Editing Terbium (section)

=== 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}}</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.