[rob]

Dear All,

I am studying stereoisomers at the moment and bearing in mind the principles of distinguishing between  enantiomers, diasteoisomers, chiral/achiral ones, want to find out which applies to which for the following pairs of molecules. Could you give me any ideas  please. Thanks in advance.

[Albert]

Well, couple number 1 (top left) consists of two geometrical isomers: E and Z.

However, check this out: it helped me very much. http://www.cem.msu.edu/~reusch/VirtTxtJml/sterisom.htm#start