Sodium azide reacts with RuH2 ( dmpe )2 (1a) ( dmpe = 1,2-bis( dimethylphosphino )ethane) in methanol solution to form RuH (N3)( dmpe )2 (2a), and reacts with RuCl2( depe )2 (3b) ( depe = 1,2-bis( diethylphosphino )ethane) to form the bis ( azide ) complex Ru (N3)2( depe )2 (4b). The crystal structures of Ru ( Cl )2( depe )2 (3b) and Ru (N3)2( depe )2 (4b) have been determined and indicate that the chloro groups in (3b) and the azido groups in (4b) are trans across the metal centre.