• Most ionic, metallic and covalent compounds are?crystalline lattice
• The ions, atoms or molecules are arranged in a?regular and repeating arrangement

Giant ionic lattices

• An?ionic bond?is an electrostatic force between a positively charged metal (cation) ion and a negatively charged non-metal (anion) ion
  • The metal becomes positively charged as it transfers electrons to the non-metal becomes negatively charged
• Ionic compounds are arranged in giant?ionic lattices?(also called?giant ionic structures)
• The type of lattice formed depends on the sizes of the?positive?and?negative?ions which are arranged in an?alternating?fashion
  • The ionic lattice of MgO and NaCl are?cubic

Ionic lattices of the ionic compounds NaCl and MgO

General ionic lattice which shown the actual packing of the ions

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

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

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