The number of tetrahedral voids in the unit cell of a face-centered cubic $(fcc)$ lattice of similar atoms is:

If the anion $(A)$ forms a hexagonal closest packing and the cation $(C)$ occupies only $2/3$ of the octahedral voids in it,then the general formula of the compound is :-

Element '$B$' forms $ccp$ structure and '$A$' occupies half of the octahedral voids,while oxygen atoms occupy all the tetrahedral voids. The structure of bimetallic oxide is

$A$ metal oxide crystallises in a hexagonal close-packed $(HCP)$ array of oxide ions with two out of every three octahedral holes occupied by metal ions. The formula of the metal oxide is:

$A$ crystalline solid $XY_3$ has a $ccp$ arrangement for its element $Y$. $X$ occupies:

If the anions $(A)$ form hexagonal closest packing and cations $(C)$ occupy only $2/3$ of the octahedral voids in it,then the general formula of the compound would be