[ 647 ] 



LXIII. The Crystalline Structure of Zinc Oxide. By 

 W. Lawrence Bragg, M.A., Langworthy Professor of 

 Physics. Man cli ester I ?n i re rsity * . 



ZINC oxide crystallizes in jthe hexagonal system. The 

 crystals are o£ the dihexagonal polar type, with an 

 axial ratio a:c = l:l*608. Natural crystals of zinc oxide, 

 or zincite, are rare, and the material used for this investigation 

 consisted of a platy mass of zincite of irregular shape. The 

 direction of the cleavage and etching of the surface showed 

 that the mass was composed of crystals which were very 

 nearly parallel in their orientation. By noting the direction 

 of the facets produced by etching it was possible to grind 

 surfaces on the material which were approximately parallel 

 to the principal faces of the cry stab The basal plane (0001), 

 the first-order prism face (lOlO), the second-order prism face 

 (1120), and the pyramid face (10ll) were prepared in 

 this way. 



The reflexions from these faces of the X-rays from an 

 anticathode of palladium were examined with the X-ray 

 spectrometer f, and the results are shown in fig. 1. 



Fie. 1. 



















{oooi} 









1 



. 







{,oio} 





G°32' 



1 



I 



1 



1 1 





{»*>} 





6*0' 











{.Oil} 





1 



l0 o 30' 









{oooi} 

 {,oio} 



a-58 ----->; 

 A.U. 



A.U 



6-33} 









| 



<--- 



2-80 - > 



A.U. 







| 



ZnO ZnO ZnO Z.nO ZnO 2nO 



I ! 



ZnO ZnO ZnO 2nO 



Arrangement of Planes. 



6 U 45 10 20 



Olanc/ny anyle, for wave length 0584 A.U 



The structure assigned to the crystal by these results is 

 shown by fig. 2. the positions of the centres of the zinc and 



* Communicated by the Author. 



t W. JH. Bragg and W. L. Bragg, Proc. Roy. Soc. A. vol. lxxxviii. 

 April 1913. 



