The maximum radius of a sphere that can be fitted in the octahedral hole of a cubical closed packing of spheres of radius $r$ is $..............$ $r$.

In a face-centered cubic $(FCC)$ close-packed structure,the third layer covers the ..... voids created between the first and second layers.

The number of octahedral and tetrahedral holes respectively present in a hexagonal close packed $(hcp)$ crystal of $X$ atoms are

Hexagonal close packed arrangement of ions is described as

In a close-packed arrangement,$A$ type of atoms are at corners,$B$ type of atoms are at face centers,$C$ type of atoms are at tetrahedral voids,and $D$ type of atoms are at octahedral voids. If all the atoms along any one body diagonal are removed,what will be the formula of the compound?

The compound forming $ccp$ structure contains $9.6 \times 10^{23}$ atoms. Find the number of tetrahedral voids formed in it.