What is the difference between ionic and metallic bonding?

Ionic compounds are made up of charged atomic or molecular ions, the attraction between the oppositely charged ions holds the compound together. They don't conduct electricity, are soluble in water.

In metallic compounds, there are positively charged metal ions in a lattice which are surrounded by delocalised electrons. The strength of the bonding is dependent upon the number of electrons delocalised by each atom. Metallic compounds conduct electricity and are not soluble in (but some may react with) water.