120 BEl 



Rhombic System 



(Classes 6, 7 and 8) 

 9 moduli 



Tetragonal system, Z 

 a fourfold axis (Classes 

 9, 10, 13) 7 moduli 



Tetragonal system, Z a 

 fourfold axis, X a two- 

 fold axis (Classes 11, 

 12, 14, 15) 6 moduli 



Trigonal system, Z a 

 twofold axis, (Classes 

 16, 17) 7 moduli 



