Aluminium-23

Properties and data of the isotope ²³Al.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Aluminium-23 is a radioisotope of the chemical element aluminium, which has 10 neutrons in its atomic nucleus in addition to the element-specific 13 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 23. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²³Al is exclusively for academic purposes.

The proton-rich isotope was first described in 1939 [1]; aluminium-23 was created by irradiating silicon-containing materials with 54.7 MeV protons according to the following nuclear reaction:

²⁸Si(p,⁶He)²³Al.

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

General data

Name of the isotope:Aluminium-23; Al-23Symbol:²³Al or 2313AlMass number A:23 (= number of nucleons)Atomic number Z:13 (= number of protons)Neutrons N:10Isotopic mass:23.0072444(4) u (atomic weight of Aluminium-23)Nuclide mass:23.0001129 u (calculated nuclear mass without electrons)Mass excess:6.74812 MeVMass defect:0.181130176 u (per nucleus)Nuclear binding energy:168.72167216 MeV (per nucleus)
7.33572488 MeV (average binding energy per nucleon)Separation energy:S_N = 19.525(40) MeV (first neutron)
S_P = 0.1409(4) MeV (first proton)Half-life:446(6) msDecay constant λ:1.5541416604483 s^-1Specific activity α:4.069243476311 × 10⁺²² Bq g^-1
1099795534138.2 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2+Magnetic dipole moment:μ(μ_N) = +3.89(22)Quadrupole moment Q:0.16(5) barn (100 fm²)Nuclear g-factor:g_l = 1.556Mirror nucleus:Neon-23Year of discovery:1969

Radioactive Decay

Half-life T_½ = 446(6) ms respectively 4.46 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	²³Mg	98.06 %	12.2217(3) MeV
β⁺, p	²²Na	1.04(3) %

Parent Nuclides

Direct parent isotope is: ²³Si.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 10) and isobaric (same nucleon number A = 23) with Aluminium-23. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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

External data and identifiers

Adopted Levels, Gammas:NuDat 23Al

Literature and References

[1] - Joseph Cerny et al.:
New Nuclides ¹⁹Na and ²³Al Observed via the (p,⁶He) reaction.
In: Physical Review Letters, 22, 612, (1969), DOI 10.1103/PhysRevLett.22.612.