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(inorganic chemistry, alchemy) A metal resistant to corrosion, oxidizing and tarnishing, such as gold or platinum.

Periodic table extract showing approximately how often each element tends to be recognized as a noble metal:  7  7  most often (Ru, Rh, Pd, Os, Ir, Pt, Au)  1  1  often (Ag)  2  2  sometimes (Cu, Hg)  6  6  in a limited sense (Tc, Re, As, Sb, Bi, Po) The thick black line encloses the seven to eight metals most often to often so recognized. Silver is sometimes not recognized as a noble metal on account of its greater reactivity. * may be tarnished in moist air or corrode in an acidic solution containing oxygen and an oxidant † attacked by sulfur or hydrogen sulfide § self-attacked by radiation-generated ozone

(inorganic chemistry, alchemy) A metal resistant to corrosion, oxidizing and tarnishing, such as gold or platinum.

One half of a ruthenium bar. Size ~ 40 × 15 × 10 mm Weight ~44 g

(inorganic chemistry, alchemy) A metal resistant to corrosion, oxidizing and tarnishing, such as gold or platinum.

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