In an alloy atom X occupies the corner positions and atom Y occupies the face centre positions of fcc lattice.If one of the face centre atom is missing then formula of the compound is

In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centred positions. If one atom of B is missin from one of the face centred points,, the formula of the compound is :

A solid compound contains X,Y and Z atoms in a cubic lattice with X atoms occupying the corners ,Yatoms in the body centred position and Z atoms at the centre of the faces of the unit cell .What is the empirical formula of the compound?