A noble metal is a metal or alloy characterized by it lack of chemical reactivity. These metals resist oxidation and corrosion in any environment. They are the opposite of base metals, which more readily oxidize and corrode.
The noble metals are:
- Platinum group, including palladium, iridium, rhodium, ruthenium, and osmium (metals of groups VIIB, VIII, and IB of the second and third transition series of the periodic table)
Platinum-group metals are commonly used as catalysts in automotive pollution control equipment and for making the spinnerets used in the manufacture of synthetic fibers for clothing. Silver is used in photographic processes. Gold is used for palladium, and its alloys in printed circuit boards. Silver, gold and platinum-group metals are all used for electrical contacts. Organic metallic compounds containing platinum are used for cancer chemotherapy drugs and many other applications.