Editing Scandium (section)

==Properties==

===Chemical characteristics===
Scandium is a soft metal with a silvery appearance. It develops a slightly yellowish or pinkish cast when [[redox|oxidized]] by air. It is susceptible to weathering and dissolves slowly in most dilute [[acids]]. It does not react with a 1:1 mixture of [[nitric acid]] ({{chem2|HNO3}}) and 48.0% [[hydrofluoric acid]] ({{chem2|HF}}), possibly due to the formation of an impermeable [[passivation (chemistry)|passive layer]]. Scandium turnings ignite in the air with a brilliant yellow flame to form [[scandium oxide]].<ref>"[http://periodic.lanl.gov/21.shtml Scandium]." Los Alamos National Laboratory. Retrieved 2013-07-17.</ref>

===Isotopes===
{{Main|Isotopes of scandium}}
In nature, scandium is found exclusively as the [[isotope]] <sup>45</sup>Sc, which has a [[nuclear spin]] of {{frac|7|2}}; this is its only stable isotope.<ref name=Meierfrankenfeld2011>{{Cite journal |last1=Meierfrankenfeld |first1=D. |last2=Bury |first2=A. |last3=Thoennessen |first3=M. |date=2011 |title=Discovery of scandium, titanium, mercury, and einsteinium isotopes |url=https://linkinghub.elsevier.com/retrieve/pii/S0092640X10000914 |journal=Atomic Data and Nuclear Data Tables |language=en |volume=97 |issue=2 |pages=134–151 |doi=10.1016/j.adt.2010.11.001|arxiv=1003.5128 |bibcode=2011ADNDT..97..134M }}</ref> 

The known isotopes of scandium range from <sup>37</sup>Sc to <sup>62</sup>Sc.{{NUBASE2020|name}} The most stable radioisotope is <sup>46</sup>Sc, which has a [[half-life]] of 83.8&nbsp;days. Others are <sup>47</sup>Sc, 3.35&nbsp;days; the [[positron]] emitter [[scandium-44|<sup>44</sup>Sc]], 4&nbsp;hours; and <sup>48</sup>Sc, 43.7&nbsp;hours. All of the remaining [[radioactivity|radioactive]] isotopes have half-lives less than 4&nbsp;hours, and the majority of them have half-lives less than 2&nbsp;minutes. 
The low mass isotopes are very difficult to create.<ref name=Meierfrankenfeld2011/> The initial detection of <sup>37</sup>Sc and <sup>38</sup>Sc only resulted in the characterization of their mass excess.<ref name="37,38Sc">{{cite journal | last1=Dronchi | first1=N. | last2=Charity | first2=R. J. | last3=Sobotka | first3=L. G. | last4=Brown | first4=B. A. | last5=Weisshaar | first5=D. | last6=Gade | first6=A. | last7=Brown | first7=K. W. | last8=Reviol | first8=W. | last9=Bazin | first9=D. | last10=Farris | first10=P. J. | last11=Hill | first11=A. M. | last12=Li | first12=J. | last13=Longfellow | first13=B. | last14=Rhodes | first14=D. | last15=Paneru | first15=S. N. | last16=Gillespie | first16=S. A. | last17=Anthony | first17=A. K. | last18=Rubino | first18=E. | last19=Biswas | first19=S. | title=Evolution of shell gaps in the neutron-poor calcium region from invariant-mass spectroscopy of <sup>37,38</sup>Sc, <sup>35</sup>Ca, and <sup>34</sup>K | journal=Physical Review C | volume=110 | issue=3 | date=2024-09-12 | issn=2469-9985 | doi=10.1103/PhysRevC.110.L031302}}</ref><ref>[https://frib.msu.edu/public/nuclides/newly-discovered Latest discovered isotopes], Discovery of Nuclides Project</ref>
Scandium also has five [[nuclear isomer]]s: the most stable of these is <sup>44m2</sup>Sc (''t''<sub>1/2</sub> = 58.6&nbsp;h).<ref name="Audi">{{cite journal |title=The NUBASE Evaluation of Nuclear and Decay Properties |journal=[[Nuclear Physics A]] |volume=729 |issue=1 |pages=3–128 |date=2003 |doi=10.1016/j.nuclphysa.2003.11.001 |bibcode=2003NuPhA.729....3A |last1=Audi |first1=Georges |last2=Bersillon |first2=Olivier |last3=Blachot |first3=Jean |last4=Wapstra |first4=Aaldert Hendrik |url=http://hal.in2p3.fr/in2p3-00014184 |citeseerx= 10.1.1.692.8504 }}</ref>

The primary [[decay mode]] of ground-state scandium isotopes at masses lower than the only stable isotope, <sup>45</sup>Sc, is [[electron capture]] (or [[positron emission]]), but the lightest isotopes (<sup>37</sup>Sc to <sup>39</sup>Sc) undergo [[proton emission]] instead, all three of these producing [[calcium]] isotopes. The primary decay mode at masses above <sup>45</sup>Sc is [[beta emission]], producing [[titanium]] isotopes.{{NUBASE2020|name}}

===Occurrence===
In [[abundance of elements in Earth's crust|Earth's crust]], scandium is not rare. Estimates vary from 18 to 25&nbsp;ppm, which is comparable to the abundance of [[cobalt]] (20–30&nbsp;ppm). Scandium is only the 50th most common element on Earth (35th most abundant element in the crust), but it is the 23rd most common element in the [[Sun]]<ref name="rubber">{{cite book|title= CRC Handbook of Chemistry and Physics|first= David R.|last= Lide|date= 2004|isbn= 978-0-8493-0485-9|pages= [https://archive.org/details/crchandbookofche81lide/page/4 4–28]|publisher= CRC Press|location= Boca Raton|url-access= registration|url= https://archive.org/details/crchandbookofche81lide/page/4}}</ref> and the 26th most abundant element in the stars.<ref>{{Cite web |title=Chemistry for Kids: Elements - Scandium |url=https://www.ducksters.com/science/chemistry/scandium.php |access-date=2024-06-12 |website=www.ducksters.com}}</ref> However, scandium is distributed sparsely and occurs in trace amounts in many [[mineral]]s.<ref>{{cite book |first= F.|last= Bernhard|chapter= Scandium mineralization associated with hydrothermal lazurite-quartz veins in the Lower Austroalpie Grobgneis complex, East Alps, Austria|title= Mineral Deposits in the Beginning of the 21st Century|date= 2001|isbn= 978-90-265-1846-1 |publisher= Balkema |location= Lisse}}</ref> Rare minerals from Scandinavia<ref name="Thort">{{cite journal|title= Scandium – Mineraler I Norge|first= Roy|last= Kristiansen|journal= Stein|date= 2003|pages= 14–23|language= no|url= http://www.nags.net/Stein/2003/Sc-mineraler.pdf}}</ref> and [[Madagascar]]<ref name="Mada">{{cite journal|journal=Geological Journal|volume= 22|page= 253|date= 1987|title= Mineralized pegmatites in Africa|first= O.|last= von Knorring|author2=Condliffe, E. |issue= S2|doi= 10.1002/gj.3350220619|bibcode= 1987GeolJ..22S.253V}}</ref> such as [[thortveitite]], [[euxenite]], and [[gadolinite]] are the only known concentrated sources of this element. Thortveitite can contain up to 45% of scandium in the form of [[scandium oxide]].<ref name="Thort" />

The stable form of scandium is created in [[supernova]]s via the [[r-process]].<ref>{{cite journal|author= Cameron, A.G.W.|title=Stellar Evolution, Nuclear Astrophysics, and Nucleogenesis |journal=CRL-41|date=June 1957|url=http://www.fas.org/sgp/eprint/CRL-41.pdf}}</ref> Also, scandium is created by [[cosmic ray spallation]] of the more abundant [[iron]] nuclei.
*<sup>28</sup>Si + 17n → <sup>45</sup>Sc (r-process)
*<sup>56</sup>Fe + p → <sup>45</sup>Sc + <sup>11</sup>C + n (cosmic ray spallation)