# distinguish between hexagonal and monoclinic unit cell face centred and end centred unit cell

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question : distinguish between hexagonal and monoclinic unit cell face centred and end centred unit cell ?

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here we gonna see the solution of distinguish between –

1. hexagonal and monoclinic unit cell
2. face centred and end centred unit cell

Points to remember to answer this question : differentiation between the hexagonal and monoclinic unit cell can be seen on the basis of axial distance , axial angles and on the basis of examples. so we will keep in mind to answer 1st portion of the question.

The second portion of this question can be answered on the basis of position of lattice point and also the numbers of atoms per unit cells because the given unit cells different in these unit cells.

Solution :

1. hexagonal unit cell :

axial distances hexagonal unit cell : a = b ≠ c

axial angles in hexagonal unit cells : α = β = 90°, γ = 120°

examples of hexagonal unit cells : graphite , ZnO , CdS , tourmaline, emerald, ruby, cinnabar etc.

possible variations in hexagonal unit cell : primitive

structure of hexagonal unit cells – 2. monoclinic unit cell key points :

axial distances hexagonal unit cell : a ≠ b ≠ c

axial angles in hexagonal unit cells : examples of monoclinic unit cell : sodium sulfate decahydrate (Na2SO4 · 10H2O) , monoclinic sulphur , borax, orthoclase, kaolin , azurite, and spodumene etc.

structure of monoclinic unit cell – possible variations in monoclinic unit cell – primitive and end centred .

## distinguish between face centred and end centred unit cell

1. face centred unit cell : In face centred unit cell the constituent particles which may be atoms , ions or molecules are present or found at the position at the corner and one is found at the center of the each face . in short we can say that –

position of lattice point : at corner and at the centre of each face of unit cell.

numbers of atoms per unit cells in face centred unit cell = 4

calculation as follows – 2. end centred unit cell : In end centred unit cell the constituent particles (atoms etc.) found at the corner and one at the centre of any two opposite faces (2 end faces) of the unit cell.

numbers of atoms per unit cells in end centred unit cell = 2

calculation as follows – 