Ruthenium compounds

The most prevalent precursor is ruthenium trichloride, a red solid that is poorly defined chemically but versatile synthetically.

[3] Unlike osmium tetroxide, ruthenium tetroxide is less stable, is strong enough as an oxidising agent to oxidise dilute hydrochloric acid and organic solvents like ethanol at room temperature, and is easily reduced to ruthenate (RuO2−4) in aqueous alkaline solutions; it decomposes to form the dioxide above 100 °C.

Like iron, ruthenium does not readily form oxoanions and prefers to achieve high coordination numbers with hydroxide ions instead.

It hydrolyzes violently upon contact with water and easily disproportionates to form a mixture of lower ruthenium fluorides, releasing fluorine gas.

[6] Ruthenium trichloride is a well-known compound, existing in a black α-form and a dark brown β-form: the trihydrate is red.

The colorless liquid ruthenium pentacarbonyl converts in the absence of CO pressure to the dark red solid triruthenium dodecacarbonyl.

Ruthenium trichloride reacts with carbon monoxide to give many derivatives including RuHCl(CO)(PPh3)3 and Ru(CO)2(PPh3)3 (Roper's complex).