palladium

pal·la·di·um ¹  (p-ld-m)

n. Symbol Pd

A soft, ductile, steel-white, tarnish-resistant, metallic element occurring naturally with platinum, especially in gold, nickel, and copper ores. Because it can absorb large amounts of hydrogen, it is used as a purification filter for hydrogen and a catalyst in hydrogenation. It is alloyed for use in electric contacts, jewelry, nonmagnetic watch parts, and surgical instruments. Atomic number 46; atomic weight 106.4; melting point 1,552°C; boiling point 3,140°C; specific gravity 12.02 (20°C); valence 2, 3, 4. See Table at element.

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[From Pallas (discovered at the same time as the element).]

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pal·la·di·um ²  (p-ld-m)

n. pl. pal·la·di·a (-d-) or pal·la·di·ums

1. A safeguard, especially one viewed as a guarantee of the integrity of social institutions: the Bill of Rights, palladium of American civil liberties.

2. A sacred object that was believed to have the power to preserve a city or state possessing it.

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[Middle English Palladion, a statue of Pallas Athena believed to protect Troy, from Old French palladion, from Latin Palladium, from Greek Palladion, from Pallas, Pallad-, Pallas Athena.]

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palladium

Noun

Chem a rare silvery-white element of the platinum metal group, used in jewellery Symbol: Pd[after the asteroid Pallas]

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palladium  (p-ld-m)

Symbol Pd

A malleable, ductile, grayish-white metallic element that occurs naturally with platinum. It is used as a catalyst in hydrogenation and in alloys for making electrical contacts and jewelry. Atomic number 46; atomic weight 106.4; melting point 1,552°C; boiling point 3,140°C; specific gravity 12.02 (20°C); valence 2, 3, 4. See Periodic Table.

Thesaurus

Noun

1.

palladium - a silver-white metallic element of the platinum group that resembles platinum; occurs in some copper and nickel ores; does not tarnish at ordinary temperatures and is used (alloyed with gold) in jewelry atomic number 46, Pd metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.