1. Crystals and Their Structure

3. Unit Cells in the Cubic Crystal System

4. Simple Cubic

5. Body - Centered Cubic

6. Face - Centered Cubic

7. Cubic Closest Packing of Frozen Methane
Cubic Closest Packing of Frozen Argon

9. Coordination Number

10. Counting Cell Occupancy

11. Volume of the Unit Cell L r The Pythagorean Theorem, of course!
r is the radius of an atom in the unit cell
The volume of the unit cell is L3
But how do you get L?
The Pythagorean Theorem, of course!

12. Volume of the Unit Cell L r L

13. Calculating Packing Efficiencyr L
Cell occupancy = 4
Packing efficiency is the ratio of the space occupied in the unit cell to the volume of the unit cell

14. Sodium Chloride

16. Crystalline and Amorphous Silicon Dioxide
Cristobalite, one of the crystalline
forms of silicon dioxide, shows
cubic closest packing.
A glass made from silicon
dioxide shows the amorphous
disoriented structure.

17. Xray Crystallography of Beryl The Old Days
Precession Camera

18. Xray Crystallography of BSA

19. STM of Silicon

20. STM of Gold
mikro/images/stm.gif 3/27/02

21. STM Images Xe atoms on Ni substrate
3/27/02

22. STM Images Carbon monoxide on Pt
3/27/02

23. STM Images Fe corral on Cu substrate
3/27/02