Question

If AgI crystallize in zinc blende structure with $I^{-}$ ions at lattice points, what fraction of tetrahedral voids is occupied by $A{g}^{+}$ ions?

• A. $25\%$
• B. $50\%$
• C. $100\%$
• D. $75\%$

Answer 1

The correct option is B $50\%$

For each $I^{-}$ ion, there are 2 tetrahedral voids since number of $A{g}^{+}$ ions is equal to $I^{-}$ ion thus, only $50\%$ tetrahedral voids are occupied by $A{g}^{+}$ ions.