From Wikipedia, the free encyclopedia
This article is about the metallic element. For other uses, see Aluminium (disambiguation).
Aluminium, 13Al
Aluminium-4.jpg
General properties
Pronunciation
UK: /ˌæljʊˈmɪniəm/ (About this sound listen)
AL-yuu-MIN-ee-əm
US: /əˈluːmɪnəm/ (About this sound listen)
ə-LOO-min-əm
Alternative name aluminum (U.S., Canada)
Appearance silvery gray metallic
Standard atomic weight (Ar, standard) 26.9815385(7)[1]
magnesium ← aluminium → silicon
Atomic number (Z) 13
Group, period group 13 (boron group), period 3
Block p-block
Element category post-transition metal, sometimes considered a metalloid
Electron configuration [Ne] 3s2 3p1
Electrons per shell
2, 8, 3
Physical properties
Phase (at STP) solid
Melting point 933.47 K (660.32 °C, 1220.58 °F)
Boiling point 2743 K (2470 °C, 4478 °F)
Density (near r.t.) 2.70 g/cm3
when liquid (at m.p.) 2.375 g/cm3
Heat of fusion 10.71 kJ/mol
Heat of vaporization 284 kJ/mol
Molar heat capacity 24.20 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1482 1632 1817 2054 2364 2790
Atomic properties
Oxidation states +3, +2,[2] +1[3], −1, −2 (an amphoteric oxide)
Electronegativity Pauling scale: 1.61
Ionization energies
1st: 577.5 kJ/mol
2nd: 1816.7 kJ/mol
3rd: 2744.8 kJ/mol
(more)
Atomic radius empirical: 143 pm
Covalent radius 121±4 pm
Van der Waals radius 184 pm
Color lines in a spectral range
Spectral lines
Miscellanea
Crystal structure face-centered cubic (fcc) Face-centered cubic crystal structure for aluminium
Speed of sound thin rod (rolled) 5000 m/s (at r.t.)
Thermal expansion 23.1 µm/(m·K) (at 25 °C)
Thermal conductivity 237 W/(m·K)
Electrical resistivity 28.2 nΩ·m (at 20 °C)
Magnetic ordering paramagnetic[4]
Magnetic susceptibility +16.5·10−6 cm3/mol
Young's modulus 70 GPa
Shear modulus 26 GPa
Bulk modulus 76 GPa
Poisson ratio 0.35
Mohs hardness 2.75
Vickers hardness 160–350 MPa
Brinell hardness 160–550 MPa
CAS Number 7429-90-5
History
Naming after alumina (aluminium oxide), itself named after mineral alum
Prediction Antoine Lavoisier (1782)
Discovery and first isolation Hans Christian Ørsted (1824)
Named by Humphry Davy (1812)
Main isotopes of aluminium
Isotope Abundance Half-life (t1/2) Decay mode Product
26Al trace 7.17×105 y β+ 26Mg
ε 26Mg
γ –
27Al 100% stable
view talk edit | references | in Wikidata
Aluminium or aluminum is a chemical element with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal in the boron group. By mass, aluminium makes up about 8% of the Earth's crust; it is the third most abundant element after oxygen and silicon and the most abundant metal in the crust, though it is less common in the mantle below. The chief ore of aluminium is bauxite. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals.[5]
Aluminium is remarkable for its low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the aerospace industry[6] and important in transportation and building industries, such as building facades and window frames.[7] The oxides and sulfates are the most useful compounds of aluminium.[6]
Despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals.[8] Because of these salts' abundance, the potential for a biological role for them is of continuing interest, and studies contin
