A grammar based upon a conventional morphemic analysis of Russian will have a rather large inventory of derivational suffixes. A relatively small number of these recur with sufficient generality to acquire lexemic status (i.e., to be what is usually termed “productive”). Names of chemical substances in Russian may likewise be analyzed as combinations of roots or stems with derivational affixes, in particular, suffixes. The number of productive suffixes in the chemical nomenclature is considerably larger than in the general vocabulary. These suffixes derive from adoption into Russian of an international system of chemical nomenclature. A grammar of this system is basically independent of any grammar of Russian. It must, however, be consistently incorporated into the grammar and dictionary which are to serve in a machine translation system for texts in the source language containing chemical names. Grammatical analysis of chemical suffixes and connected study of general Russian derivational suffixes has raised certain practical problems and theoretical questions concerning the nature of derivation. On the practical side, where a complex and highly productive system is involved, effective means of detecting and dealing with homography have required development. Theoretical consideration has been given to the question of grammaticality in chemical names and to problems of sememic analysis and classification of root and stem lexemes into tactic classes on the basis of cooccurrence with derivational suffixes.