Search Result for "platinum": 
Wordnet 3.0

NOUN (1)

1. a heavy precious metallic element; grey-white and resistant to corroding; occurs in some nickel and copper ores and is also found native in some deposits;
[syn: platinum, Pt, atomic number 78]

The Collaborative International Dictionary of English v.0.48:

Platinum \Plat"i*num\, n. [NL., fr. Sp. platina, from plata silver, LL. plata a thin plate of metal. See Plate, and cf. Platina.] (Chem.) A metallic element of atomic number 78, one of the noble metals, classed with silver and gold as a precious metal, occurring native or alloyed with other metals and also as the platinum arsenide (sperrylite). It is a heavy tin-white metal which is ductile and malleable, but very infusible (melting point 1772[deg] C), and characterized by its resistance to strong chemical reagents. It is used for crucibles in laboratory operations, as a catalyst, in jewelry, for stills for sulphuric acid, rarely for coin, and in the form of foil and wire for many purposes. Specific gravity 21.5. Atomic weight 195.1. Symbol Pt. Formerly called platina. [1913 Webster +PJC] Platinum black (Chem.), a soft, dull black powder, consisting of finely divided metallic platinum obtained by reduction and precipitation from its solutions. It absorbs oxygen to a high degree, and is employed as an oxidizer. Platinum lamp (Elec.), a kind of incandescent lamp of which the luminous medium is platinum. See under Incandescent. Platinum metals (Chem.), the group of metallic elements which in their chemical and physical properties resemble platinum. These consist of the light platinum group, viz., rhodium, ruthenium, and palladium, whose specific gravities are about 12; and the heavy platinum group, viz., osmium, iridium, and platinum, whose specific gravities are over 21. Platinum sponge (Chem.), metallic platinum in a gray, porous, spongy form, obtained by reducing the double chloride of platinum and ammonium. It absorbs oxygen, hydrogen, and certain other gases, to a high degree, and is employed as an agent in oxidizing. [1913 Webster]
WordNet (r) 3.0 (2006):

platinum n 1: a heavy precious metallic element; grey-white and resistant to corroding; occurs in some nickel and copper ores and is also found native in some deposits [syn: platinum, Pt, atomic number 78]
The Elements (07Nov00):

platinum Symbol: Pt Atomic number: 78 Atomic weight: 195.078 Attractive greyish-white metal. When pure, it is malleable and ductile. Does not oxidize in air, insoluble in hydrochloric and nitric acid. Corroded by halogens, cyanides, sulphur and alkalis. Hydrogen and oxygen react explosively in the presence of platinum. There are six stable isotopes and three radioisotopes, the most stable being Pt-193 with a half-life of 60 years. Platinum is used in jewelry, laboratory equipment, electrical contacts, dentistry, and anti-pollution devices in cars. PtCl2(NH3)2 is used to treat some forms of cancer. Platinum-cobalt alloys have magnetic properties. It is also used in the definition of the Standard Hydrogen Electrode. Discovered by Antonio de Ulloa in South America in 1735. The name comes from the Spanish word platina which means silver. Platinum metal is generally not a health concern due to its unreactivity, however platinum compounds should be considered highly toxic.
U.S. Gazetteer Places (2000):

Platinum, AK -- U.S. city in Alaska Population (2000): 41 Housing Units (2000): 26 Land area (2000): 44.630629 sq. miles (115.592794 sq. km) Water area (2000): 0.071778 sq. miles (0.185904 sq. km) Total area (2000): 44.702407 sq. miles (115.778698 sq. km) FIPS code: 61080 Located within: Alaska (AK), FIPS 02 Location: 59.006890 N, 161.815290 W ZIP Codes (1990): 99651 Note: some ZIP codes may be omitted esp. for suburbs. Headwords: Platinum, AK Platinum