View source for Isotopes of calcium

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{{more citations needed|date=May 2018}}
{{Infobox calcium isotopes}}

[[Calcium]] ({{sub|20}}Ca) has 26 known isotopes, ranging from {{sup|35}}Ca to {{sup|60}}Ca. There are five [[stable isotope]]s ({{sup|40}}Ca, {{sup|42}}Ca, {{sup|43}}Ca, {{sup|44}}Ca and {{sup|46}}Ca), plus one isotope ([[Calcium-48|{{sup|48}}Ca]]) with such a long [[half-life]] that it is for all practical purposes stable. The most abundant isotope, {{sup|40}}Ca, as well as the rare {{sup|46}}Ca, are theoretically unstable on energetic grounds, but their decay has not been observed. Calcium also has a [[cosmogenic isotope]], {{sup|41}}Ca, with [[half-life]] 99,400 years. Unlike [[cosmogenic isotope]]s that are produced in the [[Earth's atmosphere|air]], {{sup|41}}Ca is produced by [[neutron activation]] of {{sup|40}}Ca. Most of its production is in the upper metre of the soil column, where the cosmogenic neutron flux is still strong enough. {{sup|41}}Ca has received much attention in stellar studies because it decays to {{sup|41}}K, a critical indicator of solar system anomalies. The most stable artificial isotopes are {{sup|45}}Ca with half-life 163 days and {{sup|47}}Ca with half-life 4.5 days. All other calcium isotopes have half-lives of minutes or less.<ref name="nubase">{{Nubase 2016}}</ref>

Stable {{sup|40}}Ca comprises about 97% of natural calcium and is mainly created by nucleosynthesis in large stars. Similarly to {{sup|40}}Ar, however, some atoms of {{sup|40}}Ca are radiogenic, created through the radioactive decay of {{sup|40}}K. While [[K–Ar dating]] has been used extensively in the [[geology|geological]] sciences, the prevalence of {{sup|40}}Ca in nature initially impeded the proliferation of K-Ca dating in early studies, with only a handful of studies in the 20th century. Modern techniques using increasingly precise Thermal-Ionization ([[Thermal ionization mass spectrometry|TIMS]]) and Collision-Cell Multi-Collector Inductively-coupled plasma [[mass spectrometry]] ([[Inductively coupled plasma mass spectrometry|CC-MC-ICP-MS]]) techniques, however, have been used for successful [[K–Ca dating|K–Ca age dating]],<ref>{{Cite journal |last1=Marshall |first1=B. D. |last2=DePaolo |first2=D. J. |date=1982-12-01 |title=Precise age determinations and petrogenetic studies using the KCa method |url=https://www.sciencedirect.com/science/article/abs/pii/0016703782903763 |journal=Geochimica et Cosmochimica Acta |volume=46 |issue=12 |pages=2537–2545 |doi=10.1016/0016-7037(82)90376-3 |issn=0016-7037|url-access=subscription }}</ref><ref>{{Cite web |last=admin |title=K-Ca dating and Ca isotope composition of the oldest Solar System lava, Erg Chech 002 {{!}} Geochemical Perspectives Letters |url=https://www.geochemicalperspectivesletters.org/article2302/ |access-date=2024-10-16 |language=en-US}}</ref> as well as determining K losses from the lower continental crust<ref>{{Cite web |last=admin |title=Radiogenic Ca isotopes confirm post-formation K depletion of lower crust {{!}} Geochemical Perspectives Letters |url=https://www.geochemicalperspectivesletters.org/article1904/ |access-date=2024-10-16 |language=en-US}}</ref> and for source-tracing calcium contributions from various geologic reservoirs<ref>{{Cite journal |last1=Antonelli |first1=Michael A. |last2=DePaolo |first2=Donald J. |last3=Christensen |first3=John N. |last4=Wotzlaw |first4=Jörn-Frederik |last5=Pester |first5=Nicholas J. |last6=Bachmann |first6=Olivier |date=2021-09-16 |title=Radiogenic 40 Ca in Seawater: Implications for Modern and Ancient Ca Cycles |url=https://pubs.acs.org/doi/10.1021/acsearthspacechem.1c00179 |journal=ACS Earth and Space Chemistry |language=en |volume=5 |issue=9 |pages=2481–2492 |doi=10.1021/acsearthspacechem.1c00179 |issn=2472-3452|url-access=subscription }}</ref><ref>{{Cite journal |last1=Davenport |first1=Jesse |last2=Caro |first2=Guillaume |last3=France-Lanord |first3=Christian |date=2022-12-01 |title=Decoupling of physical and chemical erosion in the Himalayas revealed by radiogenic Ca isotopes |url=https://www.sciencedirect.com/science/article/abs/pii/S0016703722005804 |journal=Geochimica et Cosmochimica Acta |volume=338 |pages=199–219 |doi=10.1016/j.gca.2022.10.031 |issn=0016-7037|doi-access=free }}</ref> similar to [[Rb-Sr dating|Rb-Sr]].

Stable isotope variations of calcium (most typically {{sup|44}}Ca/{{sup|40}}Ca or <sup>44</sup>Ca/<sup>42</sup>Ca, denoted as 'δ{{sup|44}}Ca' and  'δ{{sup|44/42}}Ca' in delta notation) are also widely used across the natural sciences for a number of applications, ranging from early determination of [[osteoporosis]]<ref>{{Cite journal |last1=Eisenhauer |first1=A. |last2=Müller |first2=M. |last3=Heuser |first3=A. |last4=Kolevica |first4=A. |last5=Glüer |first5=C. -C. |last6=Both |first6=M. |last7=Laue |first7=C. |last8=Hehn |first8=U. v. |last9=Kloth |first9=S. |last10=Shroff |first10=R. |last11=Schrezenmeir |first11=J. |date=2019-06-01 |title=Calcium isotope ratios in blood and urine: A new biomarker for the diagnosis of osteoporosis |journal=Bone Reports |volume=10 |pages=100200 |doi=10.1016/j.bonr.2019.100200 |pmid=30997369 |pmc=6453776 |issn=2352-1872}}</ref> to quantifying [[Types of volcanic eruptions|volcanic eruption]] timescales.<ref>{{Cite journal |last1=Antonelli |first1=Michael A. |last2=Mittal |first2=Tushar |last3=McCarthy |first3=Anders |last4=Tripoli |first4=Barbara |last5=Watkins |first5=James M. |last6=DePaolo |first6=Donald J. |date=2019-10-08 |title=Ca isotopes record rapid crystal growth in volcanic and subvolcanic systems |journal=Proceedings of the National Academy of Sciences |language=en |volume=116 |issue=41 |pages=20315–20321 |doi=10.1073/pnas.1908921116 |doi-access=free |issn=0027-8424 |pmc=6789932 |pmid=31548431}}</ref> Other applications include: quantifying [[carbon sequestration]] efficiency in CO<sub>2</sub> injection sites<ref>{{Cite journal |last1=Pogge von Strandmann |first1=Philip A. E. |last2=Burton |first2=Kevin W. |last3=Snæbjörnsdóttir |first3=Sandra O. |last4=Sigfússon |first4=Bergur |last5=Aradóttir |first5=Edda S. |last6=Gunnarsson |first6=Ingvi |last7=Alfredsson |first7=Helgi A. |last8=Mesfin |first8=Kiflom G. |last9=Oelkers |first9=Eric H. |last10=Gislason |first10=Sigurður R. |date=2019-04-30 |title=Rapid CO2 mineralisation into calcite at the CarbFix storage site quantified using calcium isotopes |journal=Nature Communications |language=en |volume=10 |issue=1 |pages=1983 |doi=10.1038/s41467-019-10003-8 |pmid=31040283 |pmc=6491611 |issn=2041-1723}}</ref> and understanding [[ocean acidification]],<ref>{{Cite journal |last1=Fantle |first1=Matthew S. |last2=Ridgwell |first2=Andy |date=2020-08-05 |title=Towards an understanding of the Ca isotopic signal related to ocean acidification and alkalinity overshoots in the rock record |url=https://www.sciencedirect.com/science/article/abs/pii/S0009254120302114 |journal=Chemical Geology |volume=547 |pages=119672 |doi=10.1016/j.chemgeo.2020.119672 |issn=0009-2541|doi-access=free }}</ref> exploring both ubiquitous and rare magmatic processes, such as formation of [[Granite|granites]]<ref>{{Cite journal |last1=Antonelli |first1=Michael A. |last2=Yakymchuk |first2=Chris |last3=Schauble |first3=Edwin A. |last4=Foden |first4=John |last5=Janoušek |first5=Vojtěch |last6=Moyen |first6=Jean-François |last7=Hoffmann |first7=Jan |last8=Moynier |first8=Frédéric |last9=Bachmann |first9=Olivier |date=2023-04-15 |title=Granite petrogenesis and the δ44Ca of continental crust |url=https://www.sciencedirect.com/science/article/pii/S0012821X23000936 |journal=Earth and Planetary Science Letters |volume=608 |pages=118080 |doi=10.1016/j.epsl.2023.118080 |issn=0012-821X|hdl=20.500.11850/603069 |hdl-access=free }}</ref> and [[Carbonatite|carbonatites]],<ref>{{Cite web |last=admin |title=Calcium isotope fractionation during melt immiscibility and carbonatite petrogenesis {{!}} Geochemical Perspectives Letters |url=https://www.geochemicalperspectivesletters.org/article2338/ |access-date=2024-10-16 |language=en-US}}</ref> tracing modern and ancient [[Trophic web|trophic webs]] including in dinosaurs,<ref>{{Cite journal |last1=Skulan |first1=Joseph |last2=DePaolo |first2=Donald J. |last3=Owens |first3=Thomas L. |date=1997-06-01 |title=Biological control of calcium isotopic abundances in the global calcium cycle |url=https://www.sciencedirect.com/science/article/abs/pii/S0016703797000471 |journal=Geochimica et Cosmochimica Acta |volume=61 |issue=12 |pages=2505–2510 |doi=10.1016/S0016-7037(97)00047-1 |issn=0016-7037|url-access=subscription }}</ref><ref>{{Cite web |last=admin |title=Calcium stable isotopes place Devonian conodonts as first level consumers {{!}} Geochemical Perspectives Letters |url=https://www.geochemicalperspectivesletters.org/article1912/ |access-date=2024-10-16 |language=en-US}}</ref><ref>{{Cite journal |last1=Hassler |first1=A. |last2=Martin |first2=J. E. |last3=Amiot |first3=R. |last4=Tacail |first4=T. |last5=Godet |first5=F. Arnaud |last6=Allain |first6=R. |last7=Balter |first7=V. |date=2018-04-11 |title=Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs |journal=Proceedings of the Royal Society B: Biological Sciences |language=en |volume=285 |issue=1876 |pages=20180197 |doi=10.1098/rspb.2018.0197 |issn=0962-8452 |pmc=5904318 |pmid=29643213}}</ref> assessing [[weaning]] practices in ancient humans,<ref>{{Cite journal |last1=Tacail |first1=Théo |last2=Thivichon-Prince |first2=Béatrice |last3=Martin |first3=Jeremy E. |last4=Charles |first4=Cyril |last5=Viriot |first5=Laurent |last6=Balter |first6=Vincent |date=2017-06-13 |title=Assessing human weaning practices with calcium isotopes in tooth enamel |journal=Proceedings of the National Academy of Sciences |language=en |volume=114 |issue=24 |pages=6268–6273 |doi=10.1073/pnas.1704412114 |doi-access=free |issn=0027-8424 |pmc=5474782 |pmid=28559355}}</ref> and a plethora of other emerging applications.

== List of isotopes ==
{{Anchor|Calcium-33|Calcium-34|Calcium-61}}

<!--Please delete anchor(s) from the list above or table below if adding a dedicated isotope section(s).-->

{{Isotopes table
|symbol=Ca
|refs=NUBASE2020, AME2020 II
|notes=mass#, unc(), var[], spin(), spin#, hl-nst, daughter-st, EC, n, p
}}
|-id=Calcium-35
| rowspan=3|{{sup|35}}Ca
| rowspan=3 style="text-align:right" | 20
| rowspan=3 style="text-align:right" | 15
| rowspan=3|35.00557(22)#
| rowspan=3|25.7(2)&nbsp;ms
| [[Beta decay|β{{sup|+}}]], [[proton emission|p]] (95.8%)
| {{sup|34}}Ar
| rowspan=3|1/2+#
| rowspan=3|
| rowspan=3|
|-
| β{{sup|+}}, 2p (4.2%)
| {{sup|33}}Cl
|-
| β{{sup|+}} (rare)
| {{sup|35}}K
|-id=Calcium-36
| rowspan=2|{{sup|36}}Ca
| rowspan=2 style="text-align:right" | 20
| rowspan=2 style="text-align:right" | 16
| rowspan=2|35.993074(43)
| rowspan=2|100.9(13)&nbsp;ms
| β{{sup|+}}, p (51.2%)
| {{sup|35}}Ar
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| β{{sup|+}} (48.8%)
| {{sup|36}}K
|-id=Calcium-37
| rowspan=2|{{sup|37}}Ca
| rowspan=2 style="text-align:right" | 20
| rowspan=2 style="text-align:right" | 17
| rowspan=2|36.98589785(68)
| rowspan=2|181.0(9)&nbsp;ms
| β{{sup|+}}, p (76.8%)
| '''{{sup|36}}Ar'''
| rowspan=2|3/2+
| rowspan=2|
| rowspan=2|
|-
| β{{sup|+}} (23.2%)
| {{sup|37}}K
|-id=Calcium-38
| {{sup|38}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 18
| 37.97631922(21)
| 443.70(25)&nbsp;ms
| β{{sup|+}}
| {{sup|38}}K
| 0+
|
|
|-id=Calcium-39
| {{sup|39}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 19
| 38.97071081(64)
| 860.3(8)&nbsp;ms
| β{{sup|+}}
| '''{{sup|39}}K'''
| 3/2+
|
|
|-id=Calcium-40
| {{sup|40}}Ca<ref group="n">Heaviest observationally stable nuclide with equal numbers of protons and neutrons</ref>
| style="text-align:right" | 20
| style="text-align:right" | 20
| 39.962590850(22)
| colspan=3 align=center|'''[[Observationally stable]]'''<ref group="n">Believed to undergo [[double electron capture]] to '''{{sup|40}}Ar''' with a half-life no less than 9.9×10{{sup|21}} y</ref>
| 0+
| 0.9694(16)
| 0.96933–0.96947
|-id=Calcium-41
| {{sup|41}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 21
| 40.96227791(15)
| 9.94(15)×10{{sup|4}} y
| [[electron capture|EC]]
| '''{{sup|41}}K'''
| 7/2−
| Trace<ref group="n">[[Cosmogenic nuclide]]</ref>
|
|-id=Calcium-42
| {{sup|42}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 22
| 41.95861778(16)
| colspan=3 align=center|'''Stable'''
| 0+
| 0.00647(23)
| 0.00646–0.00648
|-id=Calcium-43
| {{sup|43}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 23
| 42.95876638(24)
| colspan=3 align=center|'''Stable'''
| 7/2−
| 0.00135(10)
| 0.00135–0.00135
|-id=Calcium-44
| {{sup|44}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 24
| 43.95548149(35)
| colspan=3 align=center|'''Stable'''
| 0+
| 0.0209(11)
| 0.02082–0.02092
|-id=Calcium-45
| {{sup|45}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 25
| 44.95618627(39)
| 162.61(9)&nbsp;d
| β{{sup|−}}
| '''{{sup|45}}Sc'''
| 7/2−
|
|
|-id=Calcium-46
| {{sup|46}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 26
| 45.9536877(24)
| colspan=3 align=center|'''Observationally stable'''<ref group="n">Believed to undergo β{{sup|−}}β{{sup|−}} decay to '''{{sup|46}}Ti'''</ref>
| 0+
| 4×10{{sup|−5}}
| 4×10{{sup|−5}}–4×10{{sup|−5}}
|-id=Calcium-47
| {{sup|47}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 27
| 46.9545411(24)
| 4.536(3)&nbsp;d
| β{{sup|−}}
| {{sup|47}}Sc
| 7/2−
|
|
|-
| [[Calcium-48|{{sup|48}}Ca]]<ref group="n" name="PN">[[Primordial nuclide|Primordial]] [[radionuclide]]</ref><ref group="n">Believed to be capable of undergoing [[Double beta decay|triple beta decay]] with very long partial half-life</ref>
| style="text-align:right" | 20
| style="text-align:right" | 28
| 47.952522654(18)
| '''5.6(10)×10{{sup|19}}&nbsp;y'''|| β{{sup|−}}β{{sup|−}}<ref group="n">Lightest nuclide known to undergo [[double beta decay]]</ref>{{refn|group="n"|Theorized to also undergo β{{sup|−}} decay to {{sup|48}}Sc with a [[partial half-life]] exceeding 1.1{{su|p=+0.8|b=−0.6}}×10{{sup|21}} years<ref name="48Ca-Aunola">{{cite journal |last1=Aunola |first1=M. |last2=Suhonen |first2=J. |last3=Siiskonen |first3=T. |title=Shell-model study of the highly forbidden beta decay {{sup|48}}Ca → {{sup|48}}Sc |date=1999 |journal=[[EPL (journal)|EPL]] |volume=46 |issue=5 |page=577 |doi=10.1209/epl/i1999-00301-2|bibcode=1999EL.....46..577A |s2cid=250836275 }}</ref>}}
| '''{{sup|48}}Ti'''
| 0+
| 0.00187(21)
| 0.00186–0.00188
|-id=Calcium-49
| {{sup|49}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 29
| 48.95566263(19)
| 8.718(6)&nbsp;min
| β{{sup|−}}
| {{sup|49}}Sc
| 3/2−
|
|
|-id=Calcium-50
| {{sup|50}}Ca
| style="text-align:right" | 20
| style="text-align:right" | 30
| 49.9574992(17)
| 13.45(5)&nbsp;s
| β{{sup|−}}
| {{sup|50}}Sc
| 0+
| 
| 
|-id=Calcium-51
| rowspan=2|{{sup|51}}Ca
| rowspan=2 style="text-align:right" | 20
| rowspan=2 style="text-align:right" | 31
| rowspan=2|50.96099566(56)
| rowspan=2|10.0(8)&nbsp;s
| β{{sup|−}}
| {{sup|51}}Sc
| rowspan=2|3/2−
| rowspan=2|
| rowspan=2|
|-
| β{{sup|−}}, [[neutron emission|n]]?
| {{sup|50}}Sc
|-id=Calcium-52
| rowspan=2|{{sup|52}}Ca
| rowspan=2 style="text-align:right" | 20
| rowspan=2 style="text-align:right" | 32
| rowspan=2|51.96321365(72)
| rowspan=2|4.6(3)&nbsp;s
| β{{sup|−}} (>98%)
| {{sup|52}}Sc
| rowspan=2|0+
| rowspan=2|
| rowspan=2|
|-
| β{{sup|−}}, n (<2%)
| {{sup|51}}Sc
|-id=Calcium-53
| rowspan=2|{{sup|53}}Ca
| rowspan=2 style="text-align:right" | 20
| rowspan=2 style="text-align:right" | 33
| rowspan=2|52.968451(47)
| rowspan=2|461(90)&nbsp;ms
| β{{sup|−}} (60%)
| {{sup|53}}Sc
| rowspan=2|1/2−#
| rowspan=2|
| rowspan=2|
|-
| β{{sup|−}}, n (40%)
| {{sup|52}}Sc
|-id=Calcium-54
| rowspan=3|{{sup|54}}Ca
| rowspan=3 style="text-align:right" | 20
| rowspan=3 style="text-align:right" | 34
| rowspan=3|53.972989(52)
| rowspan=3|90(6)&nbsp;ms
| β{{sup|−}}
| {{sup|54}}Sc
| rowspan=3|0+
| rowspan=3|
| rowspan=3|
|-
| β{{sup|−}}, n?
| {{sup|53}}Sc
|-
| β{{sup|−}}, 2n?
| {{sup|52}}Sc
|-id=Calcium-55
| rowspan=3|{{sup|55}}Ca
| rowspan=3 style="text-align:right" | 20
| rowspan=3 style="text-align:right" | 35
| rowspan=3|54.97998(17)
| rowspan=3|22(2)&nbsp;ms
| β{{sup|−}}
| {{sup|55}}Sc
| rowspan=3|5/2−#
| rowspan=3|
| rowspan=3|
|-
| β{{sup|−}}, n?
| {{sup|54}}Sc
|-
| β{{sup|−}}, 2n?
| {{sup|53}}Sc
|-id=Calcium-56
| rowspan=3|{{sup|56}}Ca
| rowspan=3 style="text-align:right" | 20
| rowspan=3 style="text-align:right" | 36
| rowspan=3|55.98550(27)
| rowspan=3|11(2)&nbsp;ms
| β{{sup|−}}
| {{sup|56}}Sc
| rowspan=3|0+
| rowspan=3|
| rowspan=3|
|-
| β{{sup|−}}, n?
| {{sup|55}}Sc
|-
| β{{sup|−}}, 2n?
| {{sup|54}}Sc
|-id=Calcium-57
| rowspan=3|{{sup|57}}Ca
| rowspan=3 style="text-align:right" | 20
| rowspan=3 style="text-align:right" | 37
| rowspan=3|56.99296(43)#
| rowspan=3|8#&nbsp;ms [>620&nbsp;ns]
| β{{sup|−}}?
| {{sup|57}}Sc
| rowspan=3|5/2−#
| rowspan=3|
| rowspan=3|
|-
| β{{sup|−}}, n?
| {{sup|56}}Sc
|-
| β{{sup|−}}, 2n?
| {{sup|55}}Sc
|-id=Calcium-58
| rowspan=3|{{sup|58}}Ca
| rowspan=3 style="text-align:right" | 20
| rowspan=3 style="text-align:right" | 38
| rowspan=3|57.99836(54)#
| rowspan=3|4#&nbsp;ms [>620&nbsp;ns]
| β{{sup|−}}?
| {{sup|58}}Sc
| rowspan=3|0+
| rowspan=3|
| rowspan=3|
|-
| β{{sup|−}}, n?
| {{sup|57}}Sc
|-
| β{{sup|−}}, 2n?
| {{sup|56}}Sc
|-id=Calcium-59
| rowspan=3|{{sup|59}}Ca
| rowspan=3 style="text-align:right" | 20
| rowspan=3 style="text-align:right" | 39
| rowspan=3|59.00624(64)#
| rowspan=3|5#&nbsp;ms [>400&nbsp;ns]
| β{{sup|−}}?
| {{sup|59}}Sc
| rowspan=3|5/2−#
| rowspan=3|
| rowspan=3|
|-
| β{{sup|−}}, n?
| {{sup|58}}Sc
|-
| β{{sup|−}}, 2n?
| {{sup|57}}Sc
|-
| rowspan=3|{{sup|60}}Ca
| rowspan=3 style="text-align:right" | 20
| rowspan=3 style="text-align:right" | 40
| rowspan=3|60.01181(75)#
| rowspan=3|2#&nbsp;ms [>400&nbsp;ns]
| β{{sup|−}}?
| {{sup|60}}Sc
| rowspan=3|0+
| rowspan=3|
| rowspan=3|
|-
| β{{sup|−}}, n?
| {{sup|59}}Sc
|-
| β{{sup|−}}, 2n?
| {{sup|58}}Sc
{{Isotopes table/footer}}

==Calcium-48==
{{main|Calcium-48}}

[[File:Calcium-48 carbonate.png|thumb|About 2 g of calcium-48]]

Calcium-48 is a doubly magic nucleus with 28 neutrons; unusually neutron-rich for a light primordial nucleus. It decays via [[double beta decay]] with an extremely long half-life of about 6.4×10{{sup|19}}&nbsp;years, though single beta decay is also theoretically possible.<ref name=Arnold2016>{{Cite journal
 |last1=Arnold |first1=R.
 |display-authors=etal
 |year=2016
 |collaboration=[[NEMO-3 Collaboration]]
 |title= Measurement of the double-beta decay half-life and search for the neutrinoless double-beta decay of {{sup|48}}Ca with the NEMO-3 detector
 |journal=[[Physical Review D]]
 |volume=93 |issue=11
 |pages=112008
 |doi= 10.1103/PhysRevD.93.112008
|arxiv=1604.01710|bibcode=2016PhRvD..93k2008A}}</ref> This decay can analyzed with the ''sd'' [[nuclear shell model]], and it is more energetic (4.27&nbsp;[[MeV]]) than any other double beta decay.<ref name="Balysh">{{cite journal | last = Balysh | first = A. | year = 1996 | title = Double Beta Decay of {{sup|48}}Ca | journal = Physical Review Letters | volume = 77 | pages = 5186–5189 | doi = 10.1103/PhysRevLett.77.5186 | pmid = 10062737 | issue = 26 | bibcode=1996PhRvL..77.5186B|arxiv = nucl-ex/9608001 |display-authors=etal}}</ref> It can also be used as a precursor for neutron-rich and superheavy nuclei.<ref>{{cite journal | last = Notani | first = M. | year = 2002 | title = New neutron-rich isotopes, {{sup|34}}Ne, {{sup|37}}Na and {{sup|43}}Si, produced by fragmentation of a 64A MeV {{sup|48}}Ca beam | journal = Physics Letters B | volume = 542 | issue = 1–2 | pages = 49–54 | doi = 10.1016/S0370-2693(02)02337-7 |bibcode = 2002PhLB..542...49N |display-authors=etal}}</ref><ref>{{cite journal | last = Oganessian | first = Yu. Ts. |date=October 2006 | title = Synthesis of the isotopes of elements 118 and 116 in the {{sup|249}}Cf and {{sup|245}}Cm + {{sup|48}}Ca fusion reactions | journal = Physical Review C | volume = 74 | pages = 044602 | doi = 10.1103/PhysRevC.74.044602 | bibcode=2006PhRvC..74d4602O | issue = 4|display-authors=etal| doi-access = free }}</ref>

==Calcium-60==
Calcium-60 is the heaviest known isotope {{as of|2020|lc=y}}.<ref name="NUBASE2020"/> First observed in 2018 at [[Riken]] alongside {{sup|59}}Ca and seven isotopes of other elements,<ref name="riken">{{cite journal |last1=Tarasov |first1=O. B. |last2=Ahn |first2=D. S. |last3=Bazin |first3=D. |last4=Fukuda |first4=N. |last5=Gade |first5=A. |last6=Hausmann |first6=M. |last7=Inabe |first7=N. |last8=Ishikawa |first8=S. |last9=Iwasa |first9=N. |last10=Kawata |first10=K. |last11=Komatsubara |first11=T. |last12=Kubo |first12=T. |last13=Kusaka |first13=K. |last14=Morrissey |first14=D. J. |last15=Ohtake |first15=M. |last16=Otsu |first16=H. |last17=Portillo |first17=M. |last18=Sakakibara |first18=T. |last19=Sakurai |first19=H. |last20=Sato |first20=H. |last21=Sherrill |first21=B. M. |last22=Shimizu |first22=Y. |last23=Stolz |first23=A. |last24=Sumikama |first24=T. |last25=Suzuki |first25=H. |last26=Takeda |first26=H. |last27=Thoennessen |first27=M. |last28=Ueno |first28=H. |last29=Yanagisawa |first29=Y. |last30=Yoshida |first30=K. |title=Discovery of {{sup|60}}Ca and Implications For the Stability of {{sup|70}}Ca |journal=Physical Review Letters |date=11 July 2018 |volume=121 |issue=2 |page=022501 |doi=10.1103/PhysRevLett.121.022501 |display-authors=3|doi-access=free |pmid=30085743 }}</ref> its existence suggests that there are additional even-''N'' isotopes of calcium up to at least {{sup|70}}Ca, while {{sup|59}}Ca is probably the last bound isotope with odd ''N''.<ref>{{cite journal |last1=Neufcourt |first1=Léo |last2=Cao |first2=Yuchen |last3=Nazarewicz |first3=Witold |last4=Olsen |first4=Erik |last5=Viens |first5=Frederi |title=Neutron Drip Line in the Ca Region from Bayesian Model Averaging |journal=Physical Review Letters |date=14 February 2019 |volume=122 |issue=6 |page=062502 |doi=10.1103/PhysRevLett.122.062502 |pmid=30822058 |arxiv=1901.07632 |display-authors=3}}</ref> Earlier predictions had estimated the neutron drip line to occur at {{sup|60}}Ca, with {{sup|59}}Ca unbound.<ref name="riken"/>

In the neutron-rich region, ''N'' = 40 becomes a [[magic number (physics)|magic number]], so {{sup|60}}Ca was considered early on to be a possibly doubly magic nucleus, as is observed for the {{sup|68}}Ni [[isotone]].<ref>{{cite journal |last1=Gade |first1=A. |last2=Janssens |first2=R. V. F. |last3=Weisshaar |first3=D. |last4=Brown |first4=B. A. |last5=Lunderberg |first5=E. |last6=Albers |first6=M. |last7=Bader |first7=V. M. |last8=Baugher |first8=T. |last9=Bazin |first9=D. |last10=Berryman |first10=J. S. |last11=Campbell |first11=C. M. |last12=Carpenter |first12=M. P. |last13=Chiara |first13=C. J. |last14=Crawford |first14=H. L. |last15=Cromaz |first15=M. |last16=Garg |first16=U. |last17=Hoffman |first17=C. R. |last18=Kondev |first18=F. G. |last19=Langer |first19=C. |last20=Lauritsen |first20=T. |last21=Lee |first21=I. Y. |last22=Lenzi |first22=S. M. |last23=Matta |first23=J. T. |last24=Nowacki |first24=F. |last25=Recchia |first25=F. |last26=Sieja |first26=K. |last27=Stroberg |first27=S. R. |last28=Tostevin |first28=J. A. |last29=Williams |first29=S. J. |last30=Wimmer |first30=K. |last31=Zhu |first31=S. |title=Nuclear Structure Towards ''N''&nbsp;=&nbsp;40 {{sup|60}}Ca: In-Beam γ -Ray Spectroscopy of {{sup|58,&nbsp;60}}Ti |journal=Physical Review Letters |date=21 March 2014 |volume=112 |issue=11 |page=112503 |doi=10.1103/PhysRevLett.112.112503 |pmid=24702356 |display-authors=3|arxiv=1402.5944 }}</ref><ref name="62Ti">{{cite journal |last1=Cortés |first1=M.L. |last2=Rodriguez |first2=W. |last3=Doornenbal |first3=P. |last4=Obertelli |first4=A. |last5=Holt |first5=J.D. |last6=Lenzi |first6=S.M. |last7=Menéndez |first7=J. |last8=Nowacki |first8=F. |last9=Ogata |first9=K. |last10=Poves |first10=A. |last11=Rodríguez |first11=T.R. |last12=Schwenk |first12=A. |last13=Simonis |first13=J. |last14=Stroberg |first14=S.R. |last15=Yoshida |first15=K. |last16=Achouri |first16=L. |last17=Baba |first17=H. |last18=Browne |first18=F. |last19=Calvet |first19=D. |last20=Château |first20=F. |last21=Chen |first21=S. |last22=Chiga |first22=N. 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|last59=Kondo |first59=Y. |last60=Koseoglou |first60=P. |last61=Lee |first61=J. |last62=Lehr |first62=C. |last63=Linh |first63=B.D. |last64=Lokotko |first64=T. |last65=MacCormick |first65=M. |last66=Moschner |first66=K. |last67=Nakamura |first67=T. |last68=Park |first68=S.Y. |last69=Rossi |first69=D. |last70=Sahin |first70=E. |last71=Sohler |first71=D. |last72=Söderström |first72=P.-A. |last73=Takeuchi |first73=S. |last74=Toernqvist |first74=H. |last75=Vaquero |first75=V. |last76=Wagner |first76=V. |last77=Wang |first77=S. |last78=Werner |first78=V. |last79=Xu |first79=X. |last80=Yamada |first80=H. |last81=Yan |first81=D. |last82=Yang |first82=Z. |last83=Yasuda |first83=M. |last84=Zanetti |first84=L. |title=Shell evolution of ''N''&nbsp;=&nbsp;40 isotones towards {{sup|60}}Ca: First spectroscopy of {{sup|62}}Ti |journal=Physics Letters B |date=January 2020 |volume=800 |pages=135071 |doi=10.1016/j.physletb.2019.135071 |display-authors=3|doi-access=free |arxiv=1912.07887 }}</ref> However, subsequent spectroscopic measurements of the nearby nuclides {{sup|56}}Ca, {{sup|58}}Ca, and {{sup|62}}Ti instead predict that it should lie on the [[island of inversion]] known to exist around {{sup|64}}Cr.<ref name="62Ti"/><ref name="56,58Ca">{{cite journal |last1=Chen |first1=S. |last2=Browne |first2=F. |last3=Doornenbal |first3=P. |last4=Lee |first4=J. |last5=Obertelli |first5=A. |last6=Tsunoda |first6=Y. |last7=Otsuka |first7=T. |last8=Chazono |first8=Y. |last9=Hagen |first9=G. |last10=Holt |first10=J.D. |last11=Jansen |first11=G.R. |last12=Ogata |first12=K. |last13=Shimizu |first13=N. |last14=Utsuno |first14=Y. |last15=Yoshida |first15=K. |last16=Achouri |first16=N.L. |last17=Baba |first17=H. |last18=Calvet |first18=D. |last19=Château |first19=F. |last20=Chiga |first20=N. |last21=Corsi |first21=A. |last22=Cortés |first22=M.L. |last23=Delbart |first23=A. |last24=Gheller |first24=J.-M. |last25=Giganon |first25=A. |last26=Gillibert |first26=A. |last27=Hilaire |first27=C. 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== See also ==
'''Daughter products other than calcium'''
* [[Isotopes of scandium]]
* [[Isotopes of potassium]]
* [[Isotopes of argon]]

== References ==
{{Reflist}}

==Further reading==
* C. Michael Hogan. 2010. [http://www.eoearth.org/article/Calcium?topic=49557 ''Calcium''. ed. A. Jorgenson and C. Cleveland. ''Encyclopedia of Earth'', National Council for Science and the Environment, Washington, D.C.]

== External links ==
*[https://ww.isotopes.gov National Isotope Development Center Official website]{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}
*[https://web.archive.org/web/20120506025523/http://ie.lbl.gov/education/parent/Ca_iso.htm Calcium isotopes data from ''The Berkeley Laboratory Isotopes Project's'']

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[[Category:Isotopes of calcium| ]]
[[Category:Calcium]]
[[Category:Lists of isotopes by element|Calcium]]