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A noble metal is ordinarily regarded as a metallic element that is generally resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals (ruthenium, rhodium, palladium, osmium, iridium) are most often so classified.
The galvanic series (or electropotential series) determines the nobility of metals and semi-metals. When two metals are submerged in an electrolyte, while also electrically connected by some external conductor, the less noble (base) will experience galvanic corrosion. The rate of corrosion is determined by the electrolyte, the difference in ...
The best known precious metals are the precious coinage metals, which are gold and silver. Although both have industrial uses, they are better known for their uses in art , jewelry , and coinage. Other precious metals include the platinum group metals: ruthenium , rhodium , palladium , osmium , iridium , and platinum , of which platinum is the ...
Rhodium, a noble metal, shown here as 1 g of powder, a 1 g pressed cylinder, and a 1 g pellet. The term noble metal (also for elements) is commonly used in opposition to base metal. Noble metals are less reactive, resistant to corrosion or oxidation, [49] unlike most base metals. They tend to be precious metals, often due to perceived rarity.
Gold has the highest electron affinity of any metal, at 222.8 kJ/mol, making Au − a stable species, [13] analogous to the halides. Gold also has a –1 oxidation state in covalent complexes with the group 4 transition metals, such as in titanium tetraauride and the analogous zirconium and hafnium compounds.
For example, copper is added to the precious metal silver to make a more durable alloy for use in coins, housewares and jewelry. Coin silver, which was used for making silver coins in the past, contains 90% silver and 10% copper, by mass. Sterling silver contains 92.5% silver and 7.5% of other metals, usually copper, by mass.
Precious metals (9 C, ... Pages in category "Noble metals" The following 11 pages are in this category, out of 11 total. This list may not reflect recent changes. ...
The Platinum Metals and their Alloys. New York: The International Nickel Company, Inc., 1941: 16. — "Values ranging from 21.3 to 21.5 gm/cm 3 at 20 °C have been reported for the density of annealed platinum; the best value being about 21.45 gm/cm 3 at 20 °C." 21.46 g/cm 3 — Rose, T. Kirke. The Precious Metals, Comprising Gold, Silver and ...