254 



PHENOMENA, ATOMS, AND MOLECULES 



of these ways. I have used the word isomorphism as expressing a close 

 resemblance in crystallographic data. The data given in the cases of the 

 nitrates and chlorates show conclusively in my mind that the formation of 



A. Monoclinic. 



CuTiF6.4H20 



CuCbOFt,.4H20..... 

 CuW02F4.4H,0 



B. Monoclinic. 



KsHSnFg 



KsHCbOF; 



C. Orthorhombic. 



KzSnCU.zHzO 



KiFeCU-HaO 



D. Monoclinic. 



MnClii.4H20 



BeNa2F4 



E. Tetragonal. 



YPO4 



ZrSi04 



Sn204..,. 



F. Tetragonal. 



KIO4 



CaWOi ;,.. 



KOsOsN .^ 



KRUO4... 



\ G. Orthorhombic^ 



KCIO4 



BaS04 



KBF4. 



H. Orthorhombic. 



K2SO4.... 



K2BeF4 ) 



[N(CH3)4].HgCl4.... 

 Znl2.4NHs 



I. Monoclinic. 



(NH4)2Se04 



CS2Hgl4 



0.7471 

 0.7627 

 0.7648 



0.6277 

 0.6279 



0.6852 

 0.691 I 



I 1525 

 0.9913 



0.7817 

 0.8152 

 0.7898 



0.5727 

 0.5708 

 0.5766 

 0.5754 



1.8900 



I -3155 



(the cleavage is the same) 



J. Trigonal. 



NaNOa 



CaCOs...... .-.. 



K. 



Albite NaAlSisOg 



Anorthite CaAl2Si208. 



0.5564 

 0.5629 

 o.562g^ 



0.4928 

 0.4900 



0.7586 

 0.7178 



0.6445 

 0.6929 



0.6177 



0.640 



0.6726 



1-5534 

 1.5268 

 I. 6319 

 1.6340 



I .2792 

 1-3136 

 I .2830 



0.7418 



0.7395 

 0.7893 

 0.7922 



1:1987 

 0.9260 



0.8297 

 0.854 



104° 9 

 103° 20' 

 1-05° .14-' 



93" 

 93" 14' 



99° 25' 

 99° 20' 



"5 29 

 110° 4' 



Are closely isomorphous. 



crystals often occurs when there is no close resemblance in crystal struc- 

 ture. It seems therefore that this criterion should not be used to indicate 

 similarity in chemical constitution. The question of course arises: how 



