Aluminum or Aluminium Facts

Chemical & Physical Properties

Aluminum Metal (Penny to Show Scale)
Aluminum Metal (Penny to Show Scale). USGS

Aluminum Basic Facts:

Symbol: Al
Atomic Number: 13
Atomic Weight:26.981539
Element Classification Basic Metal
CAS Number: 7429-90-5

Aluminum Periodic Table Location

Group: 13
Period: 3
Block: p

Aluminum Electron Configuration

Short Form: [Ne]3s23p1
Long Form: 1s22s22p63s23p1
Shell Structure: 2 8 3

Aluminum Discovery

History: Alum (potassium aluminum sulfate- KAl(SO4)2) has been used since ancient times. It was used in tanning, dyeing, and as an aid to stop minor bleeding and even as an ingredient in baking powder.

In 1750, German chemist Andreas Marggraf found a technique to produce a new form of alum without the sulfur. This substance was called alumina, which is known as aluminum oxide (Al2O3) today. Most contempory chemists of the time believed alumina was an 'earth' of an previously unknown metal. Aluminum metal was finally isolated in 1825 by Danish chemist Hans Christian Ørsted (Oersted). German chemist Friedrich Wöhler attempted unsuccessfully to reproduce Ørsted's technique and found an alternate method that also produced metallic aluminum two years later. Historians differ on who should receive credit for the discovery.
Name: Aluminum derives its name from alum. The Latin name for alum is 'alumen' meaning bitter salt.
Note on Naming: Sir Humphry Davy proposed the name aluminum for the element, however, the name aluminium was adopted to conform with the "ium" ending of most elements. This spelling is in use in most countries.

Aluminium was also the spelling in the U.S. until 1925, when the American Chemical Society officially decided to use the name aluminum instead.

Aluminum Physical Data

State at room temperature (300 K): Solid
Appearance: soft, light, silvery white metal
Density: 2.6989 g/cc
Density at Melting Point: 2.375 g/cc
Specific Gravity: 7.874 (20 °C)
Melting Point: 933.47 K, 660.32 °C, 1220.58 °F
Boiling Point: 2792 K, 2519 °C, 4566 °F
Critical Point: 8550 K
Heat of Fusion: 10.67 kJ/mol
Heat of Vaporization: 293.72 kJ/mol
Molar Heat Capacity: 25.1 J/mol·K
Specific Heat: 24.200 J/g·K (at 20 °C)

Aluminum Atomic Data

Oxidation States (Bold most common): +3, +2, +1
Electronegativity: 1.610
Electron Affinity: 41.747 kJ/mol
Atomic Radius: 1.43 Å
Atomic Volume: 10.0 cc/mol
Ionic Radius: 51 (+3e)
Covalent Radius: 1.24 Å
First Ionization Energy: 577.539 kJ/mol
Second Ionization Energy: 1816.667 kJ/mol
Third Ionization Energy: 2744.779 kJ/mol

Aluminum Nuclear Data

Number of isotopes: Aluminum has 23 known isotopes ranging from 21Al to 43Al. Only two occur naturally. 27Al is the most common, accounting for nearly 100% of all natural aluminum. 26Al is nearly stable with a half-life of 7.2 x 105 years and is only found in trace amounts naturally.

Aluminum Crystal Data

Lattice Structure: Face-Centered Cubic
Lattice Constant: 4.050 Å
Debye Temperature: 394.00 K

Aluminum Uses

Ancient Greeks and Romans used alum as an astringent, for medicinal purposes, and as a mordant in dyeing. It is used in kitchen utensils, exterior decorations, and thousands of industrial applications. Although the electrical conductivity of aluminum is only about 60% that of copper per area of cross section, aluminum is used in electrical transmission lines because of its light weight. The alloys of aluminum are used in the construction of aircraft and rockets.

Reflective aluminum coatings are used for telescope mirrors, making decorative paper, packaging, and many other uses. Alumina is used in glassmaking and refractories. Synthetic ruby and sapphire have applications in producing coherent light for lasers.

Miscellaneous Aluminum Facts

  • Aluminum is the 3rd most abundant element in the Earth's crust.
  • Aluminum was once called the "Metal of Kings" because pure aluminum was more expensive to produce than gold until the Hall-Heroult process was discovered.
  • Aluminum is the most widely used metal after iron.
  • The primary source of aluminum is the ore bauxite.
  • Aluminum is paramagnetic.
  • The top three countries that mine aluminum ore are Guinea, Australia and Vietnam. Australia, China and Brazil lead the world in aluminum production.
  • The IUPAC adopted the name aluminium in 1990 and in 1993 recognized aluminum as an acceptable option for the element's name.
  • Aluminum requires a lot of energy to separate from its ore. Recycling aluminum only requires only 5% of that energy to produce the same amount.
  • Aluminum can be 'rusted' or oxidized by mercury.
  • Rubies are aluminum oxide crystals where some aluminum atoms have been replaced by chromium atoms.
  • A piece of jewelry in the tomb of the 3rd Century Chinese general Chou-Chu has been found to contain 85% aluminum. Historians do not know how the ornament was produced.
  • Aluminum is used in fireworks to make produce sparks and white flames. Aluminum is a common component of sparklers.

References: CRC Handbook of Chemistry & Physics (89th Ed.), National Institute of Standards and Technology, History of the Origin of the Chemical Elements and Their Discoverers, Norman E. Holden 2001.

Return to the Periodic Table

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