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

Explanation

(i) For hexongonal unit cell , ` a = b ne c, alpha = beta = 90^(@) , gamma= 120^(@)`
for monoclinic unit , ` a ne b ne c, alpha = gamma = 90^(@) , beta ne 90^(@)` ,
(ii) A face -centred unit cell has one constituent paticel 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.