Crystallography : A Very Short Introduction . By A

Abstract

This book is a new volume published as part of the Oxford ‘Very Short Introduction’ series, which aims to give easy access to various subjects. After a very general preface, which introduces the role of crystallography in science, this 168-page book is divided into six chapters. Chapter 1 entitled ‘A long history’ is a very well documented chapter and may be the best chapter of the book; it clearly defines most concepts and all the steps in building the science of crystallography from Kepler’s 1611 pamphlet to modern X-ray crystallography: symmetry, X-ray diffraction, mineral, organic and protein structures. I just regret that the author gives the example of the quartz prism to highlight sixfold (Fig. 3) symmetry: it is not false but it may cause the reader to think that quartz crystallizes in a hexagonal point group (unless he describes the high-temperature phase!). This historical chapter is also interesting because it briefly describes the life of most of the important pioneers of the field in relation to their research: for example, the author relates the strong opposition to W. L. Bragg’s model of the NaCl structure (1915) and to the ionic bonding (p. 19) by reproducing an amazing letter published in Nature in 1927. Chapter 2 is devoted to symmetry. It is a very short chapter, well written and without any mathematics; symmetry concepts, point groups and Bravais lattices are clearly introduced. Crystal structure and space groups are described using the convolution tool. However, it is surprising that the author never cites the Hermann–Mauguin space-group symbol which is used in Volume A of International Tables for Crystallography; he seems to prefer the term ‘International Notation’, but the Schoenflies symbol is also recognized as an international notation. Chapter 3 describes the crystal-structure types from close packing to protein structures. The paragraph entitled ‘Close packing’ in fact describes the most important inorganic structure types and some of their symmetry-related properties like piezoelectricity. I liked the discussion about the Bravais lattices of simple crystal structures. Polymorphism is introduced for the element carbon but is not discussed in the ‘Organic structures’ paragraph, which is a real pity: this paragraph is really too short and not at all up to date. It does not describe the key role of polymorphism in the pharmaceutical industry, in material science and in crystal-growth research; even the new, important concepts of crystal engineering and co-crystals are not discussed. As the book describes the physical properties of some minerals, a quick survey of the physical properties of the molecular materials (magnetism, optics, dielectrics etc.) would have been very welcome. This remark holds also for the paragraph ‘Crystal growth’, which is devoted to mineral materials and proteins. Biological molecules (proteins, virus, DNA) are described in more detail. Chapters 4, 5 and 6 describe diffraction methods using X-rays (conventional tube, synchrotron and free-electron laser), neutrons and electrons. Chapter 4 introduces the diffraction concepts using a purely geometrical approach: first, the reciprocal lattice is defined and abruptly used to explain the Ewald sphere concept knowing the Bragg law (introduced much earlier, p. 15). Then the diffraction pattern is explained using the convolution theorem, but nothing is written about the interaction between matter and X-rays, neutrons or electrons. I think that it is extremely important to show the reader that X-rays, neutrons or electrons are, respectively, scattered by the electron density, the nuclear and magnetic density or the electrostatic potential of the atoms [or generated by ISSN 2053-2733

Cite this paper

@inproceedings{Lecomte2017CrystallographyA, title={Crystallography : A Very Short Introduction . By A}, author={Claude Lecomte}, year={2017} }