Copper crystallizes in $f.c.c.$ with a unit cell length of $361 \ pm$. What is the radius of copper atom? (in $pm$)

In a solid $AB$,$A$ atoms are in $ccp$ arrangement and $B$ atoms occupy all the octahedral sites. If two atoms from the opposite faces are removed,then the resultant stoichiometry of the compound is $A_{x} B_{y}$. The value of $x$ is ..... [nearest integer]

The $Ca^{2+}$ and $F^{-}$ ions are located in $CaF_2$ crystal,respectively,at face-centered cubic lattice points and in

The ratio of cationic radius to anionic radius in an ionic crystal is greater than $0.732$. Its coordination number is

What is the total number of atoms in a $BCC$ crystal lattice having $1.8 \times 10^{20}$ unit cells?

In an ${A^{+}}{B^{-}}$ ionic compound, the radii of ${A^{+}}$ and ${B^{-}}$ ions are $180 \ pm$ and $187 \ pm$ respectively. The crystal structure of this compound will be: