Solids can be divided into two main types.

Crystalline solids: which have a highly regular, repeating pattern in their structure.

Amorphous solids: don’t have a regular, repeating pattern in their structure. Amorphous comes from the Greek for ‘without shape’. Some people say they are not solids, but just super cooled liquids. Examples include glass, rubber, and several plastics

Network Solids

Molecular Solids

Metallic Solids

Ionic Solids

The properties of pure metals can be modified by adding atoms of other elements to their crystalline structure. A mixture of elements that retains the properties of metals is called an alloy.

Two types of alloys are;

Substitutional alloys have some of the host metal atoms replaced by other metal atoms of similar size.

E.g. Brass, sterling silver, pewter

Interstitial alloys have some of the small holes in the structure occupied by small atoms.

E.g. Steel

Many atomic solids form strong covalent solids. Carbon and silicon and their compounds form important network solids.

They are usually brittle, non-conductive of heat or electricity