1.10 Calculate the efficiency of packing in case of a metal crystal for
(iii) face-centred cubic (with the assumptions that atoms are touching each other).
In fcc, we know that we have a total of 4 efficient atoms present.
Also, radius and edge length of the sphere can be related by the following relation :
The above relation can be found out by equating diagonal of 1 face to 4r. (2r from the atom at face centre and r from each atom at a corner.)
Thus packing efficiency becomes:-