This Dictionary provides an explanation of the main ideas of and concepts central to chemistry. Each entry in this A-Z resource begins with a clear, one-sentence definition that explains why the term is important. These sentences are followed by a fuller explanation and, where appropriate, examples, diagrams, tables and equations. Key terms such as inorganic chemistry, organic chemistry, physical chemistry, the chemical industry, and qualitative analysis tell the user about the main features of important aspects of chemistry, with cross-references leading to related terms in each field. Other entries give a historical perspective, showing in outline how important themes of chemistry have developed.