Al 13

Aluminum (Al)

post-transition-metal
Period: 3 Group: 13 Block: p

Solid

Standard Atomic Weight

26.981538 u

Electron configuration

[Ne] 3s2 3p1

Melting point

660.287 °C (933.437 K)

Boiling point

2518.85 °C (2792 K)

Density

2700 kg/m³

Oxidation states

−2, −1, 0, +1, +2, +3

Electronegativity (Pauling)

1.61

Ionization energy (1st)

Discovery year

1825

Atomic radius

125 pm

Details

Name origin Latin: alumen, aluminis, (alum).
Discovery country Denmark
Discoverers Hans Christian Oersted

Aluminum is a light, silvery post-transition metal and the most abundant metal in Earth’s crust. It is highly reactive thermodynamically, but a thin, adherent oxide film protects the metal from rapid corrosion in air and water. Its low density, electrical conductivity, formability, and alloying behavior make it one of the major structural and engineering metals.

Pure aluminum, a silvery-white metal, possesses many desirable characteristics. It is light, it is nonmagnetic and nonsparking, stands second among metals in the scale of malleability, and sixth in ductility.

The name derives from the Latin, alum and alumen for "stringent" because the early Romans called any substance with a stringent taste alum. The element was known in prehistoric times. In 1825, the Danish physicist, Hans Christian Oersted, isolated impure aluminium. The pure metal was first isolated by the German chemist Friedrich Wöhler in 1827.

Although aluminum is the most abundant metal in the earth's crust, it is never found free in nature. All of the earth's aluminum has combined with other elements to form compounds. Two of the most common compounds are alum, such as potassium aluminum sulfate (KAl(SO4)2·12H2O), and aluminum oxide (Al2O3). About 8.2% of the earth's crust is composed of aluminum. Scientists suspected than an unknown metal existed in alum as early as 1787, but they did not have a way to extract it until 1825. Hans Christian Oersted, a Danish chemist, was the first to produce tiny amounts of aluminum. Two years later, Friedrich Wöhler, a German chemist, developed a different way to obtain aluminum. By 1845, he was able to produce samples large enough to determine some of aluminum's basic properties. Wöhler's method was improved in 1854 by Henri Étienne Sainte-Claire Deville, a French chemist. Deville's process allowed for the commercial production of aluminum. As a result, the price of aluminum dropped from around $1200 per kilogram in 1852 to around $40 per kilogram in 1859. Unfortunately, aluminum remained too expensive to be widely used.

From the Latin word alumen, alum. The ancient Greeks and Romans used alum as an astringent and as a mordant in dyeing. In 1761 de Morveau proposed the name alumine for the base in alum, and Lavoisier, in 1787, thought this to be the oxide of a still undiscovered metal.

Friedrich Wohler is generally credited with having isolated the metal in 1827, although an impure form was prepared by Oersted two years earlier. In 1807, Davy proposed the name aluminium for the metal, undiscovered at that time, and later agreed to change it to aluminum. Shortly thereafter, the name aluminum was adopted to conform with the "ium" ending of most elements.

Aluminium was also the accepted spelling in the U.S. until 1925, at which time the American Chemical Society decided to use the name aluminum thereafter in their publications. See the Wikipedia entry on Aluminium for additional discussion on the spelling of this element.

Images

Properties

Physical

Atomic radius (empirical) 125 pm
Covalent radius 121 pm
Van der Waals radius 184 pm
Metallic radius 125 pm
Density
Molar volume 0.01 L/mol
Phase at STP solid
Melting point 660.287 °C
Boiling point 2518.85 °C
Thermal conductivity 237 W/(m·K)
Specific heat capacity 0.897 J/(g·K)
Molar heat capacity 24.2 J/(mol·K)
Crystal structure fcc

Chemical

Electronegativity (Pauling) 1.61
Electronegativity (Allen) 1.613
Electron affinity
Ionization energy (1st)
Ionization energy (2nd)
Ionization energy (3rd)
Ionization energy (4th)
Ionization energy (5th)
Oxidation states −2, −1, 0, +1, +2, +3
Valence electrons 3
Electron configuration
Electron configuration (semantic)

Thermodynamic

Critical point (temperature) 6427 °C
Heat of fusion 0.11100171 eV
Heat of vaporization 3.047106 eV
Heat of sublimation 3.382909 eV
Heat of atomization 3.382909 eV
Atomization enthalpy

Nuclear

Stable isotopes 1
Discovery year 1825

Abundance

Abundance (Earth's crust) 8.230e+4 mg/kg
Abundance (ocean)

Reactivity

N/A

Crystal Structure

Lattice constant a 405 pm

Electronic Structure

Electrons per shell 2, 8, 3

Identifiers

CAS number 7429-90-5
Term symbol
InChI InChI=1S/Al
InChI Key XAGFODPZIPBFFR-UHFFFAOYSA-N

Electron Configuration Measured

Ion charge
Protons 13
Electrons 13
Charge Neutral
Configuration Al: 3s² 3p¹
Electron configuration
Measured
[Ne] 3s² 3p¹
1s² 2s² 2p⁶ 3s² 3p¹
Orbital diagram
1s
2/2
2s
2/2
2p
6/6
3s
2/2
3p
1/6 1↑
Total electrons: 13 Unpaired: 1 ?

Atomic model

Protons 13
Neutrons 14
Electrons 13
Mass number 27
Stability Stable

Isotopes change neutron count, mass, and stability — not the electron configuration of a neutral atom.

Schematic atomic model, not to scale.

Atomic Fingerprint

Emission / Absorption Spectrum

25 / 50 (50 with intensity)
Measured
Emission Visible: 380–750 nm

Isotope Distribution

Monoisotopic element
Only naturally occurring isotope: 27 — 100.0000%
27100.0000%Mass numberNatural abundance (%)
Mass numberAtomic mass (u)Natural abundanceHalf-life
27 Stable26.98153853 ± 0.00000011100.0000%Stable
Measured

Phase / State

1 atm / 101.325 kPa
Solid 25 °C (298.15 K)

Reason: 635.3 °C below melting point (660.287 °C)

Melting point 660.287 °C
Boiling point 2518.85 °C
Below melting by 635.3 °C
0 K Current temperature: 25 °C 6000 K
Phase timeline

Schematic, not to scale

Solid
Liquid
Gas
Melting
Boiling
25°C
Solid
Liquid
Gas
Current

Phase transition points

Melting point Literature
660.287 °C
Boiling point Literature
2518.85 °C
Current phase Calculated
Solid

Transition energies

Heat of fusion Literature
0.11100171 eV

Energy required to melt 1 mol at melting point

Heat of vaporization Literature
3.047106 eV

Energy required to vaporize 1 mol at boiling point

Heat of sublimation Literature
3.382909 eV

Energy required to sublime 1 mol at sublimation point

Density

Reference density Literature
2700 kg/m³

At standard conditions

Current density Calculated
2700 kg/m³

At standard conditions

Advanced

Critical point Literature
6427 °C

Atomic Spectra

Showing 10 of 13 Atomic Spectra. Sorted by ion charge (ascending).

Lines Holdings ?

IonChargeTotal linesTransition probabilitiesLevel designations
Al I 0589322560
Al II +114299861429
Al III +2344259344
Al IV +3409123409
Al V +4600444600
Al VI +5515491515
Al VII +6350339350
Al VIII +7440418438
Al IX +8372339372
Al X +9189169189
NIST Lines Holdings →

Levels Holdings ?

IonChargeLevels
Al I 0192
Al II +1219
Al III +284
Al IV +3121
Al V +4158
Al VI +587
Al VII +673
Al VIII +795
Al IX +869
Al X +961
NIST Levels Holdings →
13 Al 26.9815385

Aluminum — Atomic Orbital Visualizer

[Ne]3s23p1
Energy levels 2 8 3
Oxidation states -2, -1, 0, +1, +2, +3
HOMO 3p n=3 · l=1 · m=-1
Aluminum — Atomic Orbital Visualizer Preview
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13 Al 26.9815385

Aluminum — Crystal Structure Visualizer

Face-Centered Cubic · Pearson cF4
Experimental
Pearson cF4
Coord. № 12
Packing 74.000%
Aluminum — Crystal Structure Visualizer Preview
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Ionic Radii

ChargeCoordinationSpinRadius
+34N/A39 pm
+35N/A48 pm
+36N/A53.5 pm

Compounds

Al
26.982 u
Al+3
26.982 u
Al
25.987 u
Al
28.980 u
Al
26.982 u
Al
27.982 u
Al+3
26.982 u

Isotopes (1)

Mass numberAtomic mass (u)Natural abundanceHalf-lifeDecay mode
27 Stable26.98153853 ± 0.00000011100.0000%Stable
stable
27 Stable
Atomic mass (u) 26.98153853 ± 0.00000011
Natural abundance 100.0000%
Half-life Stable
Decay mode
stable

Spectral Lines

Showing 50 of 341 Spectral Lines. Only spectral lines with measured intensity are shown by default.

Wavelength (nm)IntensityIon stageTypeTransitionAccuracySource
466.3046 nm1000Al IIemission3p2 1D → 3s.4p 1P*MeasuredNIST
559.33 nm800Al IIemission3s.4p 1P* → 3s.4d 1DMeasuredNIST
458.5818 nm500Al IIemission3s.4d 3D → 3s.7f 3F*MeasuredNIST
458.8199 nm400Al IIemission3s.4d 3D → 3s.7f 3F*MeasuredNIST
464.8609 nm400Al IIemission3s.4d 1D → 3s.10p 1P*MeasuredNIST
466.6799 nm400Al IIemission3s.5p 1P* → 3s.11s 1SMeasuredNIST
458.975 nm300Al IIemission3s.4d 3D → 3s.7f 3F*MeasuredNIST
444.7805 nm200Al IIemission3s.4d 1D → 3s.11p 1P*MeasuredNIST
458.968 nm200Al IIemission3s.4d 3D → 3s.7f 3F*MeasuredNIST
600.641 nm200Al IIemission3s.5p 3P* → 3s.7d 3DMeasuredNIST
390.0675 nm100Al IIemission3s.3p 1P* → 3p2 1DMeasuredNIST
528.3733 nm100Al IIemission3s.5p 3P* → 3s.8d 3DMeasuredNIST
561.329 nm100Al IIemission3s.4d 1D → 3s.7f 1F*MeasuredNIST
585.376 nm100Al IIemission3s.4d 3D → 3s.6f 3F*MeasuredNIST
624.337 nm100Al IIemission3s.4p 3P* → 3s.4d 3DMeasuredNIST
704.208 nm100Al IIemission3s.4s 3S → 3s.4p 3P*MeasuredNIST
747.141 nm90Al IIemission3s.3d 1D → 3s.4f 1F*MeasuredNIST
586.177 nm80Al IIemission3s.4d 3D → 3s.6f 3F*MeasuredNIST
597.197 nm80Al IIemission3s.5p 1P* → 3s.7d 1DMeasuredNIST
683.713 nm80Al IIemission3s.4p 3P* → 3s.5s 3SMeasuredNIST
623.175 nm75Al IIemission3s.4p 3P* → 3s.4d 3DMeasuredNIST
600.187 nm60Al IIemission3s.5p 3P* → 3s.7d 3DMeasuredNIST
422.6816 nm50Al IIemission3s.4d 3D → 3s.8f 3F*MeasuredNIST
422.7495 nm50Al IIemission3s.4d 3D → 3s.8f 3F*MeasuredNIST
422.7987 nm50Al IIemission3s.4d 3D → 3s.8f 3F*MeasuredNIST
586.79 nm50Al IIemission3s.4d 3D → 3s.6f 3F*MeasuredNIST
607.32 nm50Al IIemission3s.5p 3P* → 3s.8s 3SMeasuredNIST
622.619 nm50Al IIemission3s.4p 3P* → 3s.4d 3DMeasuredNIST
682.339 nm50Al IIemission3s.4p 3P* → 3s.5s 3SMeasuredNIST
705.671 nm50Al IIemission3s.4s 3S → 3s.4p 3P*MeasuredNIST
744.944 nm50Al IIemission3s.5p 1P* → 3s.6d 1DMeasuredNIST
399.5837 nm40Al IIemission3s.4d 3D → 3s.9f 3F*MeasuredNIST
450.371 nm40Al IVemission2s2.2p5.(2P*<3/2>).4s 2[3/2]* → 2s2.2p5.(2P*<3/2>).4p 2[5/2]MeasuredNIST
600.192 nm40Al IIemission3s.5p 3P* → 3s.7d 3DMeasuredNIST
399.6141 nm30Al IIemission3s.4d 3D → 3s.9f 3F*MeasuredNIST
450.237 nm30Al IVemission2s2.2p5.(2P*<1/2>).4s 2[1/2]* → 2s2.2p5.(2P*<1/2>).4p 2[3/2]MeasuredNIST
463.576 nm30Al IIemission3s.5p 3P* → 3s.10d 3DMeasuredNIST
528.5838 nm30Al IIemission3s.5p 1P* → 3s.8d 1DMeasuredNIST
606.112 nm30Al IIemission3s.5p 1P* → 3s.8s 1SMeasuredNIST
633.571 nm30Al IIemission3s.3d 1D → 3s.5p 1P*MeasuredNIST
399.6368 nm20Al IIemission3s.4d 3D → 3s.9f 3F*MeasuredNIST
402.6318 nm20Al IIemission3s.3d 1D → 3s.6p 1P*MeasuredNIST
446.894 nm20Al IVemission2s2.2p5.(2P*<3/2>).4s 2[3/2]* → 2s2.2p5.(2P*<3/2>).4p 2[3/2]MeasuredNIST
569.66 nm17Al IIIemission2p6.4s 2S → 2p6.4p 2P*MeasuredNIST
572.273 nm16Al IIIemission2p6.4s 2S → 2p6.4p 2P*MeasuredNIST
462.038 nm15Al IVemission2s2.2p5.(2P*<3/2>).4s 2[3/2]* → 2s2.2p5.(2P*<3/2>).4p 2[5/2]MeasuredNIST
531.6073 nm15Al IIemission3s.5p 3P* → 3s.9s 3SMeasuredNIST
452.919 nm14Al IIIemission2p6.4p 2P* → 2p6.4d 2DMeasuredNIST
451.257 nm13Al IIIemission2p6.4p 2P* → 2p6.4d 2DMeasuredNIST
669.6018 nm13Al Iemission3s2.4s 2S → 3s2.5p 2P*MeasuredNIST

Extended Properties

Covalent Radii (Extended)

Covalent radius (Pyykkö)  
Covalent radius (Pyykkö, double)  
Covalent radius (Pyykkö, triple)  
Covalent radius (Bragg)  

Van der Waals Radii

Truhlar  
Batsanov  
Alvarez  
UFF  
MM3  
Dreiding  

Atomic & Metallic Radii

Atomic radius (Rahm)  
Metallic radius (C12)  

Numbering Scales

Mendeleev
Pettifor
Glawe

Electronegativity Scales

Ghosh
Miedema
Gunnarsson–Lundqvist
Robles–Bartolotti

Polarizability & Dispersion

Dipole polarizability  
Dipole polarizability (unc.)  
C₆  
C₆ (Gould–Bučko)  

Miedema Parameters

Miedema molar volume  
Miedema electron density

Supply Risk & Economics

Production concentration
Relative supply risk
Reserve distribution
Political stability (top producer)
Political stability (top reserve)

Phase Transitions & Allotropes

Melting point933.47 K
Boiling point2792.15 K
Critical point (temperature)6700.15 K

Oxidation State Categories

+1 extended
−1 extended
0 extended
+2 extended
+3 main
−2 extended

Advanced Reference Data

Screening Constants (5)
nOrbitalσ
1s0.409
2p4.0366
2s4.7864
3p8.9344
3s8.8828
Crystal Radii Detail (3)
ChargeCNSpinrcrystal (pm)Origin
3IV53
3V62
3VI67.5from r^3 vs V plots,
Isotope Decay Modes (51)
IsotopeModeIntensity
21p
22B+100%
22B+p55%
222p1.1%
22B+A0%
23B+100%
23B+p1.2%
24B+100%
24B+A0%
24B+p0%
X‑ray Scattering Factors (504)
Energy (eV)f₁f₂
103.1199
10.16173.05822
10.32612.99776
10.49312.9385
10.66282.88041
10.83532.82347
11.01062.76766
11.18862.722
11.36962.69148
11.55352.66129

Additional Data

Sources

Sources of this element.

The method of obtaining aluminum metal by the electrolysis of alumina dissolved in cryolite was discovered in 1886 by Hall in the U.S. and at about the same time by Heroult in France. Cryolite, a natural ore found in Greenland, is no longer widely used in commercial production, but has been replaced by an artificial mixture of sodium, aluminum, and calcium fluorides.

Aluminum can now be produced from clay, but the process is not economically feasible at present. Aluminum is the most abundant metal to be found in the earth's crust (8.1%), but is never found free in nature. In addition to the minerals mentioned above, it is also found in granite and in many other common minerals.

References (1)

References

(9)
2 Atomic Mass Data Center (AMDC), International Atomic Energy Agency (IAEA)
Al

The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.

3 IUPAC Commission on Isotopic Abundances and Atomic Weights (CIAAW)
Aluminium

Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.

4 IUPAC Periodic Table of the Elements and Isotopes (IPTEI)

The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.

License note: Copyright (c) 2020 International Union of Pure and Applied Chemistry. The International Union of Pure and Applied Chemistry (IUPAC) contribution within Pubchem is provided under a CC-BY-NC-ND 4.0 license, unless otherwise stated.
5 Jefferson Lab, U.S. Department of Energy
Aluminum

Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/

License note: Please see citation and linking information: https://education.jlab.org/faq/index.html
6 Los Alamos National Laboratory, U.S. Department of Energy
Aluminum

The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.

7 NIST Physical Measurement Laboratory
Aluminum

The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database

8 PubChem Elements
Aluminum

This section provides all form of data related to element Aluminum.

9 PubChem Elements
Aluminum

The element property data was retrieved from publications.

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Data verified:

Content is reviewed against latest scientific data.