Aluminum

Aluminum (Al)

Silvery-white lustrous metallic element of group 3 of the periodic table. Highly reactive but protected by a thin transparent layer of the oxide which quickly forms in air. There are many alloys of aluminum, as well as a good number of industrial uses. Makes up 8.1% of the Earth's crust, by weight. Isolated in 1825 by H.C. Oersted.
Atomic Number13
Atomic Weight26.9815385
Mass Number27
Group13
Period3
Blockp
Protons13 p+
Neutrons14 n0
Electrons13 e-
Aluminium-4.jpg Aluminium bar surface etched.jpg Animated Bohr Model of Al (Aluminum) Enhanced Bohr Model of Al (Aluminum) Bohr Model: Al (Aluminum) Orbital Diagram of Al (Aluminum)

Properties

Atomic Radius
125 pm
Molar Volume
Covalent Radius
126 pm
Metallic Radius
125 pm
Ionic Radius
39 pm
Crystal Radius
53 pm
Van der Waals Radius
184 pm
Density
2.7 g/cm³
Energy
Proton Affinity
Electron Affinity
0.43283 eV/particle
Ionization Energy
5.9857684 eV/particle
Heat of Vaporization
284.1 kJ/mol
Heat of Fusion
10.75 kJ/mol
Heat of Formation
330.9 kJ/mol
Electrons
Electron Shells2, 8, 3
Valence Electrons3
Electron Configuration[Ne] 3s2 3p1
Oxidation States-2, -1, 0, 1, 2, 3
Electronegativity
1.61
Electrophilicity
0.9274010094475963 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
2,792.15 K
Melting Point
933.473 K
Critical Pressure
Critical Temperature
6,700.15 K
Triple Point
Visual
Color
Silver
Appearancesilvery gray metallic
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
0.0000231 1/K
Molar Heat Capacity
Specific Heat Capacity
0.897 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
38 MS/m
Electrical Resistivity
0.000000026 m Ω
Superconducting Point
1.175 K
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.0000000078 m³/Kg
Magnetic Susceptibility (Molar)
0.00000000021 m³/mol
Magnetic Susceptibility (Volume)
0.0000211
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal StructureFace Centered Cubic (FCC)
Lattice Constant
4.05 Å
Lattice Anglesπ/2, π/2, π/2
Mechanical Properties
Hardness
2.75 MPa
Bulk Modulus
76 GPa
Shear Modulus
26 GPa
Young Modulus
70 GPa
Poisson Ratio
0.35
Speed of Sound
5,100 m/s
Classification
CategoryPost-transition metals, Poor metals
CAS GroupIIIB
IUPAC GroupIIIA
Glawe Number78
Mendeleev Number82
Pettifor Number80
Geochemical Classmajor
Goldschmidt Classlitophile
Other
Gas Basicity
Dipole Polarizability
57.8 ± 1 a₀
C6 Dispersion Coefficient
528 a₀
Allotropes
Neutron Cross Section
0.233
Neutron Mass Absorption
0.03
Quantum Numbers2P1/2
Space Group225 (Fm_3m)

Isotopes of Aluminum

Stable Isotopes1
Unstable Isotopes22
Radioactive Isotopes21

21Al

Abundance
Relative Atomic Mass
21.029082 ± 0.000644 Da
Mass Number21
G-Factor
Half Life
Spin5/2
Quadrupole Moment
Discovery Year
Parity+

21Al Decay Modes
Decay ModeIntensity
p (proton emission)%

22Al

AbundanceRadioactive ☢️
Relative Atomic Mass
22.01954 ± 0.00043 Da
Mass Number22
G-Factor
Half Life
91.1 ± 0.5 ms
Spin4
Quadrupole Moment
Discovery Year1982
Parity

22Al Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)55%
2p (2-proton emission)1.1%
β+α (β+-delayed α emission)0.038%

23Al

AbundanceRadioactive ☢️
Relative Atomic Mass
23.007244351 ± 0.00000037 Da
Mass Number23
G-Factor
1.556 ± 0.008
Half Life
446 ± 6 ms
Spin5/2
Quadrupole Moment
Discovery Year1969
Parity+

23Al Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)1.22%

24Al

AbundanceRadioactive ☢️
Relative Atomic Mass
23.999947598 ± 0.000000244 Da
Mass Number24
G-Factor
Half Life
2.053 ± 0.004 s
Spin4
Quadrupole Moment
Discovery Year1953
Parity+

24Al Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+α (β+-delayed α emission)0.035%
β+ p (β+-delayed proton emission)0.0016%

25Al

AbundanceRadioactive ☢️
Relative Atomic Mass
24.990428308 ± 0.000000069 Da
Mass Number25
G-Factor
1.45788 ± 0.00048
Half Life
7.1666 ± 0.0023 s
Spin5/2
Quadrupole Moment
0.24 ± 0.02
Discovery Year1953
Parity+

25Al Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

26Al

AbundanceRadioactive ☢️
Relative Atomic Mass
25.986891876 ± 0.000000071 Da
Mass Number26
G-Factor
0.5606 ± 0.0008
Half Life
717 ± 24 ky
Spin5
Quadrupole Moment
0.26 ± 0.03
Discovery Year1934
Parity+

26Al Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

27Al

Abundance
100
Relative Atomic Mass
26.981538408 ± 0.00000005 Da
Mass Number27
G-Factor
1.45628 ± 0.000008
Half Life
Spin5/2
Quadrupole Moment
0.1466 ± 0.001
Discovery Year1922
Parity+

28Al

AbundanceRadioactive ☢️
Relative Atomic Mass
27.981910009 ± 0.000000052 Da
Mass Number28
G-Factor
1.0803333333333 ± 0.0016666666666667
Half Life
2.245 ± 0.005 m
Spin3
Quadrupole Moment
0.172 ± 0.012
Discovery Year1934
Parity+

28Al Decay Modes
Decay ModeIntensity
β (β decay)100%

29Al

AbundanceRadioactive ☢️
Relative Atomic Mass
28.980453164 ± 0.00000037 Da
Mass Number29
G-Factor
Half Life
6.56 ± 0.06 m
Spin5/2
Quadrupole Moment
Discovery Year1939
Parity+

29Al Decay Modes
Decay ModeIntensity
β (β decay)100%

30Al

AbundanceRadioactive ☢️
Relative Atomic Mass
29.982969171 ± 0.000002077 Da
Mass Number30
G-Factor
1.004 ± 0.0023333333333333
Half Life
3.62 ± 0.06 s
Spin3
Quadrupole Moment
Discovery Year1961
Parity+

30Al Decay Modes
Decay ModeIntensity
β (β decay)100%

31Al

AbundanceRadioactive ☢️
Relative Atomic Mass
30.983949754 ± 0.0000024 Da
Mass Number31
G-Factor
1.5328 ± 0.002
Half Life
644 ± 25 ms
Spin5/2
Quadrupole Moment
0.134 ± 0.002
Discovery Year1971
Parity+

31Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)1.6%

32Al

AbundanceRadioactive ☢️
Relative Atomic Mass
31.988084338 ± 0.0000077 Da
Mass Number32
G-Factor
1.953 ± 0.002
Half Life
32.6 ± 0.5 ms
Spin1
Quadrupole Moment
0.0255 ± 0.0003
Discovery Year1971
Parity+

32Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)0.7%

33Al

AbundanceRadioactive ☢️
Relative Atomic Mass
32.990877685 ± 0.0000075 Da
Mass Number33
G-Factor
1.636 ± 0.002
Half Life
41.46 ± 0.09 ms
Spin5/2
Quadrupole Moment
0.141 ± 0.003
Discovery Year1971
Parity+

33Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)8.5%

34Al

AbundanceRadioactive ☢️
Relative Atomic Mass
33.996781924 ± 0.000002259 Da
Mass Number34
G-Factor
0.53925 ± 0.004
Half Life
53.73 ± 0.13 ms
Spin4
Quadrupole Moment
Discovery Year1977
Parity-

34Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)26%
2n (2-neutron emission)%

35Al

AbundanceRadioactive ☢️
Relative Atomic Mass
34.999759816 ± 0.0000079 Da
Mass Number35
G-Factor
Half Life
38.16 ± 0.21 ms
Spin5/2
Quadrupole Moment
Discovery Year1979
Parity+

35Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)35.8%
2n (2-neutron emission)%

36Al

AbundanceRadioactive ☢️
Relative Atomic Mass
36.006388 ± 0.0001605 Da
Mass Number36
G-Factor
Half Life
90 ± 40 ms
Spin
Quadrupole Moment
Discovery Year1979
Parity

36Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)31%
2n (2-neutron emission)%

37Al

AbundanceRadioactive ☢️
Relative Atomic Mass
37.010531 ± 0.0001935 Da
Mass Number37
G-Factor
Half Life
11.4 ± 0.3 ms
Spin5/2
Quadrupole Moment
Discovery Year1979
Parity+

37Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)52%
2n (2-neutron emission)1%

38Al

AbundanceRadioactive ☢️
Relative Atomic Mass
38.017681 ± 0.000161 Da
Mass Number38
G-Factor
0
Half Life
9 ± 0.7 ms
Spin0
Quadrupole Moment
0
Discovery Year1989
Parity-

38Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)84%
2n (2-neutron emission)%

39Al

AbundanceRadioactive ☢️
Relative Atomic Mass
39.02307 ± 0.000322 Da
Mass Number39
G-Factor
Half Life
7.6 ± 1.6 ms
Spin5/2
Quadrupole Moment
Discovery Year1989
Parity+

39Al Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)97%
2n (2-neutron emission)%

40Al

AbundanceRadioactive ☢️
Relative Atomic Mass
40.03094 ± 0.000322 Da
Mass Number40
G-Factor
Half Life
Spin
Quadrupole Moment
Discovery Year1996
Parity

40Al Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

41Al

AbundanceRadioactive ☢️
Relative Atomic Mass
41.037134 ± 0.000429 Da
Mass Number41
G-Factor
Half Life
Spin5/2
Quadrupole Moment
Discovery Year1997
Parity+

41Al Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

42Al

AbundanceRadioactive ☢️
Relative Atomic Mass
42.045078 ± 0.000537 Da
Mass Number42
G-Factor
Half Life
Spin
Quadrupole Moment
Discovery Year2007
Parity

42Al Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

43Al

AbundanceRadioactive ☢️
Relative Atomic Mass
43.05182 ± 0.000644 Da
Mass Number43
G-Factor
Half Life
Spin5/2
Quadrupole Moment
Discovery Year2007
Parity+

43Al Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

History

In 1761, Guyton de Morveau proposed the name alumine for the base in alum, and Antoine Lavoisier, in 1787, thought this to be the oxide of a still undiscovered metal. Sir Humphry Davy identified the existence of a metal base of alum in 1808. Hans Christian Ørsted was the first to isolate metallic aluminum in 1825 in impure form. Friedrich Wöhler is generally credited with having isolated the metal in 1827. From the Latin word alumen, alum

DiscoverersHans Christian Oersted
Discovery LocationDenmark
Discovery Year1825
Etymology (Name Origin)Latin: alumen, aluminis, (alum).
Pronunciationah-LOO-men-em (English)
Aluminum is not known to be toxic
Aluminum does not stick to magnets under normal conditions

Uses

Aluminum is used in an extensive range of products from drinks cans to window frames and boats to aircraft. It is used in electrical transmission lines. It is also used for kitchen utensils, outside building decoration, and in thousands of industrial applications. When alloyed with small amounts of copper, magnesium, silicon, manganese, or other elements impart a variety of useful properties. Used for many purposes from airplanes to beverage cans. Too soft in its pure form so less than 1% of silicon or iron is added, which hardens and strengthens it.

Sources

Never occurs in free form. Obtained by electrolysis from bauxite (Al2O3).

Abundance
Abundance in Earth's crust
82,300 mg/kg
Abundance in Oceans
0.002 mg/L
Abundance in Human Body
0.00009 %
Abundance in Meteor
0.91 %
Abundance in Sun
0.006 %
Abundance in Universe
0.005 %

Nuclear Screening Constants

1s0.409
2p4.0366
2s4.7864
3p8.9344
3s8.8828