Question

:
Find out the 1st and 2nd coordination number for an atom located at the comer in a simple cub
unit cell.​

Answer 1

Answer:

what are the conditions you haven't mentioned it

Answer 2

$\huge\boxed{\sf\color{red}{Ouestion :-}}$

Find out the 1st and 2nd coordination number for an atom located at the comer in a simple cub

unit cell.

$\huge\boxed{\sf\color{blue}{Answer :-}}$

Let the desired atoms is A

(i)1st C.N. 1st nearest neighbours are at a distance a (edge length ) from point A.So, 1st C.N.=6

(ii)2nd C.N. 2nd nearest neighbours are at a distance a √ 2 a2 from point A, as shown . For one plane (let X-Y) 2 n d 2nd nearest neighbrous =4 For three planes (XY,YZ and ZX), 2nd C.N. =12

(iii)3rd C.N. : 3rd nearest neighbours are at a distance a √ 3 a3 from point A , i.e., at the other end of body diagonals (as shown ) . A is contributed in eight cubes . So, 3rd C.N.=8