In which of the following crystals are alternate tetrahedral voids occupied?

Platinum crystallizes in a face-centered cubic $(FCC)$ crystal with a unit cell edge length $a$. The distance between nearest neighbour atoms is

The structure of $ZnS$ is

Which of the following exhibits an $8:8$ coordination type packing?

The radius of the calcium ion is $94 \text{ pm}$ and the radius of the oxide ion is $146 \text{ pm}$. What is the possible crystal structure of calcium oxide?

What is the minimum limiting radius ratio for an octahedral arrangement?