Close-packed structures

P. Krishna and D. Pandey*

Department of Physics, Banaras Hindu University, Varanasi, India

Teaching aims

To help towards an understanding of the way in which close packed structures may be described and begin to bridge the gap between theoretical abstractions of crystallography and the world of real crystals.

Level

It would be most appropriate in the later years of undergraduate courses, especially those in materials science. It could also form an element in a postgraduate course for newcomers to the subject.

Background

A general familiarity with cystal lattices, crystal symmetry, the regional lattice and the baisic principles of X-ray diffraction such as might be given in an introductory course is assumed.

Practical resources

Crystal structure models are essential in understanding the material in this article. An X-ray generator and rotation camera would be helpful.

Time required for teaching

It probably represents about 6 hours teaching if adequate use of models is to be made. Futher time for X-ray photgraphy of suitable single crystals of close packed structures would be an advantage.


* Now at the School of Materials Science and Technology, Banaras, Hindu University, India.