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单词 tungsten
释义
tungsten

Chemistry
  • A white or grey metallic transition element (formerly called wolfram); a.n. 74; r.a.m. 183.85; r.d. 19.3; m.p. 3410°C; b.p. 5660°C. It is found in a number of ores, including the oxides wolframite, (Fe,Mn)WO4, and scheelite, CaWO4. The ore is heated with concentrated sodium hydroxide solution to form a soluble tungstate. The oxide WO3 is precipitated from this by adding acid, and is reduced to the metal using hydrogen. It is used in various alloys, especially high-speed steels (for cutting tools) and in lamp filaments. Tungsten forms a protective oxide in air and can be oxidized at high temperature. It does not dissolve in dilute acids. It forms compounds in which the oxidation state ranges from +2 to +6. The metal was first isolated by Juan d’Elhuyer and Fausto d’Elhuyer (1755–1833) in 1783.

    https://www.webelements.com/tungsten/ Information from the WebElements site


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