Ruthenium: reactions of elements
Reaction of ruthenium with air
Ruthenium is largely immune to atmospheric attack. On heating with oxygen, ruthenium metal gives ruthenium (IV) oxide, RuO2.
Ru(s) + O2(g) → RuO2(s)
Normally second and third row d-block elements show similar chemistries, but in this case, osmium (immediately below ruthenium in the periodic table) burns to give osmium (VIII) oxide, OsO4.
Reaction of ruthenium with water
Ruthenium does not react with water under normal conditions.
Reaction of ruthenium with the halogens
Ruthenium reacts with excess of fluorine, F2, to form ruthenium(VI) fluoride, RuF6.
Ru(s) + 3F2(g) → RuF6(s) (dark brown)
Heating ruthenium metal at 330°C with chlorine, Cl2, in the presence of carbon monoxide, CO, produces dark brown ruthenium (III) chloride, RuCl3. Further heating of this material under Cl2 gives a black form of ruthenium (III) chloride.