Ruthenium pentacarbonyl is the ruthenium compound with the formula Ru(CO)<sub>5</sub>. It is a colorless, light-sensitive liquid that readily decarbonylates upon standing at room temperature. It is of academic interest as an intermediate for the synthesis of metal carbonyl complexes.
Ru(CO)<sub>5</sub> was originally prepared by carbonylation of ruthenium salts in the presence of a reducing agent. A more recent preparation involves photolysis of triruthenium dodecacarbonyl in the presence of carbon monoxide:
It is characterized by two intense ý<sub>CO</sub> bands in the IR spectrum at 2038 and 2003 cm<sup>âÂÂ1</sup> (hexane solution).
Whereas Fe(CO)<sub>5</sub> is completely robust at room temperature, samples of Ru(CO)<sub>5</sub> are typically reddish owing to contamination by Ru<sub>3</sub>(CO)<sub>12</sub>. The conversion is rapid in solution. Os(CO)<sub>5</sub> requires heating to 80 ðC to effect conversion to triosmium dodecacarbonyl.