In which compound is $8:8$ coordination found?

In the fluorite structure,the coordination number of the $Ca^{2+}$ ion is.....

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

The number of nearest neighbours in a $BCC$ unit cell is

In a face-centered cubic lattice of $X$ and $Y$ atoms,$X$ atoms are present at the corners while $Y$ atoms are at the face centers. If two atoms of $X$ are missing from the corners,what is the formula of the compound?

The coordination number of a hexagonal close-packed $(hcp)$ crystal structure is......