PIEZOELECTRIC CRYSTALS IN TENSOR FORM 



121 



Trigonal system, Z a 

 trigonal axis, X a 

 binary axis (Classes 

 18, 20, 21) 6 moduli 



Hexagonal system, Z a 

 sixfold axis, X a two- 

 fold axis (Classes 19, 

 22, 23, 24, 25, 26, 27) 

 5 moduli 



Cubic system (Classes 

 28, 29, 30, 31, 32) 3 

 moduli 



Isotropic bodies, 

 moduli 



Cl3 



Cu 

 Cn 



Cu — Ci4 







Cn 



C\1 

 C\3 





 



Cxi 



Cn 















Cn 



Cn 



Cn 



Cn 



Cn 



C\z 











Cn 



Cn 



Cn 















Cn 



Cn 



Cn 



Cn Cu 

 Cn — Cu 

 C33 



Cn 



Cn 



C3Z 















Cn 



Cn 



Cn 















Cn 



Cn 



Cn 







C44 

 









 

 



C44 

 





 

 

 



Cii 









 

 



Cn 





 

 

 

 

 Cn Cn 



















C44 





















 

 

 

 



^11 ~ Cn 



2 























Cn 



















Cn ~ Cn 











Cn — Cn 



The 5 tensor is 

 analogous ex- 

 cept that 556 = 



2^14 , Stt — 



2(511— 512) 



The 5 tensor is 

 analogous ex- 

 cept 566 = 

 2 (511 — 512) 



The 5 tensor is 

 entirely analo- 

 gous 



The . 5 tensor 

 analogous ex- 

 cept last three 

 diagonal terms 

 are 2 (511 — 512) 



