Specialist Periodical Reports provide systematic and detailed review coverage of progress in the major areas of chemical research. Written by experts in their specialist fields the series creates a unique service for the active research chemist, supplying regular critical in-depth accounts of progress in particular areas of chemistry. For over 80 years the Royal Society of Chemistry and its predecessor, the Chemical Society, have been publishing reports charting developments in chemistry, which originally took the form of Annual Reports. However, by 1967 the whole spectrum of chemistry could no longer be contained within one volume and the series Specialist Periodical Reports was born. The Annual Reports themselves still existed but were divided into two, and subsequently three, volumes covering Inorganic, Organic and Physical Chemistry. For more general coverage of the highlights in chemistry they remain a 'must'. Since that time the SPR series has altered according to the fluctuating degree of activity in various fields of chemistry. Some titles have remained unchanged, while others have altered their emphasis along with their titles; some have been combined under a new name whereas others have had to be discontinued. The current list of Specialist Periodical Reports can be seen on the inside flap of this volume.
Molecular Structure by Diffraction Methods Volume 4
A Review of the Literature Published between April 1974 and September 1975
By G. A. Sim, L. E. SuttonThe Royal Society of Chemistry
Copyright © 1976 The Chemical Society
All rights reserved.
ISBN: 978-0-85186-537-9Contents
Part I Electron Diffraction, 1,
Introduction to Part I By L. E. Sutton,
Chapter 1 Electron Diffraction Determinations of Gas-phase Molecular Structures By D. W. H. Rankin, 5,
Chapter 2 Developments in the Apparatus Used in Europe, including U.S.S.R., for Studies of Electron Diffraction in Vapours By H. Oberhammer, 24,
Chapter 3 Large-amplitude Vibrations: Their Study by Electron Diffraction and Spectroscopic Techniques By A. G. Robiette, 45,
Introduction to Parts II and III By G. A. Sim, 62,
Part II Neutron Diffraction By J. C. Speakman, 63,
1 Introduction, 65,
2 Hydrogen Bonding and Related Topics, 65,
3 Organic Compounds, 72,
4 Inorganic and Organometallic Compounds, 73,
5 Miscellaneous Topics, 77,
Part III X-Ray Diffraction, 81,
Chapter 1 Aromatic and Analogous Unsaturated Molecules By A. F. Cameron, 83,
Chapter 2 Molecular Complexes, Hydrogen-bonded Systems, and other Intermolecular Interactions By A. F. Cameron, 95,
Chapter 3 Non-aromatic Hydrocarbons and Analogous Compounds By A. F. Cameron, 104,
Chapter 4 Natural Products and Related Compounds By G. A. Sim, 134,
Chapter 5 The Structure of Globular Proteins and Nucleic Acids By T. L. Blundell, 183,
Chapter 6 Titanium, Zirconium, and Hafnium By M. B. Hursthouse, 195,
Chapter 7 Vanadium, Niobium, and Tantalum By M. B. Hursthouse, 200,
Chapter 8 Chromium, Molybdenum, and Tungsten By Lj. Manojlovic-Muir, 207,
Chapter 9 Manganese, Technetium, and Rhenium By Lj. Manojlovic-Muir, 229,
Chapter 10 Iron, Ruthenium, and Osmium By W. S. McDonald, 242,
Chapter 11 Cobalt, Rhodium, and Iridium By Lj. Manojlovic-Muir and K. W. Muir, 264,
Chapter 12 Nickel, Palladium, and Platinum By K. W. Muir, 292,
Chapter 13 Copper, Silver, and Gold By W. S. McDonald, 319,
Chapter 14 Scandium, Yttrium, Lanthanides, and Actinides By M. B. Hursthouse, 346,
Chapter 15 Zinc, Cadmium and Mercury By M. B. Hursthouse, 355,
Chapter 16 Boron, Aluminium, Gallium, Indium, and Thallium By M. B. Hursthouse, 365,
Chapter 17 Carbon, Silicon, Germanium, Tin, and Lead By M. B. Hursthouse, 379,
Chapter 18 Nitrogen, Phosphorus, Arsenic, Antimony, and Bismuth By M. B. Hursthouse, 393,
Chapter 19 Oxygen, Sulphur, Selenium, and Tellurium By M. B. Hursthouse, 406,
Chapter 20 The Halogens and the Noble Gases By M. B. Hursthouse, 403,
Chapter 21 Lithium, Beryllium, Magnesium, and the Alkali-metal and Alkaline-earth Elements By M. B. Hursthouse, 415,
Author Index, 421,
CHAPTER 1
Part I
ELECTRON DIFFRACTION
Introduction to Part I: Electron Diffraction
BY L. E. SUTTON
In this Volume there are three Chapters relating to electron diffraction studies of molecular structure.
The first is the usual comprehensive survey of recent work, again written by Dr D. W. H. Rankin, covering papers published up to the end of August 1975. Dr Rankin had considerable difficulty in obtaining copies of certain journals, because libraries are cutting down their subscription lists; so the need for such a review is evidently becoming even greater. He remarks that although the fall in output of papers continues, the quality has advanced markedly. There are numerous studies of structural detail in large and complex molecules, often by the now well-established techniques for combining diffraction and spectroscopic data. There are also measurements of notable accuracy on small molecules. Of unique interest are the investigations on substances that are very difficult to volatilize, which have been the special province of Russian workers.
The mass of data for bond lengths is now enormous: one can say, in current parlance, that there is a data mountain. This means that it is becoming something of an embarrassment. Our contributors have noted the relevance of many of the observations that they have reported to the concepts which have been used in rationalizing bond lengths and their variations, such as covalent radius, bond order, hybridization, bond polarity, co-ordination number, and van der Waals radii or potential functions between non-bonded atoms; but they have only been able to do this in passing. There is no lack of bases for rationalization; there may be a surfeit. A fresh, systematic, and critical review of their adequacy, usefulness, and reliability now seems due. This Senior Reporter will not be volunteering for the task,
Dr H. Oberhammer has contributed a second Chapter on Apparatus Developments, to complete the review begun in the previous Volume by R. L. Hilderbrandt. This one deals with advances made in Europe including the U.S.S.R. In view of the interest of the high-temperature work it is appropriate and timely that Dr Oberhammer should be able to include an authoritative description of the equipment used for it. He also describes the first commercially-built camera.
The third Chapter, by Dr A. G. Robiette, is on the study of large-amplitude vibrations in molecules. Investigators are increasingly concerned to elucidate the 'molecular mechanics'. This includes establishing, and if possible explaining, the potential energy functions that govern the relative motions of atoms in a molecule. These functions can become highly anharmonic and may have more than one minimum, It is with the subtleties of these difficult but very interesting problems that Dr Robiette is especially concerned.
The volume in the Landolt-Bornstein series of Tables, on interatomic distances, which was mentioned in the Introduction to Volume 1, is due to appear in September or October of this year (1976). It will list data for molecules, obtained from vapour-phase measurements by spectroscopy, electron diffraction, or the two combined; but it will not include data for diatomic molecules. The deadline for publications to be included was June 1974. Its appearance will be most welcome; and all concerned with its production are to be thanked and congratulated on completing their task.
It remains for me to thank the contributors to this Volume for their promptness and their general helpfulness, which I do with great pleasure.
1 Electron Diffraction Determination of Gas-phase Molecular Structures
BY D. W. H. RANKIN
1 Introduction
During the year from September 1974 to August 1975, about 85 papers were published reporting the results of structure determinations by electron diffraction. Thus the trend of a decreasing volume of output, noted a year ago, has continued. A crude extrapolation suggests that the last electron diffraction paper of all time will appear in 1984, and this series of chapters of results will end with Volume 13!
This decline in quantity has fortunately been accompanied by a marked advance in quality. To an ever-increasing extent, information derived from electron diffraction experiments has been combined with data from other sources, to provide solutions to problems that proved to be insoluble using one technique in isolation. At one extreme of scale, very small molecules are being studied with great care and precision, using microwave and diffraction data. By such means it has been possible to determine the effect of substituting 37Cl for 35Clo n the...
