CH. V.] ASYMMETRIC CARBON ATOMS. 149 



still be superposed. In fact, no matter how the matches 



A 



Fig. 25. Two identical superposable models of the type Ca z bx. 



are changed about only one arrangement is possible. This 



Fig. 26. Model of an asymmetric carbon atom and its mirror image. 



is in agreement with the fact that only one modification 

 of the type Ca 2 bx exists. 



