The hydrate, with a varying proportion of water of crystallization, often approximating to a trihydrate, is a commonly used starting material in ruthenium chemistry.

In the original synthesis, the chlorination was conducted in the presence of carbon monoxide, the product being carried by the gas stream and crystallising upon cooling.

[5] The dark brown metastable β-form crystallizes in a hexagonal cell; this form consists of infinite chains of face-sharing octahedra with Ru-Ru contacts of 283 pm, similar to the structure of zirconium trichloride.

Ryōji Noyori was awarded the Nobel Prize in Chemistry in 2001 for the development of practical asymmetric hydrogenation catalysts based on ruthenium.

Robert H. Grubbs was awarded the Nobel Prize in Chemistry in 2005 for the development of practical alkene metathesis catalysts based on ruthenium alkylidene derivatives.

[18] In contrast, iron chlorides do not react with CO. CO reduces the red-brown trichloride to yellowish Ru(II) species.