In a metal oxide,$O^{2-}$ ions are arranged in $hcp$ lattice while metal ions occupy $2/3$ of the octahedral voids. The simplest formula of the oxide is:

$A$ solid is made of two elements $X$ and $Y$. Atoms of $X$ are in $FCC$ arrangement and $Y$ atoms occupy all tetrahedral sites. What is the possible formula of the compound?

In a $A_x B_y$ crystal structure,$A^{+y}$ ions occupy all the tetrahedral voids and $B^{-x}$ ions form a $BCC$ unit cell. What is the formula of the compound?

$A$ metal $M$ forms a hexagonal close-packed structure. The total number of voids in $0.02 \ mol$ of it is $......... \times 10^{21}$ (Nearest integer) (Given $N_{A} = 6.02 \times 10^{23}$)

The correct option for the number of tetrahedral and octahedral voids in a hexagonal primitive unit cell is:

$A$ compound forms a hexagonal close-packed $(HCP)$ structure. What is the total number of voids in $0.5 \ mol$ of it? How many of these are tetrahedral voids?