( '^8 ) 



I obtained some crystals of" BenzijlplUal-lso-imide ^) melting point 

 82°, 5. As both isomeric compounds are, structurallj, closely related, 

 I thought it a matter of importance to investigate their crystallogra- 

 phical symmetry. 



a). Benzylphtalimide. (m.p. 11572°)- 



From a mixture of ether and alcohol I obtained this compound 

 in large, very transparent and lustrous crystals of a somewhat 

 rhombohedric habitus. In many cases they are more flattened. The 

 power of crystallisating from the said solvent is extraordinarily 

 great. 



The symmetry is tncllno-pinacoidal; the axial elements are: 



r?:/;:c = 0,8443:l : 1,3600 



.4 = 101° 51'. a = 108° 24'. 



j5 = 116 51V;. /3 = 120'' 7'. 



C= 80°45V;. r= 73^ 8'. 



Forms observed are c = \ 001 1 , predo- 

 minating; rt = |100| and 6 = |010|, about 

 equally much developed; ???.^ jllOj, narrow; 

 /•' = {101 1 small and narrow, sometimes a 

 little broader; u^\lll\, small and much 

 less conspicuous. 



The crystals are represented in lig. 1; the 

 Fig. 1. measured and calculated angles are annexed: 



* 



n, 



m 



a 

 c 

 a 

 h 

 m 



Measured : 

 : b = (100) : (010) = 99^47/ 

 ; c = (100): (001) = 63 87, 

 c = (010) : (001) = 78 9 

 h = (110) : (010) = 58 197, 

 r'=(001):(T01) = 78 59 

 m = (100): (110) = 40 55 

 m = (001): (110) = 58 227, 

 r' = (100) : (101) = 37 55 

 r' = (010) : (lOl) = 71 35 

 r' = (110) : (101) = 61 53 



Calculated 



The crystals cleave quite parallel |100| and |010| 



1; Receuil d. Trav. Ghim. d. Pays-Bas, T. XIU. 99. 



