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

$A$ 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:

What is the minimum number of spheres required to develop a tetrahedral void?

The number of tetrahedral voids present in $0.5 \ mole$ of $hcp$ crystal structure is:

$A$ compound is formed by two elements $A$ and $B$. Atoms of the element $B$ (as anion) make $ccp$ lattice and those of element $A$ (as cation) occupy all tetrahedral voids. The formula of the compound is

In a compound made of atoms $A$ and $B$,atoms $A$ form an $fcc$ lattice,while atoms $B$ occupy $25\%$ of the tetrahedral voids and $50\%$ of the octahedral voids. If the crystal is cut such that all face-centered atoms along one axis are removed,the molecular formula of the resulting solid will be ...........