# in a compound, XY2O4, oxide ions are arranged in ccp. cations X are present in the octahedral voids and y is equally distributed between octahedral and tetrahedral voids. what is the fraction of octahedral voids occupied?

31 Points
12 years ago

Hi Pooja,

No of atoms in ccp is 4 and in this ques these are oxide ions. So there will be 8 tetrahedral voids and 4 octahedral voids per unit cell. In a unit cell 1 x and 1 Y occupy octahedral voids. so 2 out of 4 octa. voids are occupied : implies 50% or 1/2 is the fraction of octahedral voids occupied.

Hope that helps.

Manav
11 Points
6 years ago
No of octahedral voids present in a CCP lattice are 4 and as y is equally distributed among octahedral and tetra voids and we require 2 atoms of y so it occupies 1 octahedral and 1 tetra and also X are present in octahedral void and we require only one X atom so only one octahedral is required so No of octahedral voids used are 2And total no of octahedral voids are 4So fraction of octahedral voids used are 2/4 =0.5
Rishi Sharma