How many lattice points are there in one | Class 12 Chemistry Chapter The Solid State, The Solid State NCERT Solutions

Question:

How many lattice points are there in one unit cell of each of the following lattice?

(i) Face-centred cubic

(ii) Face-centred tetragonal

(iii) Body-centred

Answer:

(i) No. of corner atoms per unit cell = 8 corner atoms x 1/8 atom per unit cell

                 = 8 x 1/8 = 1 atom

    No. of face centred atoms per unit cell = 6 face centred atoms x 1/2 atom per unit cell

                 = 6 x 1/2 = 3 atoms

    :. Total no. of atoms or labtice points = 1+3= 4 atoms.
 

(ii) Face centered tetragonal

             8 lattice points at corners and 6 lattice points at face centres

         :. 8 x 1/8 + 6 x 1/2 = 4

 

(iii) In bcl unit cell, no. of corner atoms per unit cell 

            = 8 x 1/8 per corner atom

            = 1 atom

      No. of atoms at body centre = 1 atom

     :. Total no. of atoms (lattice points) = 1 + 1 = 2


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Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 8: How many lattice points are there in one unit cell of each of the following lattice? (i) Face-cen....