The number of octahedral void$(s)$ per atom present in a cubic close-packed structure is

Identify the types of voids represented by the structures $I$,$II$,and $III$ in the given image.

How many tetrahedral voids are present in $0.4 \ mol$ of a compound that forms an $hcp$ structure?

$A$ body-centred cubic $(BCC)$ lattice is made up of two different types of atoms $X$ and $Y$. Atom $X$ occupies the body centre and atoms $Y$ occupy the corner positions. One of the corners is left unoccupied per unit cell. The empirical formula of it is

In a structure of mixed oxide,oxide ions are in $CCP$. One-fifth of tetrahedral voids are occupied by divalent ion $(A^{2+})$ while half of the octahedral voids are occupied by trivalent ion $(B^{3+})$. The formula of the oxide is:

$A$ compound made up of elements $A$ and $B$ (with a general formula $A_x B_y$),where $B$ forms an $hcp$ lattice and $A$ occupies $2/3$ of the tetrahedral voids. The formula of the compound is