The purpose of this book is to help chemists, biochemists and other scientists purify the chemical reagents which they use in their work. Although commercially available laboratory chemicals are usually satisfactory as supplied for some purposes in science and technology, for many applications further purification is essential. Therefore the two main chapters of the book describe processes, taken from the literature, for purifying over 5000 organic, inorganic and organometallic commercially available chemicals. Two further chapters describe the methods and techniques currently used for purification in laboratories. In addition, for dealing with substances not separately listed, a chapter is included setting out methods for purifying specific classes of compounds. Finally, there is a new chapter dealing with biological substances which indicates current methods of purification in this area. This expanded and revised third edition includes several hundred individual compounds not previously covered, and more information is given for most entries, including melting and boiling points, molecular weights, refractive indexes, densities and Chemical Abstracts registry numbers, as well as likely contaminants and storage conditions in some cases. In addition, safety information and hazardous substances are indicated as appropriate. Recent developments in techniques of purification have also been added, including new chromatographic methods and materials.