1. Objective By the end of this section you should be able to draw a simple crystal structure projection

2. Crystal Structure Projections Another way of describing structures Make drawings of a structure projected down one axis onto a unit cell face b a ORIGIN

3. Procedure Decide which plane to use Draw scaled, labelled picture of plane Take coordinates and plot e.g. cubic system - plot any plane, say ab Label origin and x and y axes Plot points in x and y Label each height, z Remember to include atoms at all edges and corners i.e., an atom at (0,0,0) should also be at (1,0,0) (0,1,0) and (0,0,1) (i.e. remember the next unit cell along) b a ORIGIN

4. Example 1 - Rocksalt

5. Try Examples

6. Example 2 - Zinc Blende (Sphalerite)

7. Example 3 - Fluorite structure