Neon-21

Properties and data of the isotope ²¹Ne.

Contents

General Data

Parent Nuclides

NMR Data

Isotones und Isobares

Literature

Neon-21 is a radioisotope of the chemical element neon, which has 11 neutrons in its atomic nucleus in addition to the element-specific 10 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 21.

²¹Ne is one of the three stable isotopes that make up the natural Ne gas on earth, accounting for 0.27%. The discovery was reported in 1928: Neon was used for calibration in experiments on the ionization of Methane gas. The mass spectrographic analysis showed a small peak, the cause of which could be attributed to the presence of neon-21 [1].

General data

Name of the isotope:Neon-21; Ne-21Symbol:²¹Ne or 2110NeMass number A:21 (= number of nucleons)Atomic number Z:10 (= number of protons)Neutrons N:11Isotopic mass:20.9938467(3) u (atomic weight of Neon-21)Nuclide mass:20.9883609 u (calculated nuclear mass without electrons)Mass excess:-5.73176 MeVMass defect:0.179717696 u (per nucleus)Nuclear binding energy:167.40595552 MeV (per nucleus)
7.97171217 MeV (average binding energy per nucleon)Separation energy:S_N = 6.76116(4) MeV (first neutron)
S_P = 13.00328(5) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)3/2+Magnetic dipole moment:μ(μ_N) = -0.6617774(10)Charge radius:2.9695(33) femtometer fmMirror nucleus:Sodium-21Year of discovery:1928

Parent Nuclides

Direct parent isotopes are: ²¹F, ²¹Na.

Occurrence

Comparison of the natural Neon isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Neon Isotopic mixture	20.1797 u	100 %
Isotope ²⁰Ne	19.99244018(2) u	90.48(3) % [88.47 - 90.51 %]	stable	0+
Isotope ²¹Ne	20.9938467(3) u	0.27(1) %	stable	3/2+
Isotope ²²Ne	21.9913851(2) u	9.25(3) %	stable	0+

NMR data

Nuclear magnetic properties of the NMR active Nuclide ²¹Ne

Isotope:²¹Ne-NMRQuantity:0.27(1) %Spin:3/2+Nuclearmagnetic moment
μ/μ_N:-0.6617774(10)Gyromagnetic ratio γ:- 2.11308 · 10⁷ rad T^-1 s^-1Nuclear g-factor:g_l = -0.44118493333333Quadrupole moment Q:+ 0.10155(75) barn (100 fm²)Resonance frequency:v₀ = 3.3631 at 1 TFrequency ratio:Ξ(²¹Ne) = 7.894296 %Relative Sensitivity:0.00246 (H₀ = const.)
0.3949 (v₀ = const.)
[related to ¹H = 1.000]Reference compound:
(conditions)Enriched ²¹neon gas under pressure (1.1 MPa).

Of the three naturally occurring neon isotopes, neon-21 is the only NMR-active nuclide. However, due to the low frequency of quadrupolar noble gas of 0.27% in the element neon (corresponding test samples must be enriched), ²¹Ne NMR is a rather rarely used special application. In addition, Ne is chemically inert and only produces small NMR signals.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 11) and isobaric (same nucleon number A = 21) with Neon-21. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 11	Isobar A = 21
4	¹⁵Be
5	¹⁶B	²¹B
6	¹⁷C	²¹C
7	¹⁸N	²¹N
8	¹⁹O	²¹O
9	²⁰F	²¹F
10	²¹Ne	²¹Ne
11	²²Na	²¹Na
12	²³Mg	²¹Mg
13	²⁴Al	²¹Al
14	²⁵Si
15	²⁶P
16	²⁷S
17	²⁸Cl

Data changes (history)

External data and identifiers

Adopted Levels, Gammas:NuDat 21Ne

Literature and References

[1] - T. R. Hogness, H. M. Kvalnes:
The Ionization Processes in Methane Interpreted by the Mass Spectrograph.
In: Physical Review, 32, 942, (1928), DOI 10.1103/PhysRev.32.942.

[2] - R. Bijker, F. Iachello:
Cluster structure of ²¹Ne and ²¹Na.
In: Nuclear Physics A, 1010, 122193, (2021), DOI 10.1016/j.nuclphysa.2021.122193.

[3] - Włodzimierz Makulski, Piotr Garbacz:
Gas-phase ²¹Ne NMR studies and the nuclear magnetic dipole moment of neon-21.
In: Magnetic Resonance in Chemistry, MRC, 58, 7, (2020), DOI 10.1002/mrc.5006.