Potassium fluoride $(KF)$ has an $NaCl$ type structure. What is the distance between $K^{+}$ and $F^{-}$ ions if the unit cell edge length is $a \ cm$?

What is the coordination number in a calcium fluoride $(CaF_2)$ type structure?

$A$ compound of $A$ and $B$ crystallises in a cubic lattice in which $A$ atoms occupy the lattice points at the corners of the cube. The $B$ atoms occupy the centre of each face of the cube. The probable empirical formula of the compound is

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

The crystal structure of $AB$ is of $NaCl$ type. If the radius of the $A^+$ ion is $x \ pm$ and the radius of the $B^-$ ion is $y \ pm$, then the edge length of the unit cell will be ..........

The number of nearest neighbours and next nearest neighbours of an $Na^{+}$ ion in a crystal of $NaCl$ are respectively