Giant Lattices (Edexcel A Level Chemistry): Revision Note

Giant Lattices

Ionic Lattices

• The ions form a lattice structure which is an evenly distributed crystalline structure

• Ions in a lattice are arranged in a regular repeating pattern so that positive charges cancel out negative charges

• The attraction between the cations and anions is occurring in all directions

  • Each ion is attracted to all of the oppositely charged ions around it

• Therefore the final lattice is overall electrically neutral

Ionic solids are arranged in lattice structures

Metallic Lattices 

• Metals form giant metallic lattices in which the metal ions are surrounded by a ‘sea’ of delocalised electrons

• The metal ions are often packed in hexagonal layers or in a cubic arrangement

• This layered structure with the delocalised electrons gives a metal its key properties

Layers of copper ions (the delocalised electrons are not shown in the diagram)

Covalent lattices

• Covalent bonds are bonds between nonmetals in which electrons are shared between the atoms

• Covalent compounds can be arranged in simple molecular or giant molecular lattices

  • Simple molecular lattices: iodine, buckminsterfullerene (C₆₀) and ice

  • Giant molecular: silicon(IV) oxide, graphite and diamond

Simple molecular lattices

Giant molecular lattices