The Basics of Crystallography and Diffraction (2nd edn)

Abstract

This revised edition of a book which forms a part of the International Union of Crystallography's series of Texts on Crystallography is some 30% larger than its predecessor, amongst other reasons because of increased coverage of diffraction and the inclusion of a separate chapter on the stereographic projection. Overall Dr Hammond covers the topics one would expect from the title. It is particularly pleasing to see considerable emphasis placed on symmetry, a topic that is fundamental to crystallography but is all too often played down these days in elementary courses because of the demands it makes on students' ability to appreciate matters that are underpinned by rigorous mathematical arguments, even when, as here, the formalities are replaced by persuasive text. Indeed the level of the mathematics in the book has deliberately been kept simple. The expanded chapters on diffraction cover the basic theoretical background for x-ray and electron diffraction, with a brief reference to neutron diffraction, illustrated by reference to a range of experimental methods. Perhaps the selection might have given greater emphasis to counter-diffractometry and computer-based data analysis rather than to photographic methods but the latter are arguably better at illustrating important geometrical aspects of data collection. Each chapter is rounded off with a helpful set of exercises, for which detailed answers are provided at the end of the book.A separate strand that runs throughout the book informs the reader about the history of the subject from its early days to the present, culminating in appendix 3, which presents brief biographies of almost 50 figures influential in the development of crystallography and diffraction, many of whom are remembered daily, without appreciation of their human side, because their names are attached to important parts of the theoretical or practical `apparatus' of the subject. Other appendices contain helpful information about sources of components for crystal model-building and about useful software as well as information on a number of geometrical and mathematical topics.Finally, one name in particular leapt out from the author's acknowledgments: the reviewer too acknowledges with gratitude the guidance of Dr Norman Henry many years ago!In short, this book is an excellent attempt to present in an interesting yet simple way a subject that many students find daunting. It well deserves to succeed.John A Leake

Polymer chain/nanocrystal ordering in thin films of regioregular poly(3-hexylthiophene) and blends with a soluble fullerene

“…These results indicate a correlation between the degree of RR and the intensity of the higher order diffraction peaks that relate to higher degrees of crystal and/or chain ordering. 19 In addition, the higher order diffraction peaks, ( 200) and (300), completely disappear for a . 45u irrespective of RR and thermal annealing (these peaks exist for a # 27u for the 95.2% RR P3HT films though the data are not shown here).…”

Single molecule protein stabilisation translates to macromolecular mechanics of a protein network

“…Kiessig fringes are the result of an interference effect due to the scattering from two separated interfaces (where the separation is much larger than the incident wavelength) such that the Bragg condition is satisfied. 66,67 So the emergence of such fringes implies the existence of a repeating length scale of approximately 1000 Å in the system. The lack of definition in these fringes is what leads to the large error in these values but also is indicative that the length scale is not well defined in the system i.e.…”

Pressure‐induced incipient amorphization of α‐quartz and transition to coesite in an eclogite from Antarctica: a first record and some consequences

“…The relationship between the size of crystals and the broadening of the corresponding spots is given by the Scherrer equation: b = k ⁄ (t.cosh), where b is the breadth of the peak at half its maximum intensity, k is the XR wavelength and t is the size (e.g. Hammond, 2004). However, instrumental factors contribute to the broadening and should be subtracted from b (i.e.…”