What is the coordination number of a cation present in a tetrahedral void?

The $FCC$ unit cell of a compound contains ions of $A$ at the corners and ions of $B$ at the centre of each face. What is the formula of the compound?

In a face-centered cubic lattice,a unit cell face is shared equally by how many unit cells?

$A$ solid compound contains atoms $X, Y,$ and $Z$. In its unit cell,atoms $X$ are at the corners,atoms $Y$ are at the body center,and atoms $Z$ are at the face centers. The formula of the compound is:

$(i)$ What is meant by the term 'coordination number'?
$(ii)$ What is the coordination number of atoms:
$(a)$ in a cubic close-packed structure?
$(b)$ in a body-centred cubic structure?

In the rock salt structure,the $ccp$ arrangement of $Cl^{-}$ ions creates tetrahedral voids,which are....