Distinguish between : (i)Hexagonal and monoclinic unit cells. (ii)Face-centred and end-centred unit cells.

Distinguish between : (i)Hexagonal and monoclinic unit cells. (ii)Fac

1.	Distinguish between : (i)Hexagonal and monoclinic unit cells. (ii)Face-centred and end-centred unit cells.
Answer» Solution :(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.