Iridium - Ir

Elements

Atomic number 77

Atomic mass 192.2 g.mol -1

Density 22.4 g.cm-3 at 20°C

Melting point 2450 °C

Boiling point 4527 °C

Discovered by Smithson Tennant in 1804

Iridium is a hard, brittle, lustrous, dense, transition metal of the platinum family. It is silvery-white and it is notable for being the most corrosion resistant element known. It is unaffected by air, water and acids.

Applications

Nowadays demand for iridium comes mainly from the electronic industry, the automotive industry and from the chemical industry, where it is used to coat the electrodes in the chlor-alkali process, and in catalyst.

Some applications are in pivot bearings and in scientific and other special equipment, but it is principally used in alloys: osmium/iridium alloys are used for tipping fountain pen nibs and for compass bearings.

Iridium in the environment

Potential health effects: Eye: may cause eye irritation. Skin: low hazard for usual industrial handling. Ingestion: may cause irritation of the digestive tract. Expected to be a low ingestion hazard. Inhalation: low hazard for usual industrial handling.

Health effects of iridium

Highly flammable.

Potential health effects: Eye: may cause eye irritation. Skin: low hazard for usual industrial handling. Ingestion: may cause irritation of the digestive tract. Expected to be a low ingestion hazard. Inhalation: low hazard for usual industrial handling.

Environmental effects of iridium

Do not allow product to reach ground water, water bodies or sewage system