MATHEMATICS OP PHYSICAL PROPERTIES OF CRYSTALS 



55 



Tetragonal system 

 .T3 is a four-fold 



axis 

 (Classes 9, 10 



& 13) 

 9 Constants 



Tetragonal system 

 .V3 is a four-fold axis 

 Xi is a binary axis 

 (Classes 11, 12, 14 & 

 . 15) 

 7 Constants 



TTll 



7ri2 





 



The m matrix 

 is entirely 

 analogous 



. .; (18.10) 



TTu 7ri2 TTis 



7I"12 TTll 7ri3 



TTai X31 7r33 



7r44 



X44 









 

 

 

 

 Tree 



The m matrix is entirely 

 analogous 



(18.11) 



Trigonal system 

 .V3 is a trigonal 



axis 

 (Classes 16 & 



17) 

 11 Constants 



TTll Xi2 7ri3 

 7ri2 TTll 7ri3 

 TTsi X31 TTsa 

 TTii Til 

 — 7r52 7r52 







TTu — 7r25 

 ■ Xi4 T25 







7r44 



■7r45 



TToB 







7r45 27r52 

 7r44 27r4l 

 TTu (tTii - 



■7ri2) 



The m matrix is analo- 

 gous except that 



W46 = W52 

 W56 = W41 



Wii — W12 



wzee = 



(18.12) 



Trigonal system 

 .T3 is a trigonal 



axis 

 -Ti is a binary axis 

 ■ (Classes 18, 20 & 



21) 

 8 Constants 



Hexagonal system 

 .T3 is a sixfold axis 

 Xi is a binary axis 

 (Classes 19, 22, 23, 

 24, 25, 26 & 27) 

 6 Constants 



Cubic system 

 3 Constants 



TTil 



Ti4 (tTu — 7ri2) 



The m matrix is analo- 

 gous except that 

 W56 = W41 



Wii — W12 



mee 



(quartz) 



(18.13) 



TTll 7ri2 7ri3 

 TTio TTu Xl3 

 TTsi TTsi 7r33 

 7r44 





 





 

 

 



7r44 



(vrn 



7ri2)^ 



The ni matrix is ana- 

 logous except that 

 Wu — mi2 



Wee = 



(18.14) 



TTu 7ri2 7ri2 



7ri2 TTll 7ri2 



'"'12 ^12 TTu 













 

 



7r44 

 7r44 







7r44 



The ni matrix is en- 

 tirely analogous 



(18.15) 



