Iridium

Iridium is a very dense, hard, and corrosion resistant transition metal belonging to the platinum group. It is one of the rarest elements in Earth’s crust and is typically obtained as a byproduct of nickel and platinum mining. Iridium is silvery white, has an extremely high melting point of about 2 446 °C, and is known for being the most corrosion resistant metal, even at high temperatures. Because of its stability and catalytic properties, iridium is used in specialised applications such as spark plugs, medical devices, high performance alloys and, increasingly, in proton exchange membrane electrolysers for green hydrogen production. Its scarcity and high cost make efficient use crucial for scaling clean energy technologies.