Solid State Structures
JMol site http://firstyear.chem.usyd.edu.au/calculators/solid_state.shtml how common inorganic structures are built from the filling of interstitial sites in CCP and HCP lattices.
The site is used as post-work for a hands-on lab about packing (http://firstyear.chem.usyd.edu.au/LabManual/E12.pdf).