Question

Number of atoms per unit cell if atoms are present at the corner of unit cell and 2 atoms at each body

Answer 1

Answer is 9 Nine.

First imagine a cube.

There are 8 corners in corner.

1 atom in one corner.

So 8 unit cells surround this corner (ie- tis one cell lies in eight unit cells)

So This unit cell has 1/8 cells at corner.

There are eight corners and same in each case.

So number of cells in this unit cell by corner atom is (1/8)×8= 1

Imagine body diagonals of a cube.

If you are perfect in imagination there are 4 body diagonals each having 2 atoms(given in question)

Now atoms present don't share with any other unit cells since these are inside unit cell.

Total atoms by body diagonals are 4×2= 8

Total atoms by unit cell is 8( body diagonals) +1( corners)

=9

Practically

In a ccp body diagonals have 2 tetrahedral voids each.

Since a ccp is not considered but a hypothetical cube is taken and arranged in such way. It may not form a perfect cube in complete stacking.

I think this would look like a simple cube with an extra atoms at corners from central locus. So I think this cannot exist..

I told I am just a beginner if I was wrong please let me know. These are just my assumptions.

 

Answer 2

Explanation:

it can help.............................