together evidence from various different fields to aid the would-be crystal engineer in a useful text that builds on the earlier works of Kitaigorodski. STEPHEN J. MAGINN