# Isotopes of nitrogen
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{{Short description|none}}
{{Infobox nitrogen isotopes}}
Natural [nitrogen](/source/nitrogen) (7N) consists of two stable [isotope](/source/isotope)s: the vast majority (99.62%) of naturally occurring nitrogen is nitrogen-14, with the remainder (0.38%) being nitrogen-15. Thirteen [radioisotope](/source/radioisotope)s are also known, with [atomic mass](/source/atomic_mass)es ranging from 9 to 23, along with three [nuclear isomer](/source/nuclear_isomer)s. All of these radioisotopes are short-lived, the longest-lived being 13N with a half-life of 9.965 minutes. All of the others have half-lives shorter than ten seconds. Isotopes lighter than the stable ones generally decay to [isotopes of carbon](/source/isotopes_of_carbon), and those heavier [beta decay](/source/beta_decay) to [isotopes of oxygen](/source/isotopes_of_oxygen).
Nitrogen-13 is a positron emitter and one of the main isotopes used in medical [PET scan](/source/PET_scan)s.
==List of isotopes==
{{Anchor|Nitrogen-24}}
{{Isotopes table
| symbol = N
| refs = NUBASE2020, AME2020 II, IsotopeFRIB, IsomerFRIB
| notes = m, resonance, unc(), mass#, spin(), spin#, daughter-st, p, n, IT, discoveryname
}}
|-id=Nitrogen-9
| {{SimpleNuclide|Nitrogen|9}}[{{cite news |url=https://www.science.org/content/article/fleeting-form-nitrogen-stretches-nuclear-theory-its-limits |title=Fleeting form of nitrogen stretches nuclear theory to its limits |last=Cho |first=Adrian |website=[science.org](/source/science.org) |date=25 September 2023 |access-date=27 September 2023}}]
| style="text-align:right" | 7
| style="text-align:right" | 2
|
| style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/7/9.pdf 2023]
| <1 as
[{{val|780.0|(9.3)|u=keV}}]
| p
| {{SimpleNuclide|Carbon|10}}
| 1/2+
|
|
|-id=Nitrogen-12
| rowspan=2|{{SimpleNuclide|Nitrogen|12}}
| rowspan=2 style="text-align:right" | 7
| rowspan=2 style="text-align:right" | 5
| rowspan=2|{{val|12.0186132|(11)}}
| rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/7/12.pdf 1949]
| rowspan=2|{{val|11.000|(16)|u=ms}}
| [β+](/source/beta_decay) ({{val|98.07|(4)|u=%}})
| '''{{SimpleNuclide|Carbon|12}}'''
| rowspan=2|1+
| rowspan=2|
| rowspan=2|
|-
| β+α ({{val|1.93|(4)|u=%}})
| {{SimpleNuclide|Beryllium|8}}[Immediately decays into two alpha particles for a net reaction of 12N → 3 '''4He''' + e+.]
|-
| {{SimpleNuclide|Nitrogen|13}}
| style="text-align:right" | 7
| style="text-align:right" | 6
| {{val|13.00573861|(29)}}
| style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/7/13.pdf 1934]
| {{val|9.965|(4)|u=min}}
| β+
| '''{{SimpleNuclide|Carbon|13}}'''
| 1/2−
| [trace](/source/Trace_radioisotope)
|
|-
| {{SimpleNuclide|Nitrogen|14}}
| style="text-align:right" | 7
| style="text-align:right" | 7
| {{val|14.003074004251|(241)}}
| style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/7/14.pdf 1920]
| colspan=3 align=center|'''Stable'''
| 1+
| [{{val|0.99578}}, {{val|0.99663}}][Heaviest particle-bound isotope of nitrogen, see [Nuclear drip line](/source/Nuclear_drip_line)]
| rowspan=4 style="text-align:right" | 7
| rowspan=4 style="text-align:right" | 16
| rowspan=4|{{val|23.03942|(45)}}
| rowspan=4 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/7/23.pdf 1985]
| rowspan=4|{{val|13.9|(1.4)|u=ms}}
| β− (> {{val|46.6|(7.2)|u=%}})
| {{SimpleNuclide|Oxygen|23}}
| rowspan=4|1/2−#
| rowspan=4|
| rowspan=4|
|-
| β−n ({{val|42|(6)|u=%}})
| {{SimpleNuclide|Oxygen|22}}
|-
| β−2n ({{val|8|(4)|u=%}})
| {{SimpleNuclide|Oxygen|21}}
|-
| β−3n (< {{val|3.4|u=%}})
| {{SimpleNuclide|Oxygen|20}}
|-
| {{SimpleNuclide|Nitrogen|24}}
| style="text-align:right" | 7
| style="text-align:right" | 17
| {{val|24.05039|(43)}}#
| style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/7/24.pdf (2018)]
| < {{val|52|u=ns}}
| n ?
| {{SimpleNuclide|Nitrogen|23}} ?
|
|
|
|-id=Nitrogen-25
| rowspan=2|{{SimpleNuclide|Nitrogen|25}}
| rowspan=2 style="text-align:right" | 7
| rowspan=2 style="text-align:right" | 18
| rowspan=2|{{val|25.06010|(54)}}#
| rowspan=2 style="text-align:center" | [https://www.nndc.bnl.gov/discovery/abstracts/7/25.pdf (2018)]
| rowspan=2|< {{val|260|u=ns}}
| n ?
| {{SimpleNuclide|Nitrogen|24}} ?
| rowspan=2|1/2−#
| rowspan=2|
| rowspan=2|
|-
| 2n ?
| {{SimpleNuclide|Nitrogen|23}} ?
|-
{{Isotopes table/footer}}
==Nitrogen-13==
Nitrogen-13 (13N) has a [half-life](/source/half-life) of a little under ten minutes. It is produced in the atmosphere when [gamma ray](/source/gamma_ray)s (for example from [lightning](/source/lightning)) knock neutrons out of nitrogen-14.[{{cite journal |url=https://www.nature.com/news/lightning-makes-new-isotopes-1.23033 |title=Lightning makes new isotopes |last=Castelvecchi|first=Davide |date=November 22, 2017 |journal=Nature |doi=10.1038/nature.2017.23033 |access-date=November 29, 2017 |quote=|url-access=subscription }}]
13N decays to 13C, emitting a [positron](/source/positron). The positron quickly annihilates with an electron, producing two gamma rays of about {{val|511|u=keV}}. After a lightning bolt, this gamma radiation dies down with a half-life of 10 minutes, but these low-energy gamma rays go on average only about 90 metres through the air, so they may only be detected for a minute or so as the "cloud" of 13N and 15O floats by, carried by the wind.[{{cite journal|last1=Teruaki Enoto|display-authors=etal|title=Photonuclear reactions triggered by lightning discharge|journal=Nature|volume=551|issue=7681|pages=481–484|date=Nov 23, 2017|doi=10.1038/nature24630|pmid=29168803|bibcode=2017Natur.551..481E|arxiv=1711.08044|s2cid=4388159}}]
Nitrogen-13 plays a significant role in the [CNO cycle](/source/CNO_cycle), which is the dominant source of energy in [main sequence](/source/main_sequence) stars more massive than 1.5 times the [mass](/source/solar_mass) of the [Sun](/source/Sun).[{{cite book|author=Phillips, A.C. |title=The Physics of Stars |publisher=John Wiley & Sons |year=1994|isbn=0-471-94057-7}}
]
Nitrogen-13 is used in [positron emission tomography](/source/positron_emission_tomography) in the form of 13N-labelled ammonia, for example for [myocardial perfusion imaging](/source/myocardial_perfusion_imaging). It can be produced with a medical [cyclotron](/source/cyclotron), using a target of pure water with a trace amount of [ethanol](/source/ethanol). The reactants are oxygen-16 (present as H2O) and a proton, and the products are nitrogen-13 and an alpha particle (helium-4):
:{{chem2|^{1}H + ^{16}O -> ^{13}N + ^{4}He}}
In this [endothermic](/source/endothermic) reaction, the proton must be accelerated to have a total [energy](/source/energy) greater than 5.66 MeV.[{{cite journal |last1=Islam |first1=M. R. |last2=Beni |first2=M. S. |last3=Ng |first3=C |display-authors=et al. |date=2022 |title=Proton range monitoring using 13N peak for proton therapy applications |journal=PLOS ONE |volume=17 |issue=2 |pages=e0263521-1–e0263521-18 |doi=10.1371/journal.pone.0263521|pmid=35167589 |doi-access=free |pmc=8846528 |bibcode=2022PLoSO..1763521I }}] The presence of ethanol allows the formation of ammonia as nitrogen-13 is produced. Other routes of producing 13N-labelled ammonia exist, some of which facilitate co-generation of other light radionuclides for diagnostic imaging.[{{cite web | last1=Biricova | first1=Veronika | last2=Kuruc | first2= Jozef | title=Synthesis of the radiopharmaceuticals for positron emission tomography | url=https://www.osti.gov/etdeweb/servlets/purl/20895812 | date=2007 | publisher=U.S. Department of Energy, Office of Scientific and Technical Information | access-date=4 August 2022}}][{{cite journal | journal=EJNMMI Radiopharm Chem. | volume=5 | issue=11 | doi=10.1186/s41181-020-00097-7 | date=13 May 2020 | pmid=32405797 | last1=Yokell | first1=Daniel L. | last2=Rice |first2=Peter A. | last3=Neelamegam | first3=Ramesh | last4=El Fakhri | first4=Georges | title=Development, validation and regulatory acceptance of improved purification and simplified quality control of [13N] Ammonia | page=11 | doi-access=free | pmc=7221112 }}]
==Nitrogen-14==
Nitrogen-14 makes up the clear majority of natural nitrogen, about 99.62%, and is responsible for the Earth's stable atmosphere.
Nitrogen-14 is one of the very few [stable nuclides with both an odd number of protons and of neutrons](/source/Even_and_odd_atomic_nuclei) (seven each) and is the only one to make up a majority of its element. Unpaired protons or neutrons contribute a half-integer [nuclear spin](/source/Spin_(physics)), which in this case is a [spin 1/2](/source/spin_1%2F2) orbital, giving the nucleus a total magnetic [spin](/source/Spin_(physics)) of one (as the spins prefer to align).
The original source of nitrogen-14 and nitrogen-15 in the [Universe](/source/Universe) is believed to be [stellar nucleosynthesis](/source/stellar_nucleosynthesis), where they are produced as part of the [CNO cycle](/source/CNO_cycle).
Nitrogen-14 is the source of naturally occurring, radioactive, [carbon-14](/source/carbon-14). Some kinds of [cosmic radiation](/source/cosmic_radiation) cause a [nuclear reaction](/source/nuclear_reaction) with nitrogen-14 in the upper atmosphere of the Earth, creating carbon-14, which decays back to nitrogen-14 with a [half-life](/source/half-life) of {{val|5700|u=years}}.
==Nitrogen-15==
Nitrogen-15 is a rare stable [isotope](/source/isotope) of [nitrogen](/source/nitrogen), comprising about 0.38%. Nitrogen-15 presents one of the lowest thermal neutron capture cross sections of all isotopes.[{{cite web |url=http://www.nndc.bnl.gov/sigma/index.jsp?as=15&lib=endfb7.1&nsub=10 |title=Evaluated Nuclear Data File (ENDF) Retrieval & Plotting |publisher=National Nuclear Data Center}}]
Nitrogen-15 is frequently used in NMR ([Nitrogen-15 NMR spectroscopy](/source/Nitrogen-15_NMR_spectroscopy)). Unlike the more abundant nitrogen-14, which has an integer [nuclear](/source/atomic_nucleus) [spin](/source/Spin_(physics)) and thus a [quadrupole moment](/source/quadrupole_moment), 15N has a fractional [nuclear spin](/source/nuclear_spin) of one-half, which offers advantages for NMR such as narrower line width. As most nitrogen NMR studies look at a single nitrogen atom in an organic molecule, [isotopic labeling](/source/isotopic_labeling) is feasible.
[Nitrogen-15 tracing](/source/Nitrogen-15_tracing) is a technique used to study the [nitrogen cycle](/source/nitrogen_cycle).
==Nitrogen-16==
The radioisotope 16N is the dominant radioactivity source in the coolant water of [nuclear reactor](/source/nuclear_reactor)s cooled by water during normal operation. It is produced from 16O (in water) via an [(n,p) reaction](/source/Np_reaction), in which the 16O atom captures a neutron and expels a proton. It has a short half-life of 7.13 seconds, but its decay back to 16O produces high-energy [gamma radiation](/source/gamma_radiation) (6.13 MeV principal line[{{NNDC}}]).[{{Cite book|last=Neeb|first=Karl Heinz|title=The Radiochemistry of Nuclear Power Plants with Light Water Reactors|publisher=Walter de Gruyter|location=Berlin-New York|date=1997|isbn=978-3-11-013242-7|url=https://books.google.com/books?id=SJOE00whg44C&pg=PA227|page=227|access-date=2015-12-20|archive-date=2016-02-05|archive-url=https://web.archive.org/web/20160205191759/https://books.google.com/books?id=SJOE00whg44C&pg=PA227|url-status=live}}] Because of this, access to the primary coolant piping in a pressurised water reactor must be restricted during [reactor](/source/Nuclear_reactor) power operation.