How many nearest neighbours are there for $Si$ and $O$ atoms in quartz crystals?

$NaCl$ is a $FCC$ lattice where $Na^{+}$ ions are at corner and face centre positions. Chloride ions are at edge centres and body centre positions. How many $NaCl$ formula units will be in a unit cell?

The coordination number of $Ba^{2+}$ ion in Barium fluoride $(BaF_2)$ is $8$. What must be the coordination number of fluoride ion $(F^{-})$?

The number of atoms in body-centred and face-centred cubic unit cells are,respectively:

$A$ compound made of elements $A$ and $B$ forms an $fcc$ structure. Atoms of $A$ are at the corners and atoms of $B$ are present at the centres of the faces of the cube. What is the formula of the compound?

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