Al

Al
Name	Aluminum
Atomic number	13
Caption	Crystal structure of Aluminium
Category	Post-transition metal
Atomic mass	26.9815385
Appearance	Silvery-gray metal
Phase	Solid
Melting point	660.32 °C
Boiling point	2519 °C
Density	2.70 g/cm³
Electron configuration	[Ne] 3s2 3p1

Al

Aluminium is a silvery-gray, lightweight metal with atomic number 13 and symbol Al. It is a widely used post-transition metal notable for its low density, high electrical and thermal conductivity, and corrosion resistance due to a native oxide film. Aluminium figures prominently in industries associated with Bauxite mining, Hall–Héroult process smelting, and fabrication for Aerospace engineering, Automotive industry, and Packaging.

Etymology and naming

The element's English name derives from alum, a term for compounds known since antiquity and linked to Pliny the Elder and Dioscorides. The modern name stabilized during the 19th century after disputes involving Sir Humphry Davy, who proposed names such as "alumium" and "aluminum" alongside contemporaries in Royal Society discussions. Variants of the name persist between American English and British English, reflecting divergent editorial standards exemplified by publications such as Oxford English Dictionary and Webster's Dictionary.

Physical and chemical properties

Aluminium crystallizes in a face-centered cubic lattice and exhibits metallic bonding consistent with its electron configuration [Ne] 3s2 3p1, yielding a trivalent oxidation state predominantly as Al3+. Its low density (≈2.70 g/cm³) and high strength-to-weight ratio are exploited in structural applications linked to Wright brothers-era innovations and modern Boeing airframes. Aluminium forms a thin, adherent oxide layer, aluminium oxide (Al2O3), which confers corrosion resistance relevant to Olympic torch construction and Eiffel Tower maintenance. It alloyed with elements such as Copper, Magnesium, Silicon, Zinc, and Lithium to produce series of alloys standardized by bodies like ASM International and used in contexts ranging from Formula One to International Space Station components. Electrically, aluminium's conductivity is lower than copper by volume but competitive by weight, influencing choices in Power transmission and High-voltage transmission infrastructures.

Occurrence and production

Aluminium is the most abundant metallic element in the Earth's crust, present in minerals such as Gibbsite, Boehmite, and Diaspore within Bauxite deposits found in regions like Australia, Guinea, Brazil, and Jamaica. Primary production begins with the Bayer process to refine bauxite into alumina, followed by electrolytic reduction in the Hall–Héroult process in large Smelter facilities often located near hydroelectric power sources exemplified by plants in Iceland and Canada. Historical developments in production involved industrialists and inventors such as Charles Martin Hall and Paul Héroult, whose patents reshaped industrial chemistry and influenced corporations like Alcoa and Rio Tinto. Alternative production routes under research include carbothermic reduction and electrolytic technologies pursued by organizations including Alcoa, Rio Tinto, and research groups at Massachusetts Institute of Technology and Imperial College London.

Applications and uses

Aluminium and its alloys serve in structural, thermal, electrical, and chemical applications. In Aerospace engineering, alloys such as the 2000, 6000, and 7000 series are used by manufacturers like Airbus and Boeing for fuselage and wing structures. In Automotive industry, aluminium reduces vehicle mass in products from Ford Motor Company and BMW, aiding compliance with regulations such as Corporate Average Fuel Economy standards. In Construction, aluminium cladding, windows, and roofing systems are supplied by firms like Arconic and Vulcan Materials Company. Other uses include Packaging foil and cans by companies like Ball Corporation, electrical conductors in PowerGrid infrastructure, Heat exchangers in HVAC systems, and cookware and consumer goods by brands such as Tefal and Le Creuset. Aluminium compounds like Aluminium sulfate and Aluminium chloride are used in water treatment and chemical synthesis relevant to institutions such as American Water Works Association.

Biological role and health effects

Aluminium is not known to have a biological role in humans or most organisms; it is considered a nonessential element. Environmental and clinical research institutions including World Health Organization and European Food Safety Authority have assessed exposure from dietary sources, pharmaceuticals, and occupational inhalation. High occupational exposure in industries affiliated with Bauxite mining and aluminium smelting has been associated with respiratory conditions monitored by agencies such as Occupational Safety and Health Administration. Controversies and studies involving neurodegenerative diseases prompted investigations by researchers at Harvard University and University College London, but consensus statements from bodies like Institute of Medicine caution that causal links remain unproven. Regulatory limits for aluminium in drinking water and food additives are set by organizations including WHO and EFSA.

Environmental impact and recycling

Primary aluminium production is energy-intensive and associated with greenhouse gas emissions, including perfluorocarbons when operated under certain electrolytic conditions; industry responses include carbon-reduction initiatives by companies like Rio Tinto and Alcoa and policies under frameworks such as the Paris Agreement. Bauxite mining affects landscapes and biodiversity in regions governed by authorities like Queensland Government and Guinean government, prompting remediation and best-practice standards advocated by International Aluminium Institute. Aluminium is highly recyclable with closed-loop systems employed by manufacturers and recyclers including Novelis and Sims Metal Management, saving substantial energy compared with primary production and supporting circular economy goals discussed at forums such as United Nations Environment Programme initiatives.

Category:Chemical elements