The trinuclear osmium complex, Os3N7O9H21

The initial product of the interaction of osmium (VIII) oxide and ammonia, OsO4·NH3, is shown to undergo dehydration to nitrido-osmic-(VIII) acid which in turn is converted to the trinuclear species Os3N7O9H21 or its partially dehydrated analogue, Os3N7O7H17. Infra-red spectral, thermogravimetric analysis, and other data are used to elucidate the structure of Os3N7O9H21, including its conversion to a related complex Os3N5O5H7 by dehydration and deammoniation.