188 Wyckoff — Crystal Structure of Silver Oxide. 



not only the simple grouping (a) but likewise all of the 

 more complicated groupings possess holohedral sym- 

 metry, it is evident that, assuming as we have that the two 

 silver atoms of Ag 2 are equivalent, this explanation is 

 untenable. If a real enantiomorphism exists in the case 

 of cuprous oxide, it must be traced to some other cause 

 than symmetry of the arrangement of the atoms. 



Summary. — Employing the method of powders, it is 

 shown that silver oxide has the same structure as that 

 assigned to cuprous oxide. The length of the side of the 

 unit cube is determined to 4.76 8 A. U. 



Geophysical Laboratory, 



Carnegie Institution of Washington. 



