Editing Terbium (section)

== 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}}</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>