Transition metals

Most metals are transition metals. They include iron and other metals used in construction, gold and other precious metals. The transition metals are placed in the central part of the periodic table.

Period table with the transition metals in red.The transition metals are placed between groups 2 and 3 in the periodic table

Typical properties

Compared to other metals, the transition metals have these typical properties:

Remember that these are typical properties - some transition metals may not show one or more of them. For example:

  • mercury melts at just -39°C, so it is a liquid at room temperature
  • scandium has a similar density to aluminium in group 3, so pieces of scandium are relatively lightweight

Iron as a transition metal

Iron (Fe) has the typical properties of transition metals.

High melting point and density

The table shows the melting point and density of iron, compared to three non-transition metals. Iron, a transition metal, has a higher melting point and a higher density than the non-transition metals.

MetalMelts atDensityPosition
Iron1538°C7.87 g/cm3Transition metals
Sodium98°C0.97 g/cm3Group 1
Magnesium650°C1.74 g/cm3Group 2
Aluminium660°C2.70 g/cm3Group 3

Coloured compounds

Metals that are not transition metals usually form white or colourless compounds. Like other transition metals, iron forms coloured compounds. The table shows some examples of these.

CompoundColour
Iron(II) hydroxide, Fe(OH)2Pale green
Iron(III) hydroxide, Fe(OH)3Orange-brown
Iron(III) oxide, Fe2O3Red-brown

Catalytic activity

Catalysts are substances that speed up the rate of reaction without being used up in the reaction. Iron is the catalyst used to make ammonia in the Haber process. Iron(III) oxide is a catalyst used to make hydrogen by reacting carbon monoxide and steam together.