Gunnar Nordberg
Occurrence and Uses
Ruthenium is found in the minerals osmiridium and laurite, and in platinum ores. It is a rare element comprising about 0.001 ppm of the Earth’s crust.
Ruthenium is used as a substitute for platinum in jewellery. It is utilized as a hardener for pen nibs, electrical contact relays and electrical filaments. Ruthenium is also used in ceramic colours and in electroplating. It acts as a catalyst in the synthesis of long-chain hydrocarbons. In addition, ruthenium has been used recently in treating eye uveal malignant melanomas.
Ruthenium forms useful alloys with platinum, palladium, cobalt, nickel and tungsten for better wear resistance. Ruthenium red (Ru3Cl6H42N4O2) or ruthenium oxychloride ammoniated is used as a microscopy reagent for pectin, gum, animal tissues and bacteria. Ruthenium red is an eye inflammatory agent.
Hazards
Ruthenium tetraoxide is volatile and irritating to the respiratory tract.
Some ruthenium electroplating complexes may be skin and eye irritants, but documentation of this is lacking. Ruthenium radioisotopes, chiefly 103Ru and 106Ru, occur as fission products in the nuclear fuel cycle. Since ruthenium may transform to volatile compounds (it forms numerous nitrogen complexes as noted above), there has been concern about its uptake in the environment. The significance of radio-ruthenium as a potential radiation hazard is still largely unknown.