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{{infobox terbium}}
'''Terbium''' is a [[chemical element]]; it has [[Symbol (chemistry)|symbol]] '''Tb''' and [[atomic number]] 65. It is a silvery-white, [[rare earth element|rare earth]] [[metal]] that is [[malleable]] and [[ductile]]. The ninth member of the [[lanthanide]] series, terbium is a fairly [[electropositive]] metal that reacts with water, evolving [[hydrogen]] gas. Terbium is never found in nature as a free element, but it is contained in many [[mineral]]s, including [[cerite]], [[gadolinite]], [[monazite]], [[xenotime]] and [[euxenite]].

Swedish chemist [[Carl Gustaf Mosander]] discovered terbium as a chemical element in 1843. He detected it as an impurity in [[Yttrium(III) oxide|yttrium oxide]] ({{chem2|Y2O3}}). [[Yttrium]] and terbium, as well as [[erbium]] and [[ytterbium]], are named after the village of [[Ytterby]] in Sweden. Terbium was not isolated in pure form until the advent of [[ion exchange]] techniques.

Terbium is used to [[dopant|dope]] [[calcium fluoride]], calcium [[tungstate]] and [[strontium]] [[molybdate]] in [[solid-state device]]s, and as a crystal stabilizer of [[fuel cell]]s that operate at elevated temperatures. As a component of [[Terfenol-D]] (an alloy that expands and contracts when exposed to magnetic fields more than any other alloy), terbium is of use in [[actuator]]s, in naval [[sonar]] systems and in [[sensor]]s. Terbium is considered non-hazardous, though its biological role and toxicity have not been researched in depth.

Most of the world's terbium supply is used in green [[phosphor]]s. Terbium [[oxide]] is used in [[fluorescent lamp]]s and television and monitor [[cathode-ray tube]]s (CRTs). Terbium green phosphors are combined with divalent [[europium]] blue phosphors and trivalent europium red phosphors to provide [[trichromatic]] lighting technology, a high-efficiency white light used in indoor lighting.

== Characteristics ==

=== Physical properties ===
Terbium is a silvery-white [[rare earth element|rare earth]] [[metal]] that is [[malleable]], [[ductile]] and soft enough to be cut with a knife.<ref name="CRC" /> It is relatively stable in air compared to the more reactive lanthanides in the first half of the lanthanide series.<ref>{{cite web| url = http://www.elementsales.com/re_exp/index.htm |title = Rare-Earth Metal Long Term Air Exposure Test| access-date = 2009-05-05}}</ref> Terbium exists in two crystal [[allotropy|allotropes]] with a transformation temperature of 1289&nbsp;°C between them.<ref name="CRC" /> The 65 electrons of a terbium atom are arranged in the [[electron configuration]] [Xe]4f<sup>9</sup>6s<sup>2</sup>. The eleven 4f and 6s electrons are [[valence electron|valence]]. Only three electrons can be removed before the nuclear charge becomes too great to allow further ionization, but in the case of terbium, the stability of the half-filled [Xe]4f<sup>7</sup> configuration allows further ionization of a fourth electron in the presence of very strong oxidizing agents such as [[fluorine]] gas.<ref name="CRC" />

The terbium(III) cation (Tb<sup>3+</sup>) is brilliantly [[Fluorescence|fluorescent]], in a 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. Terbium easily oxidizes, and is therefore used in its elemental form specifically for research. Single terbium atoms have been isolated by implanting them into [[fullerene]] molecules. Trivalent [[europium]] (Eu<sup>3+</sup>) and Tb<sup>3+</sup> ions are among the lanthanide ions that have garnered the most attention because of their strong luminosity and great color purity.<ref>V.B. Taxak, R. Kumar, J.K. Makrandi, S.P. Khatkar Displays, 30 (2009), pp. 170–174</ref><ref>{{cite journal|last1=Shimada|first1=T.|last2=Ohno|first2=Y.|last3=Okazaki|first3=T.|last4=Sugai|first4=T.|last5=Suenaga|first5=K.|last6=Kishimoto|first6=S.|last7=Mizutani|first7=T.|last8=Inoue|first8=T.|last9=Taniguchi|first9=R.|last10=Fukui|display-authors=3 | first10=N.|last11=Okubo | first11=H.|last12=Shinohara | first12=H.|title=Transport properties of C<sub>78</sub>, C<sub>90</sub> and Dy@C<sub>82</sub> fullerenes – nanopeapods by field effect transistors|journal=Physica E: Low-dimensional Systems and Nanostructures|year=2004|volume=21|issue=2–4|pages=1089–1092|doi=10.1016/j.physe.2003.11.197|bibcode = 2004PhyE...21.1089S}}</ref>

Terbium has a simple [[ferromagnetic]] ordering at temperatures below 219&nbsp;K. Above 219&nbsp;K, it turns into a [[Helimagnetism|helical antiferromagnetic]] state in which all of the atomic moments in a particular [[basal plane]] layer are parallel and oriented at a fixed angle to the moments of adjacent layers. This antiferromagnetism transforms into a disordered [[paramagnetic]] state at 230&nbsp;K.<ref>{{cite journal| author =Jackson, M. | title =Magnetism of Rare Earth| url =http://www.irm.umn.edu/quarterly/irmq10-3.pdf | journal = The IRM Quarterly | volume =10| issue = 3| page = 1| date = 2000}}</ref>

=== Chemical properties ===
Terbium metal is an electropositive element and oxidizes in the presence of most acids (such as sulfuric acid), all of the halogens, and water.<ref name="reactions" />
:{{chem2|2 Tb (s) + 3 H2SO4 → 2 Tb(3+) + 3 SO4(2-) + 3 H2↑}}
:{{chem2|1=2 Tb + 3 X2 → 2 TbX3 (X = [[fluorine|F]], [[chlorine|Cl]], [[bromine|Br]], [[iodine|I]])}}
:{{chem2|2 Tb (s) + 6 H2O → 2 Tb(OH)3 + 3 H2↑}}
Terbium oxidizes readily in air to form a mixed [[terbium(III,IV) oxide]]:<ref name="reactions">{{cite web| url =https://www.webelements.com/terbium/chemistry.html| title =Chemical reactions of Terbium| publisher=Webelements| access-date=2009-06-06}}</ref>
:{{chem2|8 Tb + 7 O2 → 2 Tb4O7}}

The most common oxidation state of terbium is +3 (trivalent), such as in [[Terbium trichloride|{{chem|Tb||Cl|3}}]]. In the solid state, tetravalent terbium is also known, in compounds such as terbium oxide ({{chem2|TbO2}}) and terbium tetrafluoride.<ref>{{cite journal|title=Higher Oxides of the Lanthanide Elements: Terbium Dioxide|author=Gruen, D. M. |author2=Koehler, W. C. |author3=Katz, J. J. |date=April 1951|pages=1475–1479|volume=73|journal=Journal of the American Chemical Society|doi=10.1021/ja01148a020|issue=4|bibcode=1951JAChS..73.1475G }}</ref> In solution, terbium typically forms trivalent species, but can be oxidized to the tetravalent state with [[ozone]] in highly basic aqueous conditions.<ref>{{cite journal |title=Stabilization of Praseodymium(IV) and Terbium(IV) in Aqueous Carbonate Solution |author1=Hobart, D. E. |author2= Samhoun, K. |author3= Young, J. P. |author4=Norvell, V. E. |author5= Mamantov, G. |author6= Peterson, J. R. |date=1980 |pages=321–328 |volume=16 |journal=Inorganic and Nuclear Chemistry Letters |doi=10.1016/0020-1650(80)80069-9 |issue=5}}</ref>

The coordination and organometallic chemistry of terbium is similar to other lanthanides. In aqueous conditions, terbium can be coordinated by nine [[water]] molecules, which are arranged in a [[tricapped trigonal prismatic molecular geometry]].<ref>{{Cite journal |last1=Zhuang |first1=Jia-Jia |last2=Chen |first2=Ming-Guang |last3=Sun |first3=Yan-Bing |last4=Hang |first4=Pei |last5=Sui |first5=Yang |last6=Tong |first6=Jia-Ping |date=2020-03-01 |title=Synthesis, Structure and Magnetic Property of a Tricapped Trigonal Prismatic Tb<sup>III</sup>-Based 3d-4f Complex |journal=IOP Conference Series: Materials Science and Engineering |volume=774 |issue=1 |pages=012042 |doi=10.1088/1757-899X/774/1/012042 |issn=1757-8981|doi-access=free |bibcode=2020MS&E..774a2042Z }}</ref> Complexes of terbium with lower coordination number are also known, typically with bulky ligands like [[Metal bis(trimethylsilyl)amides|bis(trimethylsilyl)amide]], which forms the three-coordinate tris[N,N-bis(trimethylsilyl)amide]terbium(III) ({{chem2|Tb[N(SiMe3)2]3}}) complex.<ref>{{Cite journal |last1=Boyde |first1=Nicholas C. |last2=Chmely |first2=Stephen C. |last3=Hanusa |first3=Timothy P. |last4=Rheingold |first4=Arnold L. |last5=Brennessel |first5=William W. |date=2014-09-15 |title=Structural Distortions in M[E(SiMe<sub>3</sub>)<sub>2</sub>]<sub>3</sub> Complexes (M = Group 15, f-Element; E = N, CH): Is Three a Crowd? |url=https://pubs.acs.org/doi/10.1021/ic501232z |journal=Inorganic Chemistry |language=en |volume=53 |issue=18 |pages=9703–9714 |doi=10.1021/ic501232z |pmid=25171144 |issn=0020-1669|url-access=subscription }}</ref>

Most coordination and organometallic complexes contain terbium in the trivalent oxidation state. Divalent Tb<sup>2+</sup> complexes are also known, usually with bulky [[Cyclopentadienyl complex|cyclopentadienyl-type ligands]].<ref>{{cite journal |title=Tetramethylcyclopentadienyl Ligands Allow Isolation of Ln(II) Ions across the Lanthanide Series in [K(2.2.2-cryptand)][(C<sub>5</sub>Me<sub>4</sub>H)<sub>3</sub>Ln] Complexes |author1=Jenkins, T. F. |author2= Woen, D. H |author3= Mohanam, L. N. |author4=Ziller, J. W. |author5=Furche, F. |author6=Evans, W. J. |date=2018|pages=3863–3873|volume=141 |journal=Organometallics |doi=10.1021/acs.organomet.8b00557 |issue=21|s2cid=105379627 }}</ref><ref>{{cite journal |title=Completing the Series of +2 Ions for the Lanthanide Elements: Synthesis of Molecular Complexes of Pr<sup>2+</sup>, Gd<sup>2+</sup>, Tb<sup>2+</sup>, and Lu<sup>2+</sup> |author1=Macdonald, M. R. |author2= Bates, J. E. |author3= Ziller, J. W. |author4=Furche, F. |author5=Evans, W. J. |date=2013|pages=9857–9868|volume=135|journal=Journal of the American Chemical Society|doi=10.1021/ja403753j|issue=21|pmid=23697603 |bibcode=2013JAChS.135.9857M }}</ref><ref>{{Cite journal|last1=Gould|first1=C. A.|last2=McClain|first2=K. R. |last3=Yu|first3=J. M.|last4=Groshens|first4=T. J.|last5=Furche|first5=F. P.|last6=Harvey|first6=B. G.|last7=Long|first7=J. R.|date=2019-08-21|title=Synthesis and Magnetism of Neutral, Linear Metallocene Complexes of Terbium(II) and Dysprosium(II)|journal=Journal of the American Chemical Society|volume=141|issue=33|pages=12967–12973|doi=10.1021/jacs.9b05816|pmid=31375028|bibcode=2019JAChS.14112967G |s2cid=199388151|issn=0002-7863}}</ref> A few coordination compounds containing terbium in its tetravalent state are also known.<ref>{{cite journal |title=Molecular Complex of Tb in the +4 Oxidation State |author1=Palumbo, C. T. |author2=Zivkovic, I. |author3=Scopelliti, R. |author4=Mazzanti, M. |date=2019 |pages=9827–9831 |volume=141 |journal=Journal of the American Chemical Society |doi=10.1021/jacs.9b05337 |pmid=31194529 |issue=25 |bibcode=2019JAChS.141.9827P |s2cid=189814301 |url=http://infoscience.epfl.ch/record/268286/files/Palumbo%20ja-2019-05337d%20manuscriptR1.pdf |archive-url=https://web.archive.org/web/20240423040613/https://infoscience.epfl.ch/record/268286/files/Palumbo%20ja-2019-05337d%20manuscriptR1.pdf |url-status=dead |archive-date=April 23, 2024 }}</ref><ref>{{Cite journal|last1=Rice|first1=N. T.|last2=Popov|first2=I. A.|last3=Russo|first3=D. R.|last4=Bacsa|first4=J.|last5=Batista|first5=E. R.|last6=Yang|first6=P.|last7=Telser|first7=J.|last8=La Pierre|first8=H. S.|date=2019-08-21|title=Design, Isolation, and Spectroscopic Analysis of a Tetravalent Terbium Complex|journal=Journal of the American Chemical Society|volume=141|issue=33|pages=13222–13233|doi=10.1021/jacs.9b06622|pmid=31352780|bibcode=2019JAChS.14113222R |osti=1558225|s2cid=207197096|issn=0002-7863|url=https://figshare.com/articles/journal_contribution/9450461 }}</ref><ref>{{cite journal |title= Stabilization of the Oxidation State +IV in Siloxide-Supported Terbium Compounds |author1=Willauer, A. R. |author2=Palumbo, C. T. |author3=Scopelliti, R. |author4=Zivkovic, I. |author5=Douair, I. |author6=Maron, L.  |author7=Mazzanti, M. |date=2020 |pages=3549–3553|volume=59 |journal=Angewandte Chemie International Edition |issue=9 |doi=10.1002/anie.201914733|pmid=31840371 |s2cid=209385870 |url=https://infoscience.epfl.ch/record/275738/files/Mazzanti_et_al-2019-Angewandte_Chemie_International_Edition-2.pdf }}</ref>

==== Oxidation states ====
Like most [[rare-earth elements]] and [[lanthanides]], terbium is usually found in the +3 oxidation state. Like [[cerium]] and [[praseodymium]], terbium can also form a +4 oxidation state,<ref name=":1">{{Cite journal |last1=Palumbo |first1=Chad T. |last2=Zivkovic |first2=Ivica |last3=Scopelliti |first3=Rosario |last4=Mazzanti |first4=Marinella |date=2019-06-26 |title=Molecular Complex of Tb in the +4 Oxidation State |url=https://pubs.acs.org/doi/10.1021/jacs.9b05337 |journal=Journal of the American Chemical Society |language=en |volume=141 |issue=25 |pages=9827–9831 |doi=10.1021/jacs.9b05337 |pmid=31194529 |bibcode=2019JAChS.141.9827P |issn=0002-7863}}</ref> although it is unstable in water.<ref>{{Greenwood&Earnshaw2nd}}</ref> It is possible for terbium to be found in the 0,<ref name="Cloke">{{cite journal |last=Cloke |first=F. Geoffrey N. |date=1993 |title=Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides |journal=Chem. Soc. Rev. |volume=22 |pages=17–24 |doi=10.1039/CS9932200017}}</ref><ref name="Arnold">{{cite journal |last1=Arnold |first1=Polly L. |last2=Petrukhina |first2=Marina A. |last3=Bochenkov |first3=Vladimir E. |last4=Shabatina |first4=Tatyana I. |last5=Zagorskii |first5=Vyacheslav V. |last6=Cloke |first9=F. Geoffrey N. |date=2003-12-15 |title=Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation |journal=Journal of Organometallic Chemistry |volume=688 |issue=1–2 |pages=49–55 |doi=10.1016/j.jorganchem.2003.08.028}}</ref> +1,<ref name="Wan-Lu Li">{{cite journal |last1=Li |first1=Wan-Lu |last2=Chen |first2=Teng-Teng |last3=Chen |first3=Wei-Jia |last4=Li |first4=Jun |last5=Wang |first5=Lai-Sheng |year=2021 |title=Monovalent lanthanide(I) in borozene complexes |journal=Nature Communications |volume=12 |issue=1 |page=6467 |bibcode=2021NatCo..12.6467L |doi=10.1038/s41467-021-26785-9 |pmc=8578558 |pmid=34753931}}</ref> and +2<ref name=":1" /> oxidation states.

=== Compounds ===
{{Main article|Terbium compounds}}
{{multiple image | direction = vertical | width = 200
|align=right
|image1=Tb-sulfate.jpg
|image2=Tb-sulfate-luminescence.jpg
|caption2=Terbium sulfate, {{chem2|Tb2(SO4)3}} (top), fluoresces green under ultraviolet light (bottom)}}

Terbium combines with nitrogen, carbon, sulfur, phosphorus, boron, selenium, silicon and arsenic at elevated temperatures, forming various binary compounds such as {{chem2|TbH2}}, {{chem2|TbH3}}, {{chem2|TbB2}}, {{chem2|TbSi2|link=Terbium silicide}}, {{chem2|TbN|link=Terbium(III) nitride}}, {{chem2|TbP|link=Terbium phosphide}}, {{chem2|TbS|link=Terbium monosulfide}}, {{chem2|Tb2S3}}, {{chem2|TbSe}}, and {{chem2|TbTe}}.<ref name="patnaik" /> In these compounds, terbium mainly exhibits the oxidation state +3, with the +2 state appearing rarely. Terbium(II) halides are obtained by [[annealing (materials science)|annealing]] terbium(III) halides in presence of metallic terbium in [[tantalum]] containers. Terbium also forms the sesquichloride {{chem2|Tb2Cl3}}, which can be further reduced to terbium(I) chloride ({{Chem2|TbCl}}) by annealing at 800&nbsp;°C; this compound forms platelets with layered graphite-like structure.<ref>{{cite book| page=1128| url=https://books.google.com/books?id=U3MWRONWAmMC&pg=PA1128| title =Advanced inorganic chemistry| edition =6th| author= Cotton| publisher= Wiley-India| date = 2007| isbn =978-81-265-1338-3}}</ref>

[[Terbium(IV) fluoride]] ({{Chem2|TbF4}}) is the only halide that tetravalent terbium can form. It has strong oxidizing properties and is a strong [[halogenation|fluorinating agent]], emitting relatively pure atomic [[fluorine]] when heated, rather than the mixture of fluoride vapors emitted from [[cobalt(III) fluoride]] or [[cerium(IV) fluoride]].<ref>{{cite journal |last1=Rau |first1=J. V. |last2=Chilingarov |first2=N. S. |last3=Leskiv |first3=M. S. |last4=Sukhoverkhov |first4=V. F. |last5=Rossi Albertini |first5=V. |last6=Sidorov |first6=L. N. |title=Transition and rare earth metal fluorides as thermal sources of atomic and molecular fluorine |journal=Le Journal de Physique IV |date=August 2001 |volume=11 |issue=PR3 |pages=Pr3–109–Pr3-113 |doi=10.1051/jp4:2001314}}</ref> It can be obtained by reacting [[terbium(III) chloride]] or [[terbium(III) fluoride]] with [[fluorine]] gas at 320&nbsp;°C:<ref>{{Cite book|author=G. Meyer |author2=Lester R. Morss |title= Synthesis of Lanthanide and Actinide Compounds |publisher=Springer Science & Business Media|year= 1991|page=60|isbn= 978-0-7923-1018-1 |url = https://books.google.com/books?id=bnS5elHL2w8C&pg=PA60}}</ref>
: 2 TbF<sub>3</sub> + F<sub>2</sub> → 2 TbF<sub>4</sub>
When {{Chem2|TbF4}} and [[caesium fluoride]] (CsF) is mixed in a stoichiometric ratio in a fluorine gas atmosphere, caesium pentafluoroterbate ({{Chem2|CsTbF5}}) is obtained. It is an [[orthorhombic crystal system|orthorhombic]] crystal with [[space group]] ''Cmca'' and a layered structure composed of [TbF<sub>8</sub>]<sup>4−</sup> and 11-coordinated Cs<sup>+</sup>.<ref>{{cite journal|last1=Gaumet|first1=V.|last2=Avignant|first2=D.|title=Caesium Pentafluoroterbate, CsTbF<sub>5</sub>|journal=Acta Crystallographica Section C: Crystal Structure Communications|volume=53|issue=9|year=1997|pages=1176–1178 |doi=10.1107/S0108270197005556|bibcode=1997AcCrC..53.1176G }}</ref> The compound barium hexafluoroterbate ({{Chem2|BaTbF6}}), an orthorhombic crystal with space group ''Cmma'', can be prepared in a similar method. The terbium fluoride ion [TbF<sub>8</sub>]<sup>4−</sup><ref>{{cite journal|last1=Largeau|first1=E.|last2=El-Ghozzi|first2=M.|last3=Métin|first3=J.|last4=Avignant|first4=D.|title=β-BaTbF6|journal=Acta Crystallographica Section C: Crystal Structure Communications|volume=53|issue=5|year=1997|pages=530–532 |doi=10.1107/S0108270196014527|bibcode=1997AcCrC..53..530L }}</ref> also exists in the structure of potassium terbium fluoride crystals.<ref>{{Cite journal |last1=Balodhi |first1=Ashiwini |last2=Chang |first2=Kelvin |last3=Stevens |first3=Kevin T. |last4=Chakrapani |first4=Sunil K. |last5=Ennaceur |first5=Susan M. |last6=Migliori |first6=Albert |last7=Zevalkink |first7=Alexandra |date=2020-10-26 |title=Determination of single crystal elastic moduli of KTb<sub>3</sub>F<sub>10</sub> by resonant ultrasound spectroscopy |url=https://pubs.aip.org/aip/jap/article/128/16/165104/568450/Determination-of-single-crystal-elastic-moduli-of |journal=Journal of Applied Physics |volume=128 |issue=16 |doi=10.1063/5.0024723 |bibcode=2020JAP...128p5104B |issn=0021-8979}}</ref><ref>{{Cite journal |last1=Valiev |first1=Uygun V. |last2=Karimov |first2=Denis N. |last3=Ma |first3=Chong-Geng |last4=Sultonov |first4=Odiljon Z. |last5=Pelenovich |first5=Vasiliy O. |date=2022-11-12 |title=Tb<sup>3+</sup> Ion Optical and Magneto-Optical Properties in the Cubic Crystals KTb<sub>3</sub>F<sub>10</sub> |journal=Materials |language=en |volume=15 |issue=22 |pages=7999 |doi=10.3390/ma15227999 |issn=1996-1944 |pmc=9693278 |pmid=36431487 |doi-access=free|bibcode=2022Mate...15.7999V }}</ref>

[[Terbium(III) oxide]] or terbia is the main oxide of terbium, and appears as a dark brown water-insoluble solid. It is slightly hygroscopic<ref name=":02">{{Cite book |last1=Larrañaga |first1=Michael D. |url=https://onlinelibrary.wiley.com/doi/book/10.1002/9781119312468 |title=Hawley's Condensed Chemical Dictionary |last2=Lewis |first2=Richard J. |last3=Lewis |first3=Robert A. |date=September 2016 |publisher=Wiley |isbn=978-1-118-13515-0 |edition=16th |pages=1310 |language=en |doi=10.1002/9781119312468}}</ref> and is the main terbium compound found in rare earth-containing minerals and clays.<ref name=":2" />

Other compounds include: 
* [[Chloride]]s: {{chem2|[[terbium(III) chloride|TbCl3]]}}
* [[Bromide]]s: {{chem2|[[terbium(III) bromide|TbBr3]]}}
* [[Iodide]]s: {{chem2|[[terbium(III) iodide|TbI3]]}}
* [[Fluoride]]s: {{chem2|[[terbium(III) fluoride|TbF3]]}}, {{chem2|[[terbium(IV) fluoride|TbF4]]}}

=== Isotopes ===
{{Main|Isotopes of terbium}}
Naturally occurring terbium is composed of its only stable [[isotope]], terbium-159; the element is thus [[mononuclidic element|mononuclidic]] and [[monoisotopic element|monoisotopic]].<ref name="CIAAWterbium"/> Thirty-nine [[radioisotope]]s have been characterized,{{AME2020 II|ref}} with the heaviest being terbium-174 and lightest being terbium-135 (both with unknown exact mass).{{NUBASE2020|ref}} The most stable [[synthetic radioisotope]]s of terbium are terbium-158, with a [[half-life]] of 180 years, and terbium-157, with a half-life of 71 years. All of the remaining [[radioactive]] isotopes have half-lives that are less than three months, and the majority of these have half-lives that are less than half a minute.{{NUBASE2020|ref}} The primary [[decay mode]] before the most abundant stable isotope, {{sup|159}}Tb, is [[electron capture]], which results in production of [[gadolinium]] isotopes, and the primary mode after is [[beta minus decay]], resulting in [[dysprosium]] isotopes.{{NUBASE2020|ref}}

The element also has 31 [[nuclear isomer]]s, with masses of 141–154, 156, 158, 162, and 164–168 (not every mass number corresponds to only one isomer).{{AME2020 II|ref}} The most stable of them are terbium-156m, with a half-life of 24.4 hours, and terbium-156m2, with a half-life of 22.7 hours; this is longer than half-lives of most ground states of radioactive terbium isotopes, except those with mass numbers 155–161.{{NUBASE2020|ref}}

Terbium-149, with a half-life of 4.1 hours, is a promising candidate in [[targeted alpha therapy]] and [[positron emission tomography]].<ref>{{cite journal | last1=Müller | first1=Cristina | last2=Vermeulen | first2=Christiaan | last3=Köster | first3=Ulli | last4=Johnston | first4=Karl | last5=Türler | first5=Andreas | last6=Schibli | first6=Roger | last7=van der Meulen | first7=Nicholas P. | title=Alpha-PET with terbium-149: evidence and perspectives for radiotheragnostics | journal=EJNMMI Radiopharmacy and Chemistry | publisher=Springer Science and Business Media LLC | volume=1 | issue=1 | date=2016-03-28 | page=5 | issn=2365-421X | doi=10.1186/s41181-016-0008-2| pmid=29564382 | pmc=5843804 | doi-access=free }}</ref><ref>{{cite journal | last1=Eychenne | first1=Romain | last2=Chérel | first2=Michel | last3=Haddad | first3=Férid | last4=Guérard | first4=François | last5=Gestin | first5=Jean-François | title=Overview of the Most Promising Radionuclides for Targeted Alpha Therapy: The "Hopeful Eight" | journal=Pharmaceutics | publisher=MDPI AG | volume=13 | issue=6 | date=2021-06-18 | issn=1999-4923 | doi=10.3390/pharmaceutics13060906 | page=906 | pmid=34207408 | pmc=8234975 | doi-access=free }}</ref>

== History ==
[[File:Mosander Carl Gustav bw.jpg|thumb|right|[[Carl Gustaf Mosander]], the scientist who discovered terbium, lanthanum and erbium]]
[[Sweden|Swedish]] [[chemist]] [[Carl Gustaf Mosander]] discovered terbium in 1843.<ref name="Beginnings">{{cite journal |last1=Marshall |first1=James L. Marshall |last2=Marshall |first2=Virginia R. Marshall |title=Rediscovery of the elements: The Rare Earths–The Beginnings |journal=The Hexagon |date=2015 |pages=41–45 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20I.pdf |access-date=30 December 2019}}</ref><ref name="Virginia">{{cite journal |last1=Marshall |first1=James L. Marshall |last2=Marshall |first2=Virginia R. Marshall |title=Rediscovery of the elements: The Rare Earths–The Confusing Years |journal=The Hexagon |date=2015 |pages=72–77 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20II.pdf |access-date=30 December 2019}}</ref> He detected it as an impurity in [[yttrium oxide]], {{chem2|Y2O3}}, then known as yttria. Yttrium, erbium, and terbium are all named after the village of [[Ytterby]] in [[Sweden]].<ref name="XVI">{{Unbulleted list citebundle|{{cite journal | author = Weeks, Mary Elvira |author-link=Mary Elvira Weeks| title = The discovery of the elements: XVI. The rare earth elements | journal = Journal of Chemical Education | year = 1932 | volume = 9 | issue = 10 | pages = 1751&ndash;1773 | doi = 10.1021/ed009p1751 | bibcode=1932JChEd...9.1751W}}|{{cite book |last1=Weeks |first1=Mary Elvira |url=https://archive.org/details/discoveryoftheel002045mbp |title=The discovery of the elements |date=1956 |publisher=Journal of Chemical Education |edition=6th |location=Easton, PA |pages=705–706}}}}</ref><ref name="James">{{cite book |last1=Marshall |first1=James L. |title=Science history: a traveler's guide |last2=Marshall |first2=Virginia R. |date=October 31, 2014 |publisher=ACS Symposium Series |isbn=978-0-8412-3020-0 |volume=1179 |pages=209–257 |chapter=Northern Scandinavia: An Elemental Treasure Trove |doi=10.1021/bk-2014-1179.ch011}}</ref> Terbium was not isolated in pure form until the advent of [[ion exchange]] techniques.<ref name="history">{{cite book |author=Gupta, C. K. |url=https://books.google.com/books?id=E1npz8pwmYwC&pg=PA5 |title=Extractive metallurgy of rare earths |author2=Krishnamurthy, Nagaiyar |date=2004 |publisher=CRC Press |isbn=978-0-415-33340-5 |page=5}}</ref>

Mosander first separated yttria into three fractions, all named for the ore: yttria, erbia, and terbia. "Terbia" was originally the fraction that contained the pink color, due to the element now known as [[erbium]]. "Erbia", the oxide containing what is now known as terbium, originally was the fraction that was yellow or dark orange in solution.<ref name="Beginnings" /><ref name="XVI" /> The insoluble oxide of this element was noted to be tinged brown,<ref>{{Cite journal|url=https://adsabs.harvard.edu/full/1906ApJ....24..309E |journal=Astrophysical Journal |volume=24 |page=309 |date=1906 |first1=G. |last1=Eberhard |title=A Spectroscopic Investigation of Dr. G. Urbain's Preparations of Terbium |issue=5|doi=10.1086/141398 |bibcode=1906ApJ....24..309E }}</ref><ref>{{Cite journal |last1=Stubblefield |first1=C. T. |last2=Eick |first2=H. |last3=Eyring |first3=L. |date=August 1956 |title=Terbium Oxides. II. The Heats of Formation of Several Oxides 1 |url=https://pubs.acs.org/doi/abs/10.1021/ja01597a005 |journal=Journal of the American Chemical Society |language=en |volume=78 |issue=16 |pages=3877–3879 |doi=10.1021/ja01597a005 |bibcode=1956JAChS..78.3877S |issn=0002-7863|url-access=subscription }}</ref><ref name=":02" /> and soluble oxides after combustion were noted to be colorless.<ref name=":0">{{Cite book |last=Watts |first=Henry |url=https://books.google.com/books?id=sYEPAQAAIAAJ&dq=terbium+sulfates+discovery&pg=PA2155 |title=A Dictionary of Chemistry and the Allied Branches of Other Sciences |date=1881 |publisher=Longmans, Green, and Company |pages=2155 |language=en}}</ref> Until the advent of spectral analysis, arguments went back and forth as to whether erbia even existed. Spectral analysis by [[Marc Delafontaine]] allowed the separate elements and their oxides to be identified,<ref name="history" /> but in his publications, the names of erbium and terbium were switched,{{Sfn|Voncken|2016|p=10-11}} following a brief period where terbium was renamed "mosandrum", after Mosander.<ref>{{Cite journal |last=Holden |first=Norman E. |date=March 12, 2004 |orig-date=July 8th, 2001 |title=History of the Origin of the Chemical Elements and Their Discoverers |url=https://www.nndc.bnl.gov/content/elements.html |journal=41st IUPAC General Assembly in Brisbane, Australia}}</ref> The names have remained switched ever since.<ref name="XVI" />

The early years of preparing terbium (as terbium oxide) were difficult. Metal oxides from [[gadolinite]] and [[Samarskite-(Y)|samarskite]] were dissolved in [[nitric acid]], and the solution was further separated using [[oxalic acid]] and [[potassium sulfate]]. There was great difficulty in separating erbia from terbia; in 1881, it was noted that there was no satisfactory method to separate the two.<ref name=":0" /> By 1914, different solvents had been used to separate terbium from its host minerals, but the process of separating terbium from its neighbor elements - [[gadolinium]] and [[dysprosium]] - was described as "tedious" but possible.<ref>{{Cite journal |last1=James |first1=C. |url=https://books.google.com/books?id=Yf_yAAAAMAAJ |journal=Journal of the American Chemical Society |last2=Bissel |first2=D. W. |date=June 4, 1914 |publisher=American Chemical Society |pages=2062 |language=en |title=Terbium}}</ref> Modern terbium extraction methods are based on the [[liquid–liquid extraction]] process developed by Werner Fischer et al., in 1937.<ref>{{Cite book |last1=Bünzli |first1=Jean-Claude G. |url=https://onlinelibrary.wiley.com/doi/book/10.1002/14356007 |title=Ullmann's Encyclopedia of Industrial Chemistry |last2=Mcgill |first2=Ian |date=2003-03-11 |publisher=Wiley |isbn=978-3-527-30385-4 |edition=1 |language=en |chapter=Rare Earth Elements |doi=10.1002/14356007.a22_607.pub2}}</ref>

== Occurrence ==
[[Image:Xenotim mineralogisches museum bonn.jpg|thumb|Xenotime, a mineral source of rare earth elements including terbium|alt=A sample of the mineral xenotime at the Mineralogical Museum, Bonn, Germany]]
Terbium occurs with other rare earth elements in many minerals, including monazite ({{chem2|(Ce,La,Th,Nd,Y)PO4}} with up to 0.03% terbium), [[xenotime]] ({{chem2|YPO4}}) and [[euxenite]] ({{chem2|(Y,Ca,Er,La,Ce,U,Th)(Nb,Ta,Ti)2O6}} with 1% or more terbium). The crust abundance of terbium is estimated as 1.2&nbsp;mg/kg.<ref name="patnaik">{{cite book | last =Patnaik | first =Pradyot | date = 2003 | title =Handbook of Inorganic Chemical Compounds | publisher = McGraw-Hill | pages = 920–921| isbn =978-0-07-049439-8 | url= https://books.google.com/books?id=Xqj-TTzkvTEC&pg=PA243 | access-date = 2009-06-06}}</ref> No terbium-dominant mineral has yet been found.<ref>{{Cite journal |last=Attia |first=Yosry A. |date=October 1990 |title=Extraction and Refining of High Purity Terbium Metal From Rare Earth Resources |url=http://www.tandfonline.com/doi/abs/10.1080/08827509008952668 |journal=Mineral Processing and Extractive Metallurgy Review |language=en |volume=7 |issue=2 |pages=95–114 |doi=10.1080/08827509008952668 |bibcode=1990MPEMR...7...95A |issn=0882-7508|url-access=subscription }}</ref>

Terbium (as the species Tb [[Spectroscopic notation|II]]) has been detected in the atmosphere of [[KELT-9b]], a hot-Jupiter [[exoplanet|planet outside the Solar System]].<ref>{{Cite journal |last1=Borsato |first1=N. W. |last2=Hoeijmakers |first2=H. J. |last3=Prinoth |first3=B. |last4=Thorsbro |first4=B. |last5=Forsberg |first5=R. |last6=Kitzmann |first6=D. |last7=Jones |first7=K. |last8=Heng |first8=K. |date=May 2023 |title=The Mantis Network: III. Expanding the limits of chemical searches within ultra-hot Jupiters: New detections of Ca I, V I, Ti I, Cr I, Ni I, Sr II, Ba II, and Tb II in KELT-9 b |url=https://www.aanda.org/10.1051/0004-6361/202245121 |journal=Astronomy & Astrophysics |volume=673 |pages=A158 |arxiv=2304.04285 |doi=10.1051/0004-6361/202245121 |bibcode=2023A&A...673A.158B |issn=0004-6361}}</ref>

Currently, the richest commercial sources of terbium are the ion-adsorption [[clay]]s of [[southern China]];<ref name=":2" /> the concentrates with about two-thirds yttrium oxide by weight have about 1% terbia. Small amounts of terbium occur in bastnäsite and monazite; when these are processed by solvent extraction to recover the valuable heavy lanthanides as [[samarium]]-[[europium]]-[[gadolinium]] concentrate, terbium is recovered therein. Due to the large volumes of bastnäsite processed relative to the ion-adsorption clays, a significant proportion of the world's terbium supply comes from bastnäsite.<ref name="CRC" />

In 2018, a rich terbium supply was discovered off the coast of [[Japan]]'s [[Minamitori Island]], with the stated supply being "enough to meet the global demand for 420 years".<ref name="Takaya Yasukawa Kawasaki Fujinaga 2018 p.">{{cite journal | last1=Takaya | first1=Yutaro | last2=Yasukawa | first2=Kazutaka | last3=Kawasaki | first3=Takehiro | display-authors=etal | title=The tremendous potential of deep-sea mud as a source of rare-earth elements | journal=Scientific Reports | volume=8 | issue=1 | date=2018-04-10 | issn=2045-2322 | doi=10.1038/s41598-018-23948-5 | page=5763| pmid=29636486 | pmc=5893572 | bibcode=2018NatSR...8.5763T }}</ref>

== Production ==
Crushed terbium-containing minerals are treated with hot concentrated [[sulfuric acid]] to produce water-soluble sulfates of rare earths. The acidic filtrates are partially neutralized with caustic soda to pH 3–4. [[Thorium]] precipitates out of solution as hydroxide and is removed. The solution is treated with [[ammonium oxalate]] to convert rare earths into their insoluble [[oxalate]]s. The oxalates are decomposed to oxides by heating. The oxides are dissolved in [[nitric acid]] that excludes one of the main components, cerium, whose oxide is insoluble in {{chem2|HNO3}}. Terbium is separated as a [[double salt]] with [[ammonium nitrate]] by crystallization.<ref name="patnaik" />

The most efficient separation routine for terbium salt from the rare-earth salt solution is [[ion exchange]]. In this process, rare-earth ions are [[adsorption|sorbed]] onto suitable ion-exchange resin by exchange with hydrogen, ammonium or cupric ions present in the resin. The rare earth ions are then selectively washed out by suitable [[Complexing agent|complexing agents]]. As with other rare earths, terbium metal is produced by reducing the anhydrous chloride or fluoride with calcium metal. Calcium and [[tantalum]] impurities can be removed by vacuum remelting, distillation, amalgam formation or [[zone melting]].<ref name="patnaik" /><ref name="history" />

In 2020, the annual demand for terbium was estimated at {{Convert|340|t|lb}}.<ref name=":2">{{Cite journal |last1=Gao |first1=Cuixia |last2=Xu |first2=Yufei |last3=Geng |first3=Yong |last4=Xiao |first4=Shijiang |date=2022-12-01 |title=Uncovering terbium metabolism in China: A dynamic material flow analysis |url=https://linkinghub.elsevier.com/retrieve/pii/S0301420722004603 |journal=Resources Policy |volume=79 |pages=103017 |doi=10.1016/j.resourpol.2022.103017 |bibcode=2022RePol..7903017G |issn=0301-4207|url-access=subscription }}</ref> Terbium is not distinguished from other rare earths in the [[United States Geological Survey]]'s Mineral Commodity Summaries, which in 2024 estimated the global reserves of rare earth minerals at {{Convert|110000000|t|lb}}.<ref>{{Cite journal |date=January 2024 |title=Rare Earths |url=https://pubs.usgs.gov/periodicals/mcs2024/mcs2024-rare-earths.pdf |journal=Mineral Commodity Summaries |pages=144–145 |via=U. S. Geological Survey}}</ref>

== Applications ==
Terbium is used as a [[dopant]] in [[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 dioxide]] ({{chem2|ZrO2}}).<ref name="CRC">{{cite book | editor = Lide, D. R. | title = CRC Handbook of Chemistry and Physics | edition = 86th | location = Boca Raton (FL) | publisher = CRC Press | year = 2005 | isbn = 978-0-8493-0486-6 |author=Hammond, C. R. |chapter=The Elements}}</ref>{{Sfn|Voncken|2016|p=101}}

Terbium is also used in [[alloy]]s and in the production of electronic devices. As a component of [[Terfenol-D]], terbium is used in [[actuator]]s, in naval [[sonar]] systems, [[sensor]]s, and other magnetomechanical devices. Terfenol-D is a terbium alloy that expands or contracts in the presence of a magnetic field.<ref>{{Cite journal |last=Deng |first=Geng |date=January 2018 |title=Terbium glows green |url=https://www.nature.com/articles/nchem.2914 |journal=Nature Chemistry |language=en |volume=10 |issue=1 |pages=110 |doi=10.1038/nchem.2914 |pmid=29256517 |bibcode=2018NatCh..10..110D |issn=1755-4349}}</ref> It has the highest [[magnetostriction]] of any [[alloy]].<ref>{{cite journal|doi=10.1016/j.sna.2008.11.026|title=New elastomer–Terfenol-D magnetostrictive composites|date=2009|author=Rodriguez, C|journal=Sensors and Actuators A: Physical|volume=149|page=251|last2=Rodriguez|first2=M.|last3=Orue|first3=I.|last4=Vilas|first4=J.|last5=Barandiaran|first5=J.|last6=Gubieda|first6=M.|last7=Leon|first7=L.|issue=2|bibcode=2009SeAcA.149..251R }}</ref> It is used to increase verdet constant in long-distance fiber optic communication.<ref>{{cite web |url=https://www.stanfordmaterials.com/blog/terbium-uses-in-electronics.html |title=Terbium Uses in Electronics |last=Loewen |first=Eric |website=Stanford Advanced Materials |access-date=Aug 25, 2024}}</ref><ref>{{cite journal |last1=Sun |first1=L. |last2=Jiang |first2=S. |year=2010 |title=Compact all-fiber optical Faraday components using 65-wt%-terbium–doped fiber with a record Verdet constant of −32 rad/(Tm) |journal=Optics Express |volume=18 |issue=12 |pages=12191–12196 |doi=10.1364/OE.18.012191|pmid=20588343 |bibcode=2010OExpr..1812191S |doi-access=free }}</ref> Terbium-doped garnets are also used in optical isolators, which prevents reflected light from traveling back along the optical fiber.<ref>{{cite journal |last1=Geho |first1=Mikio |last2=Takagi |first2=Takashi |year=2005 |title=Development of Optical Isolators for Visible Light Using Terbium Aluminum Garnet (Tb<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>) Single Crystals |journal=Japanese Journal of Applied Physics |volume=44 |issue=7R |page=4967 |doi=10.1143/JJAP.44.4967|bibcode=2005JaJAP..44.4967G }}</ref>

Terbium oxides are used in green [[phosphor]]s in fluorescent lamps, color TV tubes,<ref name="CRC" /> and flat screen monitors.{{Sfn|Voncken|2016|p=100}} Terbium, along with all other [[Lanthanide|lanthanides]] except [[lanthanum]] and [[lutetium]], is [[Luminescence|luminescent]] in the 3+ oxidation state.<ref>{{Cite book |last1=Hänninen |first1=Pekka |url=https://books.google.com/books?id=SWxwcXO94M8C |title=Lanthanide Luminescence: Photophysical, Analytical and Biological Aspects |last2=Härmä |first2=Harri |date=2011-06-21 |publisher=Springer Science & Business Media |isbn=978-3-642-21023-5 |pages=15–20 |language=en}}</ref> The brilliant fluorescence allows terbium to be used as a [[Chemical probe|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 [[trichromatic]] lighting, 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.<ref name="CRC" />

In 2023, terbium compounds were used to create a lattice with a single [[iron]] atom that was then examined by [[synchrotron]] [[x-ray]] beam. This was the first successful attempt to characterize a single atom at sub-atomic levels.<ref name="2023-05-31_Nature">{{Cite journal |last1=Ajayi |first1=Tolulope M. |last2=Shirato |first2=Nozomi |last3=Rojas |first3=Tomas |last4=Wieghold |first4=Sarah |last5=Cheng |first5=Xinyue |last6=Latt |first6=Kyaw Zin |last7=Trainer |first7=Daniel J. |last8=Dandu |first8=Naveen K. |last9=Li |first9=Yiming |last10=Premarathna |first10=Sineth |last11=Sarkar |first11=Sanjoy |last12=Rosenmann |first12=Daniel |last13=Liu |first13=Yuzi |last14=Kyritsakas |first14=Nathalie |last15=Wang |first15=Shaoze |date=June 2023 |title=Characterization of just one atom using synchrotron X-rays |url=https://www.nature.com/articles/s41586-023-06011-w |journal=Nature |language=en |volume=618 |issue=7963 |pages=69–73 |doi=10.1038/s41586-023-06011-w |pmid=37259001 |bibcode=2023Natur.618...69A |osti=2001465 |s2cid=258992110 |issn=1476-4687}}</ref>

== Safety ==
Terbium, along with many of the other rare earth elements, is poorly studied in terms of its [[toxicology]] and [[Environmental impacts of rare-earth mining|environmental impacts]]. Few health-based guidance values for safe exposure to terbium are available.<ref>{{Cite journal |last1=Kowalczyk |first1=Ewelina |last2=Givelet |first2=Lucas |last3=Amlund |first3=Heidi |last4=Sloth |first4=Jens Jørgen |last5=Hansen |first5=Max |date=May 2022 |title=Risk assessment of rare earth elements, antimony, barium, boron, lithium, tellurium, thallium and vanadium in teas |journal=EFSA Journal |volume=20 |issue=Suppl 1 |pages=e200410 |doi=10.2903/j.efsa.2022.e200410 |pmc=9131585 |pmid=35634564}}</ref> No values are established in the United States by the [[Occupational Safety and Health Administration]] or [[American Conference of Governmental Industrial Hygienists]] at which terbium exposure becomes hazardous, and it is not considered a hazardous substance under the [[Globally Harmonized System of Classification and Labelling of Chemicals]].<ref>{{Cite web |date=January 26, 2016 |title=Terbium Safety Data Sheet |url=https://www.ameslab.gov/sites/default/files/inline-files/65_Terbium_SDS.pdf |access-date=August 25, 2024 |website=Ames Laboratory, [[U. S. Department of Energy]]}}</ref> 

Reviews of the toxicity of the rare earth elements place terbium and its compounds as "of low to moderately toxicity", remarking on the lack of detailed studies on their hazards<ref>{{Cite journal |last1=Rim |first1=Kyung Taek |last2=Koo |first2=Kwon Ho |last3=Park |first3=Jung Sun |date=March 2013 |title=Toxicological Evaluations of Rare Earths and Their Health Impacts to Workers: A Literature Review |journal=Safety and Health at Work |language=en |volume=4 |issue=1 |pages=12–26 |doi=10.5491/SHAW.2013.4.1.12 |pmc=3601293 |pmid=23516020}}</ref> and the lack of market demand forestalling evidence of toxicity.<ref>{{Cite journal |last1=Chen |first1=Haibin |last2=Chen |first2=Zhibiao |last3=Chen |first3=Zhiqiang |last4=Ou |first4=Xiaolin |last5=Chen |first5=Junjia |date=May 2020 |title=Calculation of Toxicity Coefficient of Potential Ecological Risk Assessment of Rare Earth Elements |url=https://link.springer.com/10.1007/s00128-020-02840-x |journal=Bulletin of Environmental Contamination and Toxicology |language=en |volume=104 |issue=5 |pages=582–587 |doi=10.1007/s00128-020-02840-x |pmid=32296855 |bibcode=2020BuECT.104..582C |issn=0007-4861|url-access=subscription }}</ref>

Some studies demonstrate environmental accumulation of terbium as hazardous to fish and plants.<ref>{{Cite journal |last1=Hanana |first1=Houda |last2=Taranu |first2=Zofia E. |last3=Turcotte |first3=Patrice |last4=Gagnon |first4=Christian |last5=Kowalczyk |first5=Joanna |last6=Gagné |first6=François |date=2021-07-10 |title=Sublethal effects of terbium and praseodymium in juvenile rainbow trout |url=https://linkinghub.elsevier.com/retrieve/pii/S0048969721011098 |journal=Science of the Total Environment |volume=777 |pages=146042 |doi=10.1016/j.scitotenv.2021.146042 |bibcode=2021ScTEn.77746042H |issn=0048-9697|url-access=subscription }}</ref><ref>{{Cite journal |last1=Sturla Lompré |first1=Julieta |last2=Moleiro |first2=Pedro |last3=De Marchi |first3=Lucia |last4=Soares |first4=Amadeu M. V. M. |last5=Pretti |first5=Carlo |last6=Chielini |first6=Federica |last7=Pereira |first7=Eduarda |last8=Freitas |first8=Rosa |date=2021-08-25 |title=Bioaccumulation and ecotoxicological responses of clams exposed to terbium and carbon nanotubes: Comparison between native (Ruditapes decussatus) and invasive (Ruditapes philippinarum) species |url=https://linkinghub.elsevier.com/retrieve/pii/S0048969721019847 |journal=Science of the Total Environment |volume=784 |pages=146914 |doi=10.1016/j.scitotenv.2021.146914 |pmid=33901954 |bibcode=2021ScTEn.78446914S |issn=0048-9697|url-access=subscription }}</ref> High exposures of terbium may enhance the toxicity of other substances causing [[endocytosis]] in [[Plant cell|plant cells]].<ref>{{Cite journal |last1=Cheng |first1=Mengzhu |last2=Zhou |first2=Qing |last3=Wang |first3=Lihong |last4=Jiao |first4=Yunlong |last5=Liu |first5=Yongqiang |last6=Tan |first6=Li |last7=Zhu |first7=Hong |last8=Nagawa |first8=Shingo |last9=Wei |first9=Haiyan |last10=Yang |first10=Zhenbiao |last11=Yang |first11=Qing |last12=Huang |first12=Xiaohua |date=2022-01-05 |title=A new mechanism by which environmental hazardous substances enhance their toxicities to plants |url=https://linkinghub.elsevier.com/retrieve/pii/S0304389421017696 |journal=Journal of Hazardous Materials |volume=421 |pages=126802 |doi=10.1016/j.jhazmat.2021.126802 |pmid=34396977 |bibcode=2022JHzM..42126802C |issn=0304-3894|url-access=subscription }}</ref>

== See also ==
* [[Terbium compounds]]
* [[List of elements facing shortage]]

== References ==
{{Reflist}}

=== Bibliography ===

* {{Cite book |last=Voncken |first=J.H.L. |title=The Rare Earth Elements: An Introduction |series=SpringerBriefs in Earth Sciences |publisher=Cham : Springer International Publishing |year=2016 |isbn=978-3-319-26809-5 |edition=1st |language=en |doi=10.1007/978-3-319-26809-5}}

== External links ==
{{Commons|Terbium}}
{{wiktionary|terbium}}
* [http://www.webelements.com/webelements/elements/text/Tb/index.html WebElements.com&nbsp;– Terbium]
* [http://education.jlab.org/itselemental/ele065.html It's Elemental&nbsp;– Terbium]
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{{Periodic table (navbox)}}
{{Terbium compounds}}

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[[Category:Terbium| ]]
[[Category:Chemical elements]]
[[Category:Chemical elements with hexagonal close-packed structure]]
[[Category:Ferromagnetic materials]]
[[Category:Lanthanides]]
[[Category:Reducing agents]]