Giant Covalent Structures

Covalent bonding forms substances with different structures and properties. For example:

  • Small molecules (e.g. O2 and NH3) – Contain a limited number of non-metal atoms held together by strong covalent bonds.
  • Giant covalent substances – Contain a much larger number of non-metal atoms covalently bonded together.

Properties of Giant Covalent Structures

Melting and boiling points

Substances with giant covalent structures are solid at room temperature and have high melting and boiling points. This is due to the large number of strong covalent bonds, which make it difficult to break the bonds and convert the solid into a liquid or gas. Breaking these bonds requires a large amount of energy.

Electrical conductivity

Most giant covalent substances do not conduct electricity, as they do not contain free electrons or charged particles. However, there are exceptions such as graphite and graphene, which are excellent conductors of electricity.

Silicon Dioxide

One of the most common examples of a giant covalent structure is silicon dioxide, also known as silica. It is the main component of sand and is formed by covalent bonds between silicon and oxygen atoms. This means that there are many strong covalent bonds in silicon dioxide, which contribute to its high melting and boiling point.

It requires a large amount of energy to break these bonds and turn silicon dioxide into a liquid or gas form.

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