Aluminium

Aluminium or aluminum (Symbol Al) (see the spelling section below) is a silvery and ductile member of the poor metal group of chemical elements. Its atomic number is 13. Aluminium is found primarily as the ore bauxite and is remarkable for its resistance to oxidation (due to the phenomenon of passivation), its strength, and its light weight. Aluminium is used in many industries to make millions of different products and is very important to the world economy. Structural components made from aluminium are vital to the aerospace industry and very important in other areas of transportation and building in which light weight, durability, and strength are needed.

Isotopes

Aluminium has nine isotopes, whose mass numbers range from 23 to 30. Only Al-27 (stable isotope) and Al-26 (radioactive isotope, t1/2 = 7.2 × 105 y) occur naturally, however Al-27 has a natural abundance of 100%. Al-26 is produced from argon in the atmosphere by spallation caused by cosmic-ray protons. Aluminium isotopes have found practical application in dating marine sediments, manganese nodules, glacial ice, quartz in rock exposures, and meteorites. The ratio of Al-26 to beryllium-10 has been used to study the role of transport, deposition, sediment storage, burial times, and erosion on 105 to 106 year time scales.

Related Topics:
Isotope - Stable isotope - Radioactive - ''t''_1/2 - Y - Argon - Atmosphere - Spallation - Cosmic-ray - Proton - Marine - Manganese - Quartz - Rock - Meteorite - Beryllium - Sediment

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Cosmogenic Al-26 was first applied in studies of the Moon and meteorites. Meteorite fragments, after departure from their parent bodies, are exposed to intense cosmic-ray bombardment during their travel through space, causing substantial Al-26 production. After falling to Earth, atmospheric shielding protects the meteorite fragments from further Al-26 production, and its decay can then be used to determine the meteorite's terrestrial age. Meteorite research has also shown that Al-26 was relatively abundant at the time of formation of our planetary system. Possibly, the energy released by the decay of Al-26 was responsible for the remelting and differentiation of some asteroids after their formation 4.6 billion years ago.

Related Topics:
Cosmogenic - Moon - Differentiation - Asteroids

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Clusters

In the journal Science of 14 January 2005 it was reported that clusters of 13 aluminium atoms (Al13) had been made to behave like an iodine atom; and, 14 aluminium atoms (Al14) behaved like an alkaline earth atom. The researchers also bound 12 iodine atoms to an Al13 cluster to form a new class of polyiodide. This discovery is reported to give rise to the possibility of a new characterisation of the periodic table: "cluster elements". The research teams were led by Shiv N. Khanna (Virginia Commonwealth University) and A. Welford Castleman Jr (Penn State University). http://www.science.psu.edu/alert/Castleman1-2005.htm

Related Topics:
Science - 14 January - 2005 - Iodine - Alkaline earth - Periodic table - Cluster elements - Shiv N. Khanna - Virginia Commonwealth University - A. Welford Castleman Jr - Penn State University

~ ~ ~ ~ ~ ~ ~ ~ ~ ~