Suppose an ionic solid with a cubic unit cell contains a (cations) and z (anions). the a ions are in the body center position and at each corner, and the z ions are on each face. based on this structure the empirical formula of the compound would be az

The empirical formula of the compound would be

Explanation:

The A ions are in the body center position and at each corner .

There are 8 faces of the cube and 1 corner is also shared by another 7 cubic unit.

Then number of A ion in a cubic unit =

The Z ions are on each face of the cubic unit :

There are 6 faces of the cube and 1 face is shared by another cubic unit.

Then number of Z ions in a cubic unit =

The structural formula of the cubic lattice is  =

Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.

The empirical formula of the compound would be

what is the question here. i think you messed up.