Aluminium-29

Properties and data of the isotope ²⁹Al.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Aluminium-29 is a radioisotope of the chemical element aluminium, which has 16 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 29. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²⁹Al is exclusively for academic and experimental purposes.

The discovery of the neutron-rich isotope was reported in 1939. ²⁹Al was observed upon irradiation of a Mg template with 16MeV alpha particles [1]:

²⁶Mg(α,p)²⁹Al.

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

General data

Name of the isotope:Aluminium-29; Al-29Symbol:²⁹Al or 2913AlMass number A:29 (= number of nucleons)Atomic number Z:13 (= number of protons)Neutrons N:16Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.2307692307692 (= neutron-proton ratio)Neutron excess (N-Z):3Isotopic mass:28.9804532(4) u (atomic weight of Aluminium-29)Nuclide mass:28.9733217 u (calculated nuclear mass without electrons)Mass excess:-18.20773 MeVMass defect:0.259910872 u (per nucleus)Nuclear binding energy:242.1054178 MeV (per nucleus)
8.34846268 MeV (average binding energy per nucleon)Separation energy:S_N = 9.4284(3) MeV (first neutron)
S_P = 10.4768(4) MeV (first proton)Half-life:6.56(6) minDecay constant λ:0.0017610446660568 s^-1Specific activity α:3.787592514155 × 10⁺¹⁹ Bq g^-1
1023673652.4744 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2+Mirror nucleus:Sulfur-29Year of discovery:1939

Radioactive Decay

Half-life T_½ = 6.56(6) min (minutes) respectively 3.936 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	Details	γ energy (intensity)
β^-	²⁹Si	100 %	3.6873(3) MeV	β^-: 1.0237(6) MeV [89.9(3) %]	1.273361(9) MeV [91.26(6) %]

Parent Nuclides

Direct parent isotope is: ²⁹Mg.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 16) and isobaric (same nucleon number A = 29) with Aluminium-29. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 16	Isobar A = 29
5	²¹B
6	²²C
7	²³N
8	²⁴O
9	²⁵F	²⁹F
10	²⁶Ne	²⁹Ne
11	²⁷Na	²⁹Na
12	²⁸Mg	²⁹Mg
13	²⁹Al	²⁹Al
14	³⁰Si	²⁹Si
15	³¹P	²⁹P
16	³²S	²⁹S
17	³³Cl	²⁹Cl
18	³⁴Ar	²⁹Ar
19	³⁵K
20	³⁶Ca
21	³⁷Sc
22	³⁸Ti