2 - Physical methods in the characterisation of inorganic substances

Summary

Introduction

This chapter presents a brief survey of the more important physical techniques to which reference will be found in more comprehensive texts. It was noted in Chapter 1 that inorganic chemists have become increasingly preoccupied with physical methods since about 1950, often to the extent that the development of the technique and the underlying theory overshadow the inorganic chemistry. Inorganic chemists have indeed invaded large parts of the territories traditionally associated with physical chemistry. It was pointed out in the Preface that the neglect of factual, descriptive chemistry in contemporary inorganic courses and texts has been a direct consequence of the emphasis placed upon physical and theoretical matters. It is proper, however, that an account of descriptive inorganic chemistry should make some mention of the methods used in determinations of structures etc. A scientist should always be prepared to give a rational and convincing answer to the question: ‘How do you know that?’ In order that the student who asks such a question receives a meaningful reply, it is necessary to have some knowledge of the kind of information conveyed by a given method, its strengths and its limitations.

A great number of physical properties have been used by inorganic chemists, and new physical methods appear regularly, some to join existing methods as indispensable weapons in the arsenal and others to sink into obscurity after a short period of popularity.