Noble metal

File:PT extract noble metalsN.png

This periodic table shows some elements considered noble metals: green almost always, yellow usually, red sometimes, and blue only with specific definitions. Note that, although technetium and polonium may be considered noble, they are radioactive, and their decay products are not necessarily noble.

A noble metal is a metal that has a low chemical reactivity. Normally, this means it is resistant to corrosion and oxidation in air, but more specific definitions exist in different fields of chemistry, with different levels of "nobility" for different elements depending on the definition.

Gold, silver, and the platinum group metals are usually considered noble. Sometimes, mercury and copper can be regarded as noble metals; in specific cases, other elements like rhenium are added.

Some metals like nickel and titanium resist corrosion but are not considered noble because of their other properties, like how they react with oxygen.

Noble metals are valuable, because they are not commonly found in the Earth's crust. They have many uses in everyday things including chemical engineering, electronics, and jewelry.

Noble Metal Media

• Chalcopyrite, which is copper iron sulfide (CuFeS2), is the most abundant copper ore mineral

• One half of a ruthenium bar.Size ~ 40 × 15 × 10 mmWeight ~44 g

• Rhodium: 1 g powder, 1g pressed cylinder, 1 g pellet.

• Palladium (46 Pd).jpg

  The noble metal palladium is very similar to platinum, and, like platinum, is often used for catalysts and for jewellery. Palladium is more reactive than platinum. Palladium has excellent capability to absorb, store, and then release hydrogen.

• Acanthite - Imiter mine, Jbel Saghro, Tinghir, Drâa-Tafilalet, Morocco.jpg

  Acanthite, or silver sulfide (Ag2S)

• Osmium crystals.jpg

  Osmium Os, crystals, purity ≥ 99.99%, 2.2 g. Produced by chemical transport reaction in chlorine gas

• Iridium-2.jpg

  Pieces of pure iridium, 1 g, size: 1–3 mm each

• Platinum crystals.jpg

  Crystals of pure platinum grown by gas phase transport.

Related pages

• Precious metal
• Noble gas