Physical properties of bis(2,4-dimethylpentadienyl)ruthenium [Ru(DMPD)(2)] were compared with those of (2,4-dimethylpentadienyl)(ethylcyclopentadienyl)ruthenium [Ru(DMPD)(EtCp)]. Ru(DMPD)(2) showed a high vapor pressure of 13.3 Pa at 82 degrees C and a decomposition temperature of 210 degrees C, which is 60 degrees C lower than that of Ru(DMPD)(EtCp). Metallic Ru film was deposited on oxidized Si(100) from a Ru(DMPD)(2)-O-2 system in a deposition temperature range from 220 to 400 degrees C by metallorganic chemical vapor deposition (MOCVD), and crystalline metallic Ru films with smooth surfaces were deposited down to 220 degrees C for the first time from a Ru(DMPD)(2)-O-2 system. (c) 2007 The Electrochemical Society.