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.

[2] Ru(CO)5 was originally prepared by carbonylation of ruthenium salts in the presence of a reducing agent.

[3] A more recent preparation involves photolysis of triruthenium dodecacarbonyl in the presence of carbon monoxide:[2] It is characterized by two intense νCO bands in the IR spectrum at 2038 and 2003 cm−1 (hexane solution).

[2] Whereas Fe(CO)5 is completely robust at room temperature, samples of Ru(CO)5 are typically reddish owing to contamination by Ru3(CO)12.