MATHEMATICS OF PHYSICAL PROPERTIES OF CRYSTALS 

 A rotation of 60° about .V3: 



67 



I 



^4o 



2 2 



2 2 

 1 



To form a substitute 

 — s/S for s/s in a. 



VS \/3 







4 4 



A rotation of 60° about .V3 combined with a reflection in .V3 



1 3' 



0^ 

 2 



0^ 



2 

 



1 



2 







(21.11) 



1^ 



2 2 



^ 1 



2 2 



0-1 



To form a substitute 

 — ■\/3 for \/3 in a. 



L rotation of 120° about X3: 



4 

 1 











- 







Vs] 



2 



V3 



2 











0- 



VS \/3 







_i Vs 

 2 2 



^-1 



2 2 



00 -^ 

 2 



1 \/3 



2 

 V3 



2-2« 

 1 



To form a substitute 



— -y/S for y/s in a. 







1 





 



VJ 

 2 



_ 1 

 2 







V3l 

 2 



V3 

 2 

 







.(21.12) 



(21.13) 



