Learning outcomes - after studying this topic, you should be able to:

• define and give examples of alloys
• show how close packing of spheres can lead to hexagonal or cubic close packing
• identify the major metal structures - cubic close packed, hexagonal close packed, body centred cubic and simple cubic
• list the coordination number, packing efficiency and number of atoms in the unit cell of each of these packing types
• identify unit cells for cubic packing
• relate the unit cell contents and the stoichiometry
• calculate the packing efficiency in cubic unit cells
• rationalize the structure of simple ionic solids in terms of filling of the holes in the close packed structures

• Section 7.4 (in Blackman, Bottle, Schmid, Mocerino and Wille, Chemistry, 3^rd Edition, 2015 (John Wiley))

• Crystal lattice (in ChemWiki)
• Unit cell (in ChemWiki)
• Virtual: crystal structure (in ChemWiki)
• Solids (in Wikibooks General Chemistry)
• Ionic bonding (in Wikibooks General Chemistry)

Crystal Structures Contributed by Adam Bridgeman

Interactive 3D crystal structures Tags: unit cell | ccp | hcp Contributed by Adam Bridgeman

Caesium chloride unit cell Description: Video showing how the crystal structure is built from the unit cell and how atoms on the corners end up being shared Tags: CsCl | unit cells | crystal structures Contributed by Adam Bridgeman

Sodium chloride unit cell Description: Video showing how the crystal structure is built from the unit cell and how atoms on the corners, faces and edges end up being shared Tags: FCC | unit cells | crystal structures | rocksalt Contributed by Adam Bridgeman

Coordination numbers Description: Video tutorial and lots of examples on coordination numbers in covalent molecules, complexes, metallic solids and ionic compounds Tags: coordination number | complexes | crystal structures Contributed by Adam Bridgeman