Voids

The distance between an octahedral and a tetrahedral void in $\mathrm{pm}$ in FCC lattice would be: 

(Consider edge length is $7 \mathrm{pm}$)

Right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell are:

In a compound, atoms of element $\mathrm{Y}$ form cubic close packing lattice and those of element $\mathrm{X}$ occupy$\frac{2}{3} \mathrm{times}$  of tetrahedral voids. The formula of the compound will be

Octahedral voids are formed when the triangular voids in second layer exactly overlap with similar voids in the first layer.

A unit cell of ${\mathrm{B}\mathrm{a}\mathrm{C}\mathrm{l}}_2$ (fluorite structure) is made up of eight ${\mathrm{B}\mathrm{a}}^{2+}$ ions and four ${\mathrm{C}\mathrm{l}}^{-}$ ions.

The total number of tetrahedral voids in the face centred unit cell is

In a carbon allotrope having $\mathrm{FCC}$ lattice, two atoms are at $\left(0, 0, 0\right)$ and $\left(\frac{\mathrm{a}}{8}, \frac{\mathrm{a}}{8}, \frac{\mathrm{a}}{8}\right)$ coordinates. What is the ratio of $\mathrm{C}-\mathrm{C}$ bond length distance to the edge length of the unit cell?

In ${\mathrm{CaF}}_2$ crystal, ${\mathrm{Ca}}^{2+}$ions are present in fcc arrangement, calculate the number of ${\mathrm{F}}^{-}$ ions in the unit cell.

 In a compound, oxide ions are arranged in cubic close packing arrangement. Cations $\mathrm{A}$ occupy $1/6$ of the tetrahedral voids and cations $\mathrm{B}$ occupy $1/3$ of the octahedral voids. The formula of the compound is
 

For the structure given below the site marked as S is a :-

In a crystalline solid $\mathrm{x}$ atoms occupy hcp and $\frac{1}{4}$th of tetrahedral voids are occupied by $\mathrm{y}$ atoms. Then empirical formula of crystalline solid is:

The number of tetrahedral voids per unit cell in the $\mathrm{NaCl}$ crystal is

An ionic compound is expected to have a tetrahedral structure if ${\mathrm{r}}_{+}/{\mathrm{r}}_{-}$ lies in the range of

The total number of tetrahedral voids in the face-centred unit cell is _____.

Ferric oxide crystallizes in a hexagonal close packing array of oxide ions with two out of every three octahedral holes occupied by ferric ions. Derive the formula of the ferric oxide. 

If the radius of the octahedral void is $\mathrm{r}$ and the radius of the atoms in the close packing is $\mathrm{R}$, derive the relationship between $\mathrm{r} \mathrm{and} \mathrm{R}$. 

How will you distinguish between the following pairs of terms:

Tetrahedral void and octahedral void.

The number of tetrahedral sites per sphere in ccp structure is,

The number of octahedral sites per sphere in fcc structure is