Distinguish between
a. Hexagonal and monoclinic unit cells
(b) Face-entred and end-centred unit cells

Explanation

For hexagonal unit cell, a =b `ne`c,`alpha=beta=90^@, gamma= 120^@`
For monoclinic unit cell, `a ne b ne c , alpha = gamma = 90^@, beta ne =90^@`
(ii) A face-centred unit cell has one constituent particle present at the centre of each face in addition to the particles present at the corners .
An end-face centred has one constituent particle each at the centre of any two opposite faces in addition to the particles present at the corners