CBSE Class 12-science Answered

Show that edge centered cube and body centered cube has 2 atoms.

Ans- The body-centered cubic unit cell has atoms at each of the eight corners of a cube  plus one atom in the center of the cube. Corners will always be 1/8 and 1 in the center.

8 corners x 1/8 = 1

Body center = 1x1 therefore total 2 atoms per unit cell.

The edge centered cubic structure has atoms located at each of the corners and the centers of two opposite cubic face. 1/8  from corners atoms and 2 halves of the face atoms.

Corner -------- 8x 1/8 = 1

Face-----------2x ½ = 1 therefore total 2 atoms per unit cell.