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

The tetrahedral voids formed by $ccp$ arrangement of $Cl^{-}$ ions in rock salt structure are

What is the coordination number of $Ag^+$ in a $AgCl$ crystal lattice?

The radius of the largest sphere which fits properly at the centre of the edge of a body-centered cubic $(BCC)$ unit cell is (Edge length is represented by $a$) (in $a$)

$A$ compound is formed by elements $A$ and $B$. Element $A$ occupies the corners of the cube,and element $B$ occupies the face centers. What is the formula of the compound?

$A$ solid has a structure in which $W$ atoms are located at the corners of a cubic lattice, oxygen atoms at the edge centres, and $Na$ atoms at the body centre. The formula of the compound is: