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Aluminium

Pronunciation

• aluminium: /ˌæljʊˈmɪniəm/ (listen)
  (AL-yuu-MIN-ee-əm)

• aluminum: /əˈljuːmɪnəm/ (listen)
  (ə-LEW-mi-nəm)

Alternative namealuminum (U.S., Canada)

Appearancesilvery gray metallic

Standard atomic weight Ar, std(Al)26.9815384(3)[1]

Aluminium in the periodic table

HydrogenHelium

LithiumBerylliumBoronCarbonNitrogenOxygenFluorineNeon

SodiumMagnesiumAluminiumSiliconPhosphorusSulfurChlorineArgon

PotassiumCalciumScandiumTitaniumVanadiumChromiumManganeseIronCobaltNickelCopperZincGalliumGermaniumArsenicSeleniumBromineKrypton

RubidiumStrontiumYttriumZirconiumNiobiumMolybdenumTechnetiumRutheniumRhodiumPalladiumSilverCadmiumIndiumTinAntimonyTelluriumIodineXenon

CaesiumBariumLanthanumCeriumPraseodymiumNeodymiumPromethiumSamariumEuropiumGadoliniumTerbiumDysprosiumHolmiumErbiumThuliumYtterbiumLutetiumHafniumTantalumTungstenRheniumOsmiumIridiumPlatinumGoldMercury (element)ThalliumLeadBismuthPoloniumAstatineRadon

FranciumRadiumActiniumThoriumProtactiniumUraniumNeptuniumPlutoniumAmericiumCuriumBerkeliumCaliforniumEinsteiniumFermiumMendeleviumNobeliumLawrenciumRutherfordiumDubniumSeaborgiumBohriumHassiumMeitneriumDarmstadtiumRoentgeniumCoperniciumNihoniumFleroviumMoscoviumLivermoriumTennessineOganesson

B
↑
Al
↓
Ga

magnesium ← aluminium → silicon

Atomic number (Z)13

Groupgroup 13 (boron group)

Periodperiod 3

Block  p-block

Element categories, sometimes considered a metalloid

Electron configuration[Ne] 3s2 3p1

Electrons per shell2, 8, 3

Physical properties

Phase at STPsolid

Melting point933.47 K ​(660.32 °C, ​1220.58 °F)

Boiling point2743 K ​(2470 °C, ​4478 °F)

Density (near r.t.)2.70 g/cm3

when liquid (at m.p.)2.375 g/cm3

Heat of fusion10.71 kJ/mol

Heat of vaporization284 kJ/mol

Molar heat capacity24.20 J/(mol·K)

Vapor pressure

P (Pa)1101001 k10 k100 k

at T (K)148216321817205423642790

Atomic properties

Oxidation states−2, −1, +1,[2] +2,[3] +3 (an amphoteric oxide)

ElectronegativityPauling scale: 1.61

Ionization energies

• 1st: 577.5 kJ/mol

• 2nd: 1816.7 kJ/mol

• 3rd: 2744.8 kJ/mol

• (more)

Atomic radiusempirical: 143 pm

Covalent radius121±4 pm

Van der Waals radius184 pm

 

Spectral lines of aluminium

Other properties

Natural occurrenceprimordial

Crystal structure​face-centered cubic (fcc)

 

Speed of sound thin rod(rolled) 5000 m/s (at r.t.)

Thermal expansion23.1 µm/(m·K) (at 25 °C)

Thermal conductivity237 W/(m·K)

Electrical resistivity26.5 nΩ·m (at 20 °C)

Magnetic orderingparamagnetic[4]

Magnetic susceptibility+16.5·10−6 cm3/mol

Young's modulus70 GPa

Shear modulus26 GPa

Bulk modulus76 GPa

Poisson ratio0.35

Mohs hardness2.75

Vickers hardness160–350 MPa

Brinell hardness160–550 MPa

CAS Number7429-90-5

History

Namingfrom alumine, obsolete name for alumina

PredictionAntoine Lavoisier (1782)

DiscoveryHans Christian Ørsted (1824)

Named byHumphry Davy (1812[a])

Main isotopes of aluminium

Iso­topeAbun­danceHalf-life (t1/2)Decay modePro­duct

26Altrace7.17×105 yβ+26Mg

ε26Mg

γ–

27Al100%stable

 Category: Aluminium

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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. Aluminium has a great affinity towards oxygen, thanks to which it forms a protective layer of oxide on the surface. Aluminium visually resembles silver, both in color and in great ability to reflect light. Aluminium is soft, non-magnetic and ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of 26Al is used in radiodating.

Chemically, aluminium is a weak metal in the boron group; as it is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it is polarizing, and bonds aluminium forms tend towards covalency. The strong affinity towards oxygen leads to aluminium's common association with oxygen in nature in the form of oxides; for this reason, aluminium is found on Earth primarily in rocks in the crust, where it is the third most abundant element after oxygen and silicon, rather than in the mantle, and virtually never as the free metal.

The discovery of aluminium was announced in 1825 by Danish physicist Hans Christian Ørsted. The first industrial production of aluminium was initiated by French chemist Henri Étienne Sainte-Claire Deville in 1856. Aluminium became much more available to the public with the Hall–Héroult process developed independently by French engineer Paul Héroult and American engineer Charles Martin Hall in 1886, and the mass production of aluminium led to its extensive use in industry and everyday life. In World Wars I and II, aluminium was a crucial strategic resource for aviation. In 1954, aluminium became the most produced non-ferrous metal, surpassing copper. In the 21st century, most aluminium was consumed in transportation, engineering, construction, and packaging in the United States, Western Europe, and Japan.

Despite its prevalence in the environment, no living organism is known to use aluminium salts metabolically, but aluminium is well tolerated by plants and animals. Because of the abundance of these salts, the potential for a biological role for them is of continuing interest, and studies continue