In zinc blende structure anions are arranged in ccp and cations are present in the tetrachedral voids and only half the tetrahedral voids are occupied,
for this type of structure , radius ratio r/r should be in the range
A. 0.225 – 0.414
B. 0.155 – 0.225
C. 0.414 – 0. 732
D. 0.732-1

In zinc blende structure anions are arranged in ccp and cations are present in the tetrachedral voids and only half the tetrahedral voids are occupied,
the coordination numbers of cation and anion are respectively
A. 4 and 8
B. 4 and 4
C. 8 and 4
D. 8 and 6