Closest-Packing GLY 4200 Lab 4 – Fall, 2014
Hexagonal Closest-Packing (HCP) • Third layer is directly over the first layer • Repeat is ABABAB…
Cubic Closest-Packing (CCP) • Third layer is distinct from the first two layers • Repeat is ABCABCABC….
Intralayer Voids • Space between the spheres, within the layer, is a trigonal planar void • A void is a space which may be occupied by a small ion, usually a cation
Void:Sphere Ratio • Ratio of voids/spheres • Around each sphere there are six voids • Around each void there are three spheres • The ratio of voids/spheres is therefore 2:1
Interlayer Voids • Both types of packing have empty places (voids) between layers • There are two types of voids • Each has a different CN
Assignment • Find out what types of voids are present • Find the ratio of voids/sphere for each type • Find the ratio of the voids to one another