Platinum
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]


The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Platinum — Студийный альбом Майк Олдфилд …   Википедия

  • 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, cyandies, sulphur and alkalis.… …   Elements of periodic system

  • platinum — plat‧i‧num [ˈplætnəm] noun [uncountable] a silver grey metal used in manufacturing and traded on commodity market S: • a platinum mine • platinum jewellery * * * platinum UK US /ˈplætɪnəm/ US  /ˈplætənəm/ noun [U] …   Financial and business terms

  • Platinum — 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… …   StarDict's U.S. Gazetteer Places

  • platinum — ☆ platinum [plat′ n əm] n. [ModL < Sp platina, dim. of plata, silver < Prov, metal plate, silver bar, silver < VL * plattus, flat: see PLATE] a silver colored, malleable, ductile, metallic chemical element that is highly resistant to… …   English World dictionary

  • platinum — metallic element, Modern Latin, from Sp. platina platinum, dim. of plata silver, from O.Fr. plate or O.Prov. plata sheet of metal (see PLATE (Cf. plate)). The metal looks like silver, and the Spaniards at first thought it an inferior sort of… …   Etymology dictionary

  • platinum — ► NOUN 1) a precious silvery white metallic chemical element used in jewellery and in some electrical and laboratory apparatus. 2) (before another noun ) greyish white or silvery like platinum. ORIGIN Spanish platina, from plata silver …   English terms dictionary

  • Platinum — This article is about the chemical element. For other uses, see Platinum (disambiguation). iridium ← platinum → gold Pd ↑ Pt ↓ Ds …   Wikipedia

  • platinum — /plat n euhm, plat neuhm/, n. 1. Chem. a heavy, grayish white, highly malleable and ductile metallic element, resistant to most chemicals, practically unoxidizable except in the presence of bases, and fusible only at extremely high temperatures:… …   Universalium

  • Platinum — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Sur les autres projets Wikimedia : « Platinum », sur le Wiktionnaire (dictionnaire universel) Platinum est le mot anglais désignant le… …   Wikipédia en Français

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