Periodic Table


Atomic number: 13
Atomic weight: 26.981538
Symbol: Al
Group number: 13
Electronic configuration: [Ne].3s2.3p1


Pure aluminium is a silvery-white metal with many desirable characteristics. It is light, nontoxic (as the metal), nonmagnetic and nonsparking. It is somewhat decorative. It is easily formed, machined, and cast. Pure aluminium is soft and lacks strength, but alloys with small amounts of copper, magnesium, silicon, manganese, and other elements have very useful properties.

Aluminium is an abundant element in the earth's crust, but it is not found free in nature. The Bayer process is used to refine aluminium from bauxite, an aluminium ore.

General information

Discoveror: Hans Christian Oersted
Date discovered: 1825
Discovered at: Denmark
Meaning of name: From the Latin word "alumen" meaning "alum"

Physical data

Standard state: solid at 298 K
Colour: silvery
Density of solid at ambient temperature/kg m-3: 2700
Molar volume/cm3: 10.00

Radii /pm

Atomic: 118
Covalent (single bond):
Pauling radius for the ion [Al]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius111.0142.2no datano data


Both values are quoted on the Pauling scale.

Pauling: 1.61
Allred Rochow: 1.47

Crystal Structure

structure: ccp (cubic close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.


Temperatures (/K)

melting point: 933.47
boiling point: 2792

Enthalpies /kJ mol-1

fusion: 10.7
vaporization: 294

single bond enthalpies:
Al-F Al-Cl Al-Br Al-I Al-Al
583 421 no data no data 186.2

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
27Al26.9815386 (8)100

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/Al.html