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Iridium is a member of the platinum group metals (PGM). It is famous as a the element that revealed that the dinosaurs were killed by an asteroid 65 million years ago. Iridium is the second densest element, second to osmium. Iridium is also very chemical resistent and is used in high temperature crucibles used for high purity crystal production.

It is a hard, brittle silver white metal with a melting point of 2446 °C (​4435 °F) and density of 22.56 g/cm3.



Chemical reactions

Iridium is extremely inert when it comes to chemical reactions. It is not attacked by most acids, aqua regia, by most molten metals or even molten silicates. Below 2000 °C oxygen doesn't affect solid pieces of iridium.

Fine powdered iridium reacts with oxygen and halogens when heated to red heat.

Catalysts based on iridium instead of platinum can sometimes boost production in chemical plants.

Iridium can be oxidized by a peroxide fusion into IrO2.

Iridium compounds

( Main article List of iridium compounds )

Iridium can take oxidation states between -3 and +9 so there are a lot of possible compounds that can be formed with iridium. Most commonly is +3 and +4 compounds.

Some compounds :

An iridium based organic LED material has been discovered and could provide a scrap source of iridium in the future.

Melting iridium

The easiest way to melt iridium is to use induction melting. The high melting point of iridium makes it just barely possible to melt with an oxygen hydrogen torch.

Refining iridium

(Main article iridium refining)

Patents :



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