Oxygen-22

Properties and data of the isotope ²²O.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Oxygen-22 is a radioisotope of the chemical element oxygen, which has 14 neutrons in its atomic nucleus in addition to the element-specific 8 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 22. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²²O is exclusively for academic purposes.

According to a report from 1969, the first observation and identification of the unstable nuclide was achieved in an transfer reaction by irradiating metallic thorium-232 with oxygen-18 atoms accelerated to 122 MeV [1].

See also: List of individual Oxygen isotopes (and general data sources).

General data

Name of the isotope:Oxygen-22; O-22Symbol:²²O or 228OMass number A:22 (= number of nucleons)Atomic number Z:8 (= number of protons)Neutrons N:14Isotopic mass:22.00997(6) u (atomic weight of Oxygen-22)Nuclide mass:22.0055814 u (calculated nuclear mass without electrons)Mass excess:9.287 MeVMass defect:0.17393908 u (per nucleus)Nuclear binding energy:162.02320939 MeV (per nucleus)
7.36469134 MeV (average binding energy per nucleon)Separation energy:S_N = 6.850(58) MeV (first neutron)
S_P = 23.238(146) MeV (first proton)Half-life:2.25(9) sDecay constant λ:0.3080654135822 s^-1Specific activity α:8.432787793939 × 10⁺²¹ Bq g^-1
227913183619.98 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Mirror nucleus:Silicon-22Year of discovery:1969

Radioactive Decay

Half-life T_½ = 2.25(9) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²²F	> 78 %	6.49(6) MeV
β^-, n	²¹F	< 22 %	1.259(57) MeV

Parent Nuclides

Direct parent isotopes are: ²²N, ²³N.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 14) and isobaric (same nucleon number A = 22) with Oxygen-22. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 14	Isobar A = 22
5	¹⁹B
6	²⁰C	²²C
7	²¹N	²²N
8	²²O	²²O
9	²³F	²²F
10	²⁴Ne	²²Ne
11	²⁵Na	²²Na
12	²⁶Mg	²²Mg
13	²⁷Al	²²Al
14	²⁸Si	²²Si
15	²⁹P
16	³⁰S
17	³¹Cl
18	³²Ar
19	³³K
20	³⁴Ca

External data and identifiers

Adopted Levels, Gammas:NuDat 22O

Literature and References

[1] - A. G. Artukh, G. F. Gridnev, V. L. Mikheev, V.V. Volkov:
New isotopes ²²O, ²⁰N and ¹⁸C produced in transfer reactions with heavy ions.
In: Nuclear Physics A, 137, 2, (1969), DOI 10.1016/0375-9474(69)90114-6.