terbic, adj.
/terr"bee euhm/, n. Chem.
a rare-earth, metallic element present in certain minerals and yielding colorless salts. Symbol: Tb; at. no.: 65; at. wt.: 158.924; sp. gr.: 8.25.
[1835-45; (Yt)terb(y), name of Swedish town where found + -IUM. See YTTERBIUM]

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 (Tb), chemical element, rare-earth metal of the lanthanoid series of the periodic table. One of the least abundant of the rare earths, terbium, when reduced to metallic form, is silvery white and is slowly oxidized by air at room temperatures and by cold water. The element was discovered in 1843 by Carl Gustaf Mosander (Mosander, Carl Gustaf) in a heavy rare-earth fraction called yttria, but its existence was not confirmed for at least 30 years, and pure compounds were not prepared until 1905. Terbium occurs in many rare-earth minerals but is almost exclusively obtained as a by-product from monazite sands, which are a source of thorium. It is also found in the products of nuclear fission. Ion-exchange techniques are utilized for its commercial production. The metal is prepared in a highly pure form by thermoreduction of the anhydrous fluoride with calcium metal. At room temperature the atoms of the pure element adopt the hexagonal close-packed structure. The only isotope occurring in ores is terbium-159. About 20 radioactive artificial isotopes have been prepared, such as terbium-160 (73-day half-life). Sodium terbium borate as a laser material emits coherent light at 5,460 angstroms. In certain solid-state devices terbium is used to dope calcium fluoride, calcium tungstate, and strontium molybdate.

      Terbium is one of a few rare earths that have a +4 as well as a +3 oxidation state. The brown oxide prepared by air ignition has the approximate formula Tb4O7; the oxide TbO2 is obtained by using atomic oxygen. The tetrafluoride TbF4 is prepared by fluorinating the trifluoride; the Tb4+ ion is not known in solution. In other salts and in solution, terbium is present in the +3 oxidation state and behaves as a typical rare earth. Its solutions are pale pink to colourless.

atomic number
atomic weight
melting point
1,360° C
boiling point
3,041° C
specific gravity
8.234 (25° C)
oxidation states
(+4), +3
electronic config.
[Xe]4f 8,95d1,06s2

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Universalium. 2010.

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  • Terbium — (pronEng|ˈtɝbiəm) is a chemical element with the symbol Tb and atomic number 65. Characteristics Terbium is a silvery white rare earth metal that is malleable, ductile and soft enough to be cut with a knife. It is reasonably stable in air (it… …   Wikipedia

  • Terbium — Gadolinium ← Terbium → Dysprosium …   Wikipédia en Français

  • terbium — [ tɛrbjɔm ] n. m. • 1873; de Ytterby, nom de la localité suéd. où fut découvert le minerai ♦ Chim. Élément atomique du groupe des terres rares (Tb; no at. 65; m. at. 158,92). ● terbium nom masculin (de Ytterby, nom d une localité suédoise) Métal… …   Encyclopédie Universelle

  • Terbium — Ter bi*um, n. [NL., fr. Ytterby, in Sweden. See {Erbium}.] (Chem.) A rare metallic element, found in certain minerals, as gadolinite and samarskite, with other rare earths such as ytterbium. Symbol Tb. Atomic number 65. Atomic weight 158.925.… …   The Collaborative International Dictionary of English

  • Terbĭum — Terbĭum, ein Metall, dessen Oxyd neben den Oxyden von Erbium u. Yttrium im Gadolinit vorkommt; wurde 1843 von Mosander entdeckt, ist aber noch nicht rein dargestellt u. nur wenig bekannt. Das Terbiumoxyd (Terbinerde) ist weiß, seine Salze… …   Pierer's Universal-Lexikon

  • Terbĭum — Tb, Metall, findet sich in den Mineralien, welche die »seltenen Erden« (s. d., Bd. 6) enthalten; Terbiumoxyd (Terbinerde) Tb2O3 ist dunkel orangefarben, entfärbt sich durch Glühen in reduzierender Atmosphäre, die Salze sind farblos. Das Metall… …   Meyers Großes Konversations-Lexikon

  • Terbium — Terbĭum, seltenes Edelmetall aus der Yttererde, noch nicht in reinem Zustande isoliert. Atomgewicht 160 …   Kleines Konversations-Lexikon

  • Terbium — Terbium, von Mosander entdecktes Metall, sehr selten vorkommend …   Herders Conversations-Lexikon

  • terbium — Symbol: Tb Atomic number: 65 Atomic weight: 158.924 Silvery metallic element belonging to the lanthanoids. Tb 159 is the only stable isotope, there are seventeen artificial isotopes. Discovered by G.G. Mosander in 1843 …   Elements of periodic system

  • terbium — [tʉr′bē əm] n. [ModL: so named (1843) by Mosander, its discoverer, after Ytterby: see ERBIUM] a soft, silver gray, ductile chemical element, one of the rare earth elements, found in gadolinite and other minerals: symbol, Tb; at. no., 65: see the… …   English World dictionary

  • Terbium — Eigenschaften …   Deutsch Wikipedia

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