Aluminium is a chemical element with the symbol Al and atomic number 13. It’s the most abundant metal in the Earth’s crust and the third most common element overall. This silvery-white, soft, non-magnetic, and ductile metal has become an integral part of our daily lives, from soda cans to spacecraft.
Aluminium’s Unique Properties Make It Indispensable
Aluminium’s low density – about one-third that of steel – makes it a go-to material for industries where weight matters. It’s why you’ll find it in everything from aircraft to bicycles. But don’t let its lightness fool you. When alloyed with other elements, aluminium can be as strong as some steels.
The metal’s affinity for oxygen is both a blessing and a curse. In air, aluminium quickly forms a thin oxide layer, which acts like a force field, protecting the metal from further corrosion. This self-healing property is why aluminium doesn’t rust like iron.
From Bauxite to Beverage Cans: Aluminium’s Journey
Aluminium doesn’t occur in its pure form in nature. Instead, we extract it from bauxite, a reddish-brown ore found mainly in tropical and subtropical regions. The journey from bauxite to aluminium is a two-step process:
- The Bayer process turns bauxite into alumina (aluminium oxide).
- The Hall-Héroult process uses electrolysis to break alumina down into pure aluminium.
This process is energy-intensive, which is why aluminium production often happens where electricity is cheap and plentiful.
Aluminium Alloys: Strength in Diversity
Pure aluminium is relatively soft, but mix it with other elements, and you’ve got a whole new ball game. Duralumin, an alloy of aluminium with copper, manganese, and magnesium, is as strong as soft steel but much lighter. It revolutionized aircraft design in the early 20th century.
Today, there are hundreds of aluminium alloys, each tailored for specific uses. Some are perfect for casting, others for machining, and some can even withstand the extreme conditions of spacecraft.
Recycling: Aluminium’s Superpower
Here’s a fun fact: aluminium is infinitely recyclable. Melting down used aluminium takes only 5% of the energy needed to produce new aluminium from ore. This recyclability makes aluminium a poster child for the circular economy.
Aluminium in Everyday Life
Look around, and you’ll spot aluminium everywhere:
- That soda can? Aluminium.
- The foil wrapping your leftovers? Aluminium.
- The frame of your bicycle? Probably aluminium.
- The body of your smartphone? Yep, aluminium.
Its versatility, coupled with its abundance, has made aluminium an irreplaceable part of modern life.
The Future is Light: Aluminium’s Role in Sustainability
As we push towards a more sustainable future, aluminium’s importance is only growing. Its light weight makes vehicles more fuel-efficient, its recyclability reduces waste, and its durability means products last longer.
From the device you’re reading this on to the buildings we live and work in, aluminium continues to shape our world in countless ways. It’s not just a metal – it’s a material that’s helping build a lighter, stronger, and more sustainable future.
Citations:
Aluminium (or aluminum in North American English) is a chemical element; it has symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has a great affinity towards oxygen, forming a protective layer of oxide on the surface when exposed to air. It visually resembles silver, both in its color and in its great ability to reflect light. It is soft, nonmagnetic, and ductile. It has one stable isotope, 27Al, which is highly abundant, making aluminium the 12th-most abundant element in the universe. The radioactivity of 26Al leads to it being used in radiometric dating.
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Aluminium | |||||||||||||||||||||||||
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Pronunciation |
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Alternative name | Aluminum (U.S., Canada) | ||||||||||||||||||||||||
Appearance | Silvery gray metallic | ||||||||||||||||||||||||
Standard atomic weightAr°(Al) | |||||||||||||||||||||||||
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Aluminium in the periodic table | |||||||||||||||||||||||||
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Atomic number (Z) | 13 | ||||||||||||||||||||||||
Group | group 13 (boron group) | ||||||||||||||||||||||||
Period | period 3 | ||||||||||||||||||||||||
Block | p-block | ||||||||||||||||||||||||
Electron configuration | [Ne] 3s2 3p1 | ||||||||||||||||||||||||
Electrons per shell | 2, 8, 3 | ||||||||||||||||||||||||
Physical properties | |||||||||||||||||||||||||
Phaseat STP | solid | ||||||||||||||||||||||||
Melting point | 933.47 K (660.32 °C, 1220.58 °F) | ||||||||||||||||||||||||
Boiling point | 2743 K (2470 °C, 4478 °F) | ||||||||||||||||||||||||
Density (at 20 °C) | 2.699 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
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Atomic properties | |||||||||||||||||||||||||
Oxidation states | common: +3 −2, −1, 0, +1, +2 | ||||||||||||||||||||||||
Electronegativity | Pauling scale: 1.61 | ||||||||||||||||||||||||
Ionization energies |
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Atomic radius | empirical: 143 pm | ||||||||||||||||||||||||
Covalent radius | 121±4 pm | ||||||||||||||||||||||||
Van der Waals radius | 184 pm | ||||||||||||||||||||||||
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Other properties | |||||||||||||||||||||||||
Natural occurrence | primordial | ||||||||||||||||||||||||
Crystal structure | face-centered cubic (fcc) (cF4) | ||||||||||||||||||||||||
Lattice constant | a = 404.93 pm (at 20 °C) | ||||||||||||||||||||||||
Thermal expansion | 22.87×10−6/K (at 20 °C) | ||||||||||||||||||||||||
Thermal conductivity | 237 W/(m⋅K) | ||||||||||||||||||||||||
Electrical resistivity | 26.5 nΩ⋅m (at 20 °C) | ||||||||||||||||||||||||
Magnetic ordering | paramagnetic | ||||||||||||||||||||||||
Molar magnetic susceptibility | +16.5×10−6 cm3/mol | ||||||||||||||||||||||||
Young's modulus | 70 GPa | ||||||||||||||||||||||||
Shear modulus | 26 GPa | ||||||||||||||||||||||||
Bulk modulus | 76 GPa | ||||||||||||||||||||||||
Speed of sound thin rod | (rolled) 5000 m/s (at r.t.) | ||||||||||||||||||||||||
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 | from alumine, obsolete name for alumina | ||||||||||||||||||||||||
Prediction | Antoine Lavoisier (1782) | ||||||||||||||||||||||||
Discovery | Hans Christian Ørsted (1824) | ||||||||||||||||||||||||
Named by | Humphry Davy (1812) | ||||||||||||||||||||||||
Isotopes of aluminium | |||||||||||||||||||||||||
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Chemically, aluminium is a post-transition metal in the boron group; as 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 has more polarizing power, and bonds formed by aluminium have a more covalent character. The strong affinity of aluminium for oxygen leads to the common occurrence of its oxides in nature. 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. It is obtained industrially by mining bauxite, a sedimentary rock rich in aluminium minerals.
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 the First and Second World Wars, 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 metabolize aluminium salts, but this 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 interest, and studies are ongoing.
English
Alternative forms
- aluminum (US, Canada, Philippines) (see § Usage notes below)