Explain 2-fold Axis of Symmetry, etc.

[pgalatin at gems.vcu.edu]

In article <45i7uh$iak at saba.info.ucla.edu>, Kathy Weidman <kweidman at ucla.edu> writes:
> Could someone please explain the difference between a 2-fold axis of 
> symmetry, a 3-fold and a 4-fold.  Please give examples if possible.
> 
> Thank you very much for your help.

The way I understand the x-fold concept:

An n-fold axis symmetry is an axis that projects through the object of choice, 
such that when you rotate the object by increments of 360/n degrees about the 
axis, it "appears" the same. By "appearing", that most often means that you
achieve maximum values of a correlation function (such as a Patterson function
correlation )... 

Peter S. Galatin
M.D./Ph.D. Program (Medicinal Chemistry)
Medical College of Virginia
Richmond, VA