Noble metals are those metals that are highly resistant to chemical reactions, in particular highly resistant to oxidation and corrosion. This general characteristic makes noble metals very useful in various applications. The noble metals are the following:
- Ruthenium (Ru)
- Rhodium (Rh). It is the metal shown in the photograph.
- Palladium (Pd)
- Silver (Ag)
- Osmium (Os)
- Iridium (Go)
- Platinum (Pt)
- Gold (Au)
Mercury (Hg) and rhenium (Rn) can also be considered noble metals. Copper (Cu) can also be considered noble or semi-noble.
Noble metals retain their bright color when exposed to the atmosphere because they are highly resistant to oxidation, while other metals lose their shine when their surface is covered by a layer of oxide from the metal itself. The definition and classification of metals as noble is not rigorous, since there are metals that are also resistant to corrosion such as titanium, niobium or tantalum which, even though they are, are not considered noble metals.
From the point of view of atomic structure, only those with a complete d electron shell are considered noble metals . These elements are copper, silver and gold.
Most noble metals are valuable and rare, but the definition of a noble metal differs from that of a precious metal.
Fountain
- Brooks, Robert R., ed. (1992). Noble Metals and Biological Systems: Their Role in Medicine, Mineral Exploration, and the Environment . Boca Raton, Fla.: CRC Press. ISBN 9780849361647.
