In a compound, oxide ions constitute cubic close packing. Cations A occupy 50% of tetrahedral holes while cations B occupy all the octahedral voids. The empirical formula of the compound is ?
Number of O2− ions per unit cell =18×8(corners)+12×6 (faces)=4
Number of A cations per unit cells =50100×8(tetrahedral voids)=4
Number of B cations per unit cell = 4 (octahedral voids).
Hence, the empirical formula =A4B4O4 or ABO