Aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

or ''aluminum'' (₁₃Al) has 22 known

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

s from ²²Al to ⁴³Al and 4 known

isomers In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. ...

. Only ²⁷Al (

stable isotope The term stable isotope has a meaning similar to stable nuclide, but is preferably used when speaking of nuclides of a specific element. Hence, the plural form stable isotopes usually refers to isotopes of the same element. The relative abundanc ...

) and ²⁶Al (

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consi ...

isotope, t_1/2 = ) occur naturally, however ²⁷Al comprises nearly all natural aluminium. Other than ²⁶Al, all radioisotopes have half-lives under 7 minutes, most under a second. The standard atomic weight is . ²⁶Al is produced from

argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as ...

in the atmosphere by spallation caused by

cosmic-ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...

protons. Aluminium isotopes have found practical application in dating marine

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

manganese nodule Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, de ...

s, glacial ice,

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

exposures, and meteorites. The ratio of ²⁶Al to ¹⁰Be has been used to study the role of sediment transport, deposition, and storage, as well as burial times, and erosion, on 10⁵ to 10⁶ year time scales. ²⁶Al has also played a significant role in the study of meteorites.

List of isotopes

, - , ²¹Al?This isotope has not yet been confirmed experimentally; given data is inferred or estimated from periodic trends. , style="text-align:right" , 13 , style="text-align:right" , 8 , 21.02898(64)# , <13 ns , p? , ²⁰Mg? , 5/2–# , , , - , rowspan=4, ²²Al , rowspan=4 style="text-align:right" , 13 , rowspan=4 style="text-align:right" , 9 , rowspan=4, 22.01954(43)# , rowspan=4, 91.1(5) ms , β⁺, p (55%) , ²¹Na , rowspan=4, (4)+ , rowspan=4, , rowspan=4, , - , β⁺ (43.862%) , ²²Mg , - , β⁺, 2p (1.1%) , ²⁰Ne , - , β⁺, α (0.038%) , ¹⁸Ne , - , rowspan=2, ²³Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 10 , rowspan=2, 23.0072444(4) , rowspan=2, 470(30) ms , β⁺ (99.54%) , ²³Mg , rowspan=2, 5/2+ , rowspan=2, , rowspan=2, , - , β⁺, p (0.46%) , ²²Na , - , rowspan=3, ²⁴Al , rowspan=3 style="text-align:right" , 13 , rowspan=3 style="text-align:right" , 11 , rowspan=3, 23.99994754(25) , rowspan=3, 2.053(4) s , β⁺ (99.9634%) , ²⁴Mg , rowspan=3, 4+ , rowspan=3, , rowspan=3, , - , β⁺, α (.035%) , ²⁰Ne , - , β⁺, p (.0016%) , ²³Na , - , rowspan=3 style="text-indent:1em" , ^24mAl , rowspan=3 colspan="3" style="text-indent:2em" , 425.8(1) keV , rowspan=3, 130(3) ms , IT (82.5%) , ²⁴Al , rowspan=3, 1+ , rowspan=3, , rowspan=3, , - , β⁺ (17.5%) , ²⁴Mg , - , β⁺, α (.028%) , ²⁰Ne , - , ²⁵Al , style="text-align:right" , 13 , style="text-align:right" , 12 , 24.99042831(7) , 7.183(12) s , β⁺ , ²⁵Mg , 5/2+ , , , - , rowspan=2 , ²⁶AlUsed in

radiodating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares ...

events early in the Solar System's history and meteorites , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 13 , rowspan=2 , 25.98689186(7) , rowspan=2 , 7.17(24)×10⁵ years , β⁺ (85%) , rowspan=2, ²⁶Mg , rowspan=2, 5+ , rowspan=2, Trace

cosmogenic Cosmogenic nuclides (or cosmogenic isotopes) are rare nuclides (isotopes) created when a high-energy cosmic ray interacts with the nucleus of an ''in situ'' Solar System atom, causing nucleons (protons and neutrons) to be expelled from the atom ...

, rowspan=2, , - , ε (15%) , - , style="text-indent:1em" , ^26mAl , colspan="3" style="text-indent:2em" , 228.306(13) keV , 6.3460(8) s , β⁺ , ²⁶Mg , 0+ , , , - , ²⁷Al , style="text-align:right" , 13 , style="text-align:right" , 14 , 26.98153841(5) , colspan="3" style="text-align:center;", Stable , 5/2+ , 1.0000 , , - , ²⁸Al , style="text-align:right" , 13 , style="text-align:right" , 15 , 27.98191009(8) , 2.245(5) min , β⁻ , ²⁸Si , 3+ , , , - , ²⁹Al , style="text-align:right" , 13 , style="text-align:right" , 16 , 28.9804532(4) , 6.56(6) min , β⁻ , ²⁹Si , 5/2+ , , , - , ³⁰Al , style="text-align:right" , 13 , style="text-align:right" , 17 , 29.982968(3) , 3.62(6) s , β⁻ , ³⁰Si , 3+ , , , - , rowspan=2, ³¹Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 18 , rowspan=2, 30.9839498(24) , rowspan=2, 644(25) ms , β⁻ (98.4%) , ³¹Si , rowspan=2, 5/2(+) , rowspan=2, , rowspan=2, , - , β⁻, n (1.6%) , ³⁰Si , - , rowspan=2, ³²Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 19 , rowspan=2, 31.988084(8) , rowspan=2, 33.0(2) ms , β⁻ (99.3%) , ³²Si , rowspan=2, 1+ , rowspan=2, , rowspan=2, , - , β⁻, n (.7%) , ³¹Si , - , style="text-indent:1em" , ^32mAl , colspan="3" style="text-indent:2em" , 955.7(4) keV , 200(20) ns , IT , ³²Al , (4+) , , , - , rowspan=2, ³³Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 20 , rowspan=2, 32.990878(8) , rowspan=2, 41.7(2) ms , β⁻ (91.5%) , ³³Si , rowspan=2, 5/2+ , rowspan=2, , rowspan=2, , - , β⁻, n (8.5%) , ³²Si , - , rowspan=2, ³⁴Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 21 , rowspan=2, 33.996779(3) , rowspan=2, 56.3(5) ms , β⁻ (74%) , ³⁴Si , rowspan=2, (4−) , rowspan=2, , rowspan=2, , - , β⁻, n (26%) , ³³Si , - , rowspan=2 style="text-indent:1em" , ^34mAl , rowspan=2 colspan="3" style="text-indent:2em" , 550(100)# keV , rowspan=2, 26(1) ms , β⁻ (70%) , ³⁴Si , rowspan=2, (1+) , rowspan=2, , rowspan=2, , - , β⁻, n (30%) , ³³Si , - , rowspan=2, ³⁵Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 22 , rowspan=2, 34.999760(8) , rowspan=2, 37.2(8) ms , β⁻ (62%) , ³⁵Si , rowspan=2, 5/2+# , rowspan=2, , rowspan=2, , - , β⁻, n (38%) , ³⁴Si , - , rowspan=2, ³⁶Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 23 , rowspan=2, 36.00639(16) , rowspan=2, 90(40) ms , β⁻ (70%) , ³⁶Si , rowspan=2, , rowspan=2, , rowspan=2, , - , β⁻, n (30%) , ³⁵Si , - , rowspan=2, ³⁷Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 24 , rowspan=2, 37.01053(19) , rowspan=2, 11.5(4) ms , β⁻ (71%) , ³⁷Si , rowspan=2, 5/2+# , rowspan=2, , rowspan=2, , - , β⁻, n (29%) , ³⁶Si , - , ³⁸Al , style="text-align:right" , 13 , style="text-align:right" , 25 , 38.0174(4) , 9.0(7) ms , β⁻ , ³⁸Si , , , , - , rowspan=2, ³⁹Al , rowspan=2 style="text-align:right" , 13 , rowspan=2 style="text-align:right" , 26 , rowspan=2, 39.02217(43)# , rowspan=2, 7.6(16) ms , β⁻, n (90%) , ³⁸Si , rowspan=2, 5/2+# , rowspan=2, , rowspan=2, , - , β⁻ (10%) , ³⁹Si , - , ⁴⁰Al , style="text-align:right" , 13 , style="text-align:right" , 27 , 40.02962(43)# , 10# ms 260 ns, β⁻ , ⁴⁰Si , , , , - , ⁴¹Al , style="text-align:right" , 13 , style="text-align:right" , 28 , 41.03588(54)# , 2# ms 260 ns, β⁻ , ⁴¹Si , 5/2+# , , , - , ⁴²Al , style="text-align:right" , 13 , style="text-align:right" , 29 , 42.04305(64)# , 1# ms 170 ns, β⁻ , ⁴²Si , , , , - , ⁴³Al , style="text-align:right" , 13 , style="text-align:right" , 30 , 43.05048(86)# , 1# ms 170 ns, β⁻ , ⁴³Si , , ,

Aluminium-26

Cosmogenic Cosmogenic nuclides (or cosmogenic isotopes) are rare nuclides (isotopes) created when a high-energy cosmic ray interacts with the nucleus of an ''in situ'' Solar System atom, causing nucleons (protons and neutrons) to be expelled from the atom ...

aluminium-26 Aluminium-26 (26Al, Al-26) is a radioactive isotope of the chemical element aluminium, decaying by either positron emission or electron capture to stable magnesium-26. The half-life of 26Al is 7.17 (717,000) years. This is far too short for the i ...

was first described in studies of the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

and meteorites. Meteorite fragments, after departure from their parent bodies, are exposed to intense cosmic-ray bombardment during their travel through space, causing substantial ²⁶Al production. After falling to Earth, atmospheric shielding protects the meteorite fragments from further ²⁶Al production, and its decay can then be used to determine the meteorite's terrestrial age. Meteorite research has also shown that ²⁶Al was relatively abundant at the time of formation of our planetary system. Most meteoriticists believe that the energy released by the decay of ²⁶Al was responsible for the melting and differentiation of some

asteroids An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

after their formation 4.55 billion years ago.

References

External links

Aluminum isotopes data from ''The Berkeley Laboratory Isotopes Project's''
{{Authority control Aluminium