Platinum sponge
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 sponge — Sponge Sponge (sp[u^]nj), n. [OF. esponge, F. [ e]ponge, L. spongia, Gr. spoggia , spo ggos. Cf. {Fungus}, {Spunk}.] [Formerly written also {spunge}.] 1. (Zo[ o]l.) Any one of numerous species of Spongi[ae], or Porifera. See Illust. and Note… …   The Collaborative International Dictionary of English

  • platinum sponge — noun : metallic platinum in a gray porous spongy form that is obtained by reducing ammonium chloroplatinate, that occludes large volumes of oxygen, hydrogen, and other gases, and that is used as a catalyst * * * spongy platinum or platinum sponge …   Useful english dictionary

  • Platinum black — (Pt black) is a fine powder of platinum with good catalytic properties. The name of platinum black is due to its black color. Platinum black is widely used as a thin film covering solid platinum metal, forming platinum electrodes for applications …   Wikipedia

  • Sponge — (sp[u^]nj), n. [OF. esponge, F. [ e]ponge, L. spongia, Gr. spoggia , spo ggos. Cf. {Fungus}, {Spunk}.] [Formerly written also {spunge}.] 1. (Zo[ o]l.) Any one of numerous species of Spongi[ae], or Porifera. See Illust. and Note under {Spongi[ae]} …   The Collaborative International Dictionary of English

  • Sponge cake — Sponge Sponge (sp[u^]nj), n. [OF. esponge, F. [ e]ponge, L. spongia, Gr. spoggia , spo ggos. Cf. {Fungus}, {Spunk}.] [Formerly written also {spunge}.] 1. (Zo[ o]l.) Any one of numerous species of Spongi[ae], or Porifera. See Illust. and Note… …   The Collaborative International Dictionary of English

  • Sponge lead — Sponge Sponge (sp[u^]nj), n. [OF. esponge, F. [ e]ponge, L. spongia, Gr. spoggia , spo ggos. Cf. {Fungus}, {Spunk}.] [Formerly written also {spunge}.] 1. (Zo[ o]l.) Any one of numerous species of Spongi[ae], or Porifera. See Illust. and Note… …   The Collaborative International Dictionary of English

  • Sponge tree — Sponge Sponge (sp[u^]nj), n. [OF. esponge, F. [ e]ponge, L. spongia, Gr. spoggia , spo ggos. Cf. {Fungus}, {Spunk}.] [Formerly written also {spunge}.] 1. (Zo[ o]l.) Any one of numerous species of Spongi[ae], or Porifera. See Illust. and Note… …   The Collaborative International Dictionary of English

  • 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,… …   The Collaborative International Dictionary of English

  • Platinum black — 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… …   The Collaborative International Dictionary of English

  • Platinum lamp — 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… …   The Collaborative International Dictionary of English

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