How many atoms can be assigned to its unit cell if an element forms (a) Simple cubic unit cell? (b) Body centred cubic unit cell? (c) Face centred cubic unit cell?
(a) 8(corners atoms) × 1/8 (atoms per unit cell ) = 1 (b) 8 (corners atoms) × 1/8 + 1 ( body centre atom ) × 1 = 1+1 = 2 (c) 8(corners atoms) × 1/8+6(face centre atoms) 1/2= 1+3= 4
