A covalent bond consists of two non-metal atoms sharing electrons to give a full electron shell, they are held together by weak intermolecular forces.

Because they are non-metals, covalent compounds have low boiling points and because they do not form ions, they don't conduct electricity.

The example above shows a covalent bond between four hydrogen atoms and one carbon atom to form a methane molecule. The four hydrogen atoms altogether have four outer electrons with four outer electrons in carbon, they add up to eight outer electrons giving a full electron shell.