Terbium 30045 225684108 2008-07-14T21:57:34Z Arkuat 29003 /* Characteristics */ section title according to wikiproject elements {{Elementbox_header | number=65 | symbol=Tb | name=terbium | left=[[gadolinium]] | right=[[dysprosium]] | above=- | below=[[berkelium|Bk]] | color1=#ffbfff | color2=black }} {{Elementbox_series | [[lanthanide]]s }} {{Elementbox_periodblock | period=6 | block=f }} {{Elementbox_appearance_img | Tb,65| silvery white }} {{Elementbox_atomicmass_gpm | [[1 E-25 kg|158.92535]][[List of elements by atomic mass|(2)]] }} {{Elementbox_econfig | &#91;[[xenon|Xe]]&#93; 4f<sup>9</sup> 6s<sup>2</sup> }} {{Elementbox_epershell | 2, 8, 18, 27, 8, 2 }} {{Elementbox_section_physicalprop | color1=#ffbfff | color2=black }} {{Elementbox_phase | [[solid]] }} {{Elementbox_density_gpcm3nrt | 8.23 }} {{Elementbox_densityliq_gpcm3mp | 7.65 }} {{Elementbox_meltingpoint | k=1629 | c=1356 | f=2473 }} {{Elementbox_boilingpoint | k=3503 | c=3230 | f=5846 }} {{Elementbox_heatfusion_kjpmol | 10.15 }} {{Elementbox_heatvaporiz_kjpmol | 293 }} {{Elementbox_heatcapacity_jpmolkat25 | 28.91 }} {{Elementbox_vaporpressure_katpa | 1789 | 1979 | (2201) | (2505) | (2913) | (3491) | comment= }} {{Elementbox_section_atomicprop | color1=#ffbfff | color2=black }} {{Elementbox_crystalstruct | hexagonal }} {{Elementbox_oxistates | 3, 4<br />(weakly [[base (chemistry)|basic]] oxide) }} {{Elementbox_electroneg_pauling | ? 1.2 }} {{Elementbox_ionizationenergies4 | 565.8 | 1110 | 2114 }} {{Elementbox_atomicradius_pm | [[1 E-10 m|175]] }} {{Elementbox_atomicradiuscalc_pm | [[1 E-10 m|225]] }} {{Elementbox_section_miscellaneous | color1=#ffbfff | color2=black }} {{Elementbox_magnetic | [[ferromagnetism|ferromagnetic]]<br />in [[dry ice]] [http://www.irm.umn.edu/quarterly/irmq10-3.pdf] }} {{Elementbox_eresist_ohmm | ([[room temperature|r.t.]]) (α, poly)<br />1.150 µ}} {{Elementbox_thermalcond_wpmkat300k | 11.1 }} {{Elementbox_thermalexpansion_umpmk | ([[room temperature|r.t.]]) (α, poly)<br />10.3 }} {{Elementbox_speedofsound_rodmpsat20 | 2620 }} {{Elementbox_youngsmodulus_gpa | (α form) 55.7 }} {{Elementbox_shearmodulus_gpa | (α form) 22.1 }} {{Elementbox_bulkmodulus_gpa | (α form) 38.7 }} {{Elementbox_poissonratio | (α form) 0.261 }} {{Elementbox_vickershardness_mpa | 863 }} {{Elementbox_brinellhardness_mpa | 677 }} {{Elementbox_cas_number | 7440-27-9 }} {{Elementbox_isotopes_begin | color1=#ffbfff | color2=black }} {{Elementbox_isotopes_decay | mn=157 | sym=Tb | na=[[synthetic radioisotope|syn]] | hl=[[1 E s|71 y]] | dm=[[electron capture|ε]] | de=0.060 | pn=157 | ps=[[gadolinium|Gd]] }} {{Elementbox_isotopes_decay2 | mn=158 | sym=Tb | na=[[synthetic radioisotope|syn]] | hl=[[1 E s|180 y]] | dm1=ε | de1=1.220 | pn1=158 | ps1=[[gadolinium|Gd]] | dm2=[[beta minus decay|β<sup>-</sup>]] | de2=0.937 | pn2=158 | ps2=[[dysprosium|Dy]] }} {{Elementbox_isotopes_stable | mn=159 | sym=Tb | na=100% | n=94 }} {{Elementbox_isotopes_end}} {{Elementbox_footer | color1=#ffbfff | color2=black }} '''Terbium''' ({{pronEng|ˈtɝbiəm}}) is a [[chemical element]] with the symbol '''Tb''' and [[atomic number]] 65. == Characteristics == Terbium is a silvery-white [[Rare earth element|rare earth]] [[metal]] that is [[malleable]], [[ductile]] and soft enough to be cut with a knife. It is reasonably stable in air, and two crystal [[Allotropy|allotropes]] exist, with a transformation temperature of 1289 °C. Terbium(III) cation is brilliantly [[Fluorescence|fluorescent]], in a beautiful bright lemon-yellow color that is the result of a strong green [[emission line]] in combination with other lines in the orange and red. The [[yttrofluorite]] variety of the mineral [[fluorite]] owes its creamy-yellow fluorescence in part to terbium. == Applications == Terbium is used to [[Dopant|dope]] [[calcium fluoride]], calcium [[tungstate]] and [[strontium]] [[molybdate]], materials that are used in solid-state devices, and as a crystal stabilizer of [[fuel cell]]s which operate at elevated temperatures, together with [[zirconium(IV) oxide|ZrO<sub>2</sub>]]. Terbium is also used in [[alloy]]s and in the production of electronic devices. As a component of [[Terfenol-D]] (an alloy that expands or contracts to a high degree in the presence of a magnetic field), terbium is of use in [[actuator]]s, [[sensor]]s and other magenetomechanical devices. Terbium [[oxide]] is used in green [[phosphor]]s in [[fluorescent lamp]]s and color TV tubes. [[Sodium]] terbium [[borate]] is used in [[solid state (electronics)|solid state]] devices. The brilliant fluorescence allows terbium to be used as a probe in biochemistry, where it somewhat resembles [[calcium]] in its behavior. Terbium "green" phosphors (which fluoresce a brilliant lemon-yellow) are combined with divalent [[Europium]] blue phosphors and trivalent europium red phosphors to provide the "trichromatic" lighting technology, which is by far the largest consumer of the world's terbium supply. Trichromatic lighting provides much higher light output for a given amount of electrical energy than does [[incandescent light]]ing. == History == Terbium was discovered in [[1843]] by [[Sweden|Swedish]] [[chemist]] [[Carl Gustaf Mosander]], who detected it as an impurity in [[Yttrium]]-oxide, Y<sub>2</sub>O<sub>3</sub>, and named after the village [[Ytterby]] in [[Sweden]]. It was not isolated in pure form until the recent advent of [[ion exchange]] techniques. When Mosander first partitioned "yttria" into three fractions, "terbia" was the fraction that contained the pink color (due to what is now known as erbium), and "erbia" was the fraction that was essentially colorless in solution, but gave a brown-tinged oxide. Later workers had difficulty in observing the latter, but the pink fraction was impossible to miss. Arguments went back and forth as to whether "erbia" even existed. In the confusion, the original names got reversed, and the exchange of names stuck. It is now thought that those workers who used the double sodium or potassium sulfates to remove "ceria" from "yttria" inadvertently lost the terbium content of the system into the ceria-containing precipitate. In any case, what is now known as terbium was only about 1% of the original yttria, but that was sufficient to impart a yellowish color to the oxide. Thus, terbium was a minor component in the original terbium fraction, dominated by its immediate neighbors, gadolinium and dysprosium. Thereafter, whenever other rare earths were teased apart from this mixture, whichever fraction gave the brown oxide retained the terbium name, until at last it was pure. The 19th century investigators did not have the benefit of fluorescence technology, wherewith to observe the brilliant fluorescence that would have made this element much easier to track in mixtures. == Occurrence == Terbium is never found in nature as a free element, but it is contained in many [[mineral]]s, including [[cerite]], [[gadolinite]], [[monazite]] ((Ce,LaTh,Nd,Y)PO<sub>4</sub>, which contains up to 0.03% of terbium), [[xenotime]] (YPO<sub>4</sub>) and [[euxenite]] ((Y,Ca,Er,La,Ce,U,Th)(Nb,Ta,Ti)<sub>2</sub>O<sub>6</sub>, which contains 1% or more of terbium). The richest current commercial sources of terbium are the ion-adsorption [[clay]]s of [[southern China]]. The high-yttrium concentrate versions of these are about two-thirds yttrium oxide by weight, and about 1% terbia. However, small amounts occur in [[bastnäsite]] and [[monazite]], and when these are processed by solvent-extraction to recover the valuable heavy lanthanides in the form of "[[samarium]]-[[europium]]-[[gadolinium]] concentrate" (''SEG concentrate''), the terbium content of the ore ends up therein. Due to the large volumes of bastnäsite processed, relative to the richer ion-adsorption clays, a significant proportion of the world's terbium supply comes from bastnäsite. == Compounds == Terbium compounds include: * [[Fluoride]]s: [[terbium(III) fluoride|TbF<sub>3</sub>]], [[terbium(IV) fluoride|TbF<sub>4</sub>]] * [[Chloride]]s: [[terbium(III) chloride|TbCl<sub>3</sub>]] * [[Bromide]]s: [[terbium(III) bromide|TbBr<sub>3</sub>]] * [[Iodide]]s: [[terbium(III) iodide|TbI<sub>3</sub>]] * [[Oxide]]s: [[terbium(III) oxide|Tb<sub>2</sub>O<sub>3</sub>]], [[terbium(III,IV) oxide|Tb<sub>4</sub>O<sub>7</sub>]] * [[Sulfide]]s: [[terbium(III) sulfide|Tb<sub>2</sub>S<sub>3</sub>]] * [[Nitride]]s: [[terbium(III) nitride|TbN]] ''See also [[:Category:Terbium compounds|terbium compounds]].'' == Isotopes == {{main|isotopes of terbium}} Naturally occurring terbium is composed of 1 stable [[isotope]], 159-Tb. 33 [[radioisotope]]s have been characterized, with the most stable being 158-Tb with a [[half-life]] of 180 years, 157-Tb with a half-life of 71 years, and 160-Tb with a half-life of 72.3 days. All of the remaining [[radioactive]] isotopes have half-lifes that are less than 6.907 days, and the majority of these have half lifes that are less than 24 seconds. This element also has 18 [[meta state]]s, with the most stable being 156m1-Tb (t<sub>½</sub> 24.4 hours), 154m2-Tb (t<sub>½</sub> 22.7 hours) and 154m1-Tb (t<sub>½</sub> 9.4 hours). The primary [[decay mode]] before the most abundant stable isotope, 159-Tb, is [[electron capture]], and the primary mode behind is [[beta minus decay]]. The primary [[decay product]]s before 159-Tb are element Gd ([[gadolinium]]) isotopes, and the primary products behind are element Dy ([[dysprosium]]) isotopes. == Precautions == As with the other [[lanthanide]]s, terbium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail. Terbium has no known biological role. == References == *[http://periodic.lanl.gov/elements/65.html Los Alamos National Laboratory &ndash; Terbium] == Further reading == * {{cite journal|title=Higher Oxides of the Lanthanide Elements: Terbium Dioxide|author=D.M. Gruen, W.C. Koehler, and J.J. Katz|date=April 1951|pages=1475|journal=Journal of the American Chemical Society|format=PDF|url=http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1951/73/i04/f-pdf/f_ja01148a020.pdf}} == See also == *[[Erbium]] *[[Ytterbium]] *[[Yttrium]] == External links == {{Commons|Terbium}} {{wiktionary|terbium}} * [http://www.webelements.com/webelements/elements/text/Tb/index.html WebElements.com &ndash; Terbium] * [http://education.jlab.org/itselemental/ele065.html It's Elemental &ndash; Terbium] {{clear}} {{Compact periodic table}} [[Category:Chemical elements]] [[Category:Lanthanides]] <!-- interwiki --> [[ar:تيربيوم]] [[bn:টারবিয়াম]] [[be:Тэрбій]] [[bs:Terbijum]] [[ca:Terbi]] [[cs:Terbium]] [[co:Terbiu]] [[da:Terbium]] [[de:Terbium]] [[et:Terbium]] [[el:Τέρβιο]] [[es:Terbio]] [[eo:Terbio]] [[eu:Terbio]] [[fa:تربیوم]] [[fr:Terbium]] [[fur:Terbi]] [[gv:Çherbium]] [[gl:Terbio]] [[ko:터븀]] [[hy:Կերբիում]] [[hr:Terbij]] [[io:Terbio]] [[id:Terbium]] [[it:Terbio]] [[he:טרביום]] [[jv:Terbium]] [[la:Terbium]] [[lv:Terbijs]] [[lb:Terbium]] [[lt:Terbis]] [[jbo:jinmrterbi]] [[hu:Terbium]] [[ml:ടെര്‍ബിയം]] [[nl:Terbium]] [[ja:テルビウム]] [[no:Terbium]] [[nn:Terbium]] [[pl:Terb]] [[pt:Térbio]] [[ro:Terbiu]] [[ru:Тербий]] [[scn:Terbiu]] [[sk:Terbium]] [[sl:Terbij]] [[sr:Тербијум]] [[sh:Terbijum]] [[fi:Terbium]] [[sv:Terbium]] [[ta:டெர்பியம்]] [[th:เทอร์เบียม]] [[tr:Terbiyum]] [[uk:Тербій]] [[zh:铽]]