Noble Metals

You may have heard certain metals called noble metals. Here is a look at what the noble metals are, which metals are included and the properties of the noble metals.

What Are the Noble Metals?

The noble metals are a group of metals that resist oxidation and corrosion in moist air. They are the opposite of the base metals, which more readily oxidize and corrode.

Which Metals Are Noble Metals?

There is more than one list of noble metals. The following metals are considered noble metals (listed in order of increasing atomic number):

• ruthenium
• rhodium
• palladium
• silver
• osmium
• iridium
• platinum
• gold

Sometimes mercury is listed as a noble metal. Other lists include rhenium as a noble metal. Strangely, not all corrosion-resistant metals are considered to be noble metals. For example, although titanium, niobium and tantalum are extremely corrosion-resistant, they are not noble metals.

Physics Definition of Noble Metals

Chemistry allows for a loose definition of noble metals, but the physics definition is more restrictive. In physics, a noble metal is one which has filled electronic d-bands. According to this definition, only gold, silver and copper are noble metals.

View the Chart of Noble and Precious Metals.