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单词 platinum
释义

platinum


Plat·i·num

P0360700 (plăt′n-əm)n. A trademark for a certification indicating that a recording, such as an album of music, has sold a million copies.

plat·i·num

P0360700 (plăt′n-əm)n.1. Symbol Pt A silver-white metallic element occurring in alluvial deposits in sperrylite and nickel ores, usually mixed with other metals such as iridium, osmium, or nickel. It is ductile and malleable, does not oxidize in air, and is used as a catalyst and in electrical components, jewelry, dentistry, and electroplating. Atomic number 78; atomic weight 195.08; melting point 1,768.2°C; boiling point 3,825°C; specific gravity 21.45 (20°C); valence 2, 3, 4. See Periodic Table.2. A medium to light gray.
[New Latin, from Spanish platina, platinum; see platina.]

platinum

(ˈplætɪnəm) n1. (Elements & Compounds) a ductile malleable silvery-white metallic element, very resistant to heat and chemicals. It occurs free and in association with other platinum metals, esp in osmiridium: used in jewellery, laboratory apparatus, electrical contacts, dentistry, electroplating, and as a catalyst. Symbol: Pt; atomic no: 78; atomic wt: 195.08; valency: 1–4; relative density: 21.45; melting pt: 1769°C; boiling pt: 3827±100°C2. (Colours) a. a medium to light grey colourb. (as adjective): a platinum carpet. [C19: New Latin, from platina, on the model of other metals with the suffix -um]

plat•i•num

(ˈplæt n əm, ˈplæt nəm)

n. 1. a heavy, grayish white, highly malleable and ductile metallic chemical element, resistant to most chemicals, practically unoxidizable except in the presence of bases, and fusible only at extremely high temperatures: used for making chemical and scientific apparatus, as a catalyst in the oxidation of ammonia to nitric acid, and in jewelry. Symbol: Pt; at. wt.: 195.09; at. no.: 78; sp. gr.: 21.5 at 20°C. 2. a light, metallic gray with very slight bluish tinge when compared with silver. adj. 3. (of a recording, compact disc, or cassette) having sold a minimum of one million copies. [1805–15; < New Latin, alter. of earlier platina < Sp; see platina]

plat·i·num

(plăt′n-əm) Symbol Pt A soft, easily shaped, silver-white metallic element that occurs worldwide with similar metals. It has a high melting point and does not corrode in air. Platinum is used as a catalyst and in making jewelry, electrical contacts, and dental crowns. Atomic number 78. See Periodic Table.
Thesaurus
Noun1.platinum - a heavy precious metallic elementplatinum - 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 depositsatomic number 78, Ptnoble metal - any metal that is resistant to corrosion or oxidation
Translations
白金铂

platinum

(ˈplӕtinəm) noun, adjective (of) an element, a heavy, valuable grey metal, often used in making jewellery. a platinum ring. 鉑,白金 铂,白金

platinum

白金zhCN

IdiomsSeego platinum

platinum


platinum

(plăt`ənəm), metallic chemical element; symbol Pt; at. no. 78; at. wt. 195.084; m.p. 1,772&degC;; b.p. 3,827±100&degC;; sp. gr. 21.45 at 20&degC;; valence +2 or +4. Pure platinum is a malleable, ductile, lustrous, silver-white metal with a face-centered cubic crystalline structure. Chemically inactive, it is unaffected by common acids but dissolves in aqua regiaaqua regia
[Lat.,=royal water], corrosive, fuming yellow liquid prepared by mixing one volume of concentrated nitric acid with three to four volumes of concentrated hydrochloric acid.
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, forming chloroplatinic acid (H2PtCl6). It is attacked by the halogens, sulfur, or caustic alkalies. It does not combine with oxygen even at high temperatures. Like palladium, it absorbs large quantities of hydrogen, which it releases at red heat.

Platinum is found in nature alloyed with the other metals of the so-called platinum group, found in Group 10 of the periodic tableperiodic table,
chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
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; the other five metals in this group are iridiumiridium
, metallic chemical element; symbol Ir; at. no. 77; at. wt. 192.217; m.p. about 2,410&degC;; b.p. about 4,130&degC;; sp. gr. 22.55 at 20&degC;; valence +3 or +4.
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, osmiumosmium
, metallic chemical element; symbol Os; at. no. 76; at. wt. 190.23; m.p. 3,045±30&degC;; b.p. 5,027±100&degC;; sp. gr. 22.57 at 20&degC;; valence usually +0 to +8.
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, palladiumpalladium
[Gr. Pallas, goddess of wisdom], metallic chemical element; symbol Pd; at. no. 46; at. wt. 106.42; m.p. 1,554&degC;; b.p. 2,970&degC;; sp. gr. 12.02 at 20&degC;; valence +2, +3, or +4.
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, rhodiumrhodium
, metallic chemical element; symbol Rh; at. no. 45; at. wt. 102.90550; m.p. about 1,966&degC;; b.p. 3,727±100&degC;; sp. gr. 12.41 at 20&degC;; valence +2, +3, +4, +5, or +6.
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, and rutheniumruthenium
, metallic chemical element; symbol Ru; at. no. 44; at. wt. 101.07; m.p. about 2,310&degC;; b.p. about 3,900&degC;; sp. gr. 12.41 at 20&degC;; valence commonly +2, +3, +4, +6, or +8.
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. These metals are found in alluvial deposits in Russia, South Africa, Colombia, and Alaska. Platinum and the related metals are recovered commercially as a byproduct of the refining of nickel ores mined near Sudbury, Ont., Canada; from gold mines in South Africa; and from the alluvial deposits in Russia. There is no routine method for separating platinum from other metals; it is usually recovered by complex chemical methods.

Platinum has many uses. Its wear- and tarnish-resistance characteristics are well-suited for making fine jewelry. Platinum and its alloys are used in surgical tools, laboratory utensils, electrical resistance wires, and electrical contact points. The most important of the alloys are those with iridium. The International Prototype Kilogram, kept at Sèvres, France, is a cylinder of platinum-iridium alloy, and the standard definition of a meter for a long time was based on the distance between two marks on a bar of platinum-iridium. Platinum is also used in the definition of the Standard Hydrogen Electrode (a reference for determining cell voltages). Because its thermal coefficient of expansion is nearly equal to that of glass, platinum is used to make electrodes sealed in glass. It is used extensively in dentistry and a platinum-osmium alloy is used in implants such as pacemakers and replacement valves. A platinum-cobalt alloy is used to make very powerful magnets.

Platinum is specially prepared for use as a catalystcatalyst,
substance that can cause a change in the rate of a chemical reaction without itself being consumed in the reaction; the changing of the reaction rate by use of a catalyst is called catalysis.
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. Finely divided, the metal is platinum black, a powder. It also may be used as platinum sponge, formed when platinic ammonium chloride, (NH4)2PtCl6, is ignited, or as platinized asbestos, prepared by heating asbestos after dipping it in chloroplatinic acid. Platinum catalysts are used in the contact process for producing sulfuric acid, in the Ostwald process for the production of nitric acid, and in petroleum cracking, as well as in a variety of other reactions. Platinum is also used as a catalyst in fuel cells and in catalytic converters for automobiles.

Naturally-occurring platinum and platinum-rich alloys have been known since antiquity. Although there is evidence that the metal was used in the Americas in pre-Columbian times, the first European reference to platinum appears in 1557 as a description of a mysterious metal found in Central American mines. When the Spanish first encountered the metal, they regarded it as an undesirable impurity in the silver they were mining and often discarded it.

Modern knowledge of the metal dates from about 1736, when its existence in South America was reported by A. de Ulloa. Some of this platina [little silver], was taken to England, and soon thereafter many leading chemists published reports on it. A process discovered about 1803 by W. H. Wollaston for making the metal malleable made possible its commercial use for laboratory apparatus and other purposes. Although platinum was used as an adulterant for gold over a century ago, it is now considered the more valuable of the two.

Platinum

 

Pt, a chemical element of Group VIII of the Mendeleev periodic system. Atomic number, 78; atomic weight, 195.09. A heavy, high-melting metal. (For information on platinum, as well as on ruthenium, rhodium, palladium, osmium, and iridium, which are accessory minerals of platinum in the earth’s crust and have similar properties, see; ; and .)

platinum

[′plat·ən·əm] (chemistry) A chemical element, symbol Pt, atomic number 78, atomic weight 195.08. (metallurgy) A soft, ductile, malleable, grayish white noble metal with relatively high electric resistance; used in alloys, in electrical and electronic devices, and in jewelry.

platinum

1. a ductile malleable silvery-white metallic element, very resistant to heat and chemicals. It occurs free and in association with other platinum metals, esp in osmiridium: used in jewellery, laboratory apparatus, electrical contacts, dentistry, electroplating, and as a catalyst. Symbol: Pt; atomic no.: 78; atomic wt.: 195.08; valency: 1--4; relative density: 21.45; melting pt.: 1769°C; boiling pt.: 3827±100°C 2. a. a medium to light grey colour b. (as adjective): a platinum carpet

Platinum

(Platinum Technology, Inc., Oakbrook Terrace, IL, www.platinum.com) A major software vendor acquired by Computer Associates in 1999, with more than 160 data, systems and application software products to its credit. Founded in 1987, Platinum's key business areas were database and systems management, application life cycle, data warehousing, the Internet and Y2K compliance. Key alliances with HP, IBM, Intel, Microsoft and SAP helped the company expand to more than 40 countries.

platinum


platinum

 (Pt) [plat´ĭ-num] a chemical element, atomic number 78, atomic weight 195.09. (See Appendix 6.)

plat·i·num (Pt),

(plat'i-nŭm), A metallic element, atomic no. 78, atomic wt. 195.08, used for making small parts for chemical apparatus because of its resistance to acids; in powdered form (platinum black), it is an important catalyst in hydrogenation. Some of its salts have been used to treat syphilis. A derivative, cisplatin, is used as an antineoplastic agent. [Mod. L., originally platina, fr. Sp. plata, silver]

platinum

Toxicology A metallic element–atomic number 78, atomic weight 195.1, used in catalytic converters for cars, various industries, dental restorations, chemotherapy–eg, cisplatin and carboplatin

plat·i·num

(plat'i-nŭm) A metallic element, atomic no. 78, atomic wt. 195.08, used for making small parts for chemical apparatus because of its resistance to acids; in powdered form (platinum black), it is an important catalyst in hydrogenation. A derivative, cisplatin, is used as an antineoplastic agent. [Mod. L., originally platina, fr. Sp. plata, silver]

plat·i·num

(plat'i-nŭm) A metallic element used for making small parts for chemical apparatus because of its resistance to acids; its pow dered form (platinum black) is an important catalyst in hydrogenation. Some salts have been used to treat syphilis; one derivative, cisplatin, is used as an antineoplastic agent. [Mod. L., originally platina, fr. Sp. plata, silver]

Patient discussion about platinum

Q. I was told that platinum is used in fragrances for the fullness of the spray. Please tell me more! Three years ago I was diagnosed with off the lab chart levels of platinum in my body. I have no hobby or avenue for exposure other than my work. I have sold fragrances for over ten years. Even the Regional EPA Air Quality person doesnt know where I am getting this. I was told by a health director who made some calls. He told me that platinum is used in fragrances for the "fullness of the spray". Would you please tell me more about this? Thank you!A. Thank you Joseph83! What list of materials shall I look at? I know that the FDA doesn't regulate these products; also, I wonder if there is a masking name for platinum. I have so much of this in me, it just has to come from somewhere! I'm amazed that the EPA SUPPOSEDLY doesn't know where its coming from either.

More discussions about platinum

Platinum


Platinum

A rare and valuable metal. Platinum is used in jewelry and electronics. Platinum is traded as a commodity on various security exchanges. Platinum is volatile like other commodities, but generally maintains a relatively high price.
See PT
See PLT

platinum


  • noun

Synonyms for platinum

noun a heavy precious metallic element

Synonyms

  • atomic number 78
  • Pt

Related Words

  • noble metal
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