The Dictionary of Inorganic Compounds is a continually updated information system on all the most important inorganic chemical substances. Each year a supplement to the main work is issued which brings the whole publication completely up to date. The first supplement lists approximately 1700 entries including both new compounds and new data on compounds already listed in the main work, with literature coverage up to mid 1992. Thus, the complete set of the dictionary is extended to approximately 42,000 compounds in 21,700 entries. Coverage of co-ordination compounds, laboratory chemicals such as solvents and reagents, bio-inorganic compounds and other compounds of particular physical, chemical, structural or biological interest is increased. Each supplement contains name, molecular formula, commonly occurring structural types and CAS Registry Number indexes, as in the main work. The indexes in the second and subsequent Supplements will be cumulative, allowing access to the entries in all the supplements from just the indexes in the latest one.