Question

The packing efficiency of the face centered cubic $(fcc),$ body centered cubic $(bcc)$ and simple/primitive cubic $(pc)$ lattices follows the order

• A. fcc > bcc > pc
• B. bcc > fcc > pc
• C. pc > bcc > fcc
• D. bcc > pc > fcc

Answer 1

Answer: (A)

The packing efficiency of cubic lattice is given by formula Volume occupied by
$PE=\frac{\text{ spheres in lattice }\times 100}{\text{ Total volume of the unit cell }}$
Packing efficiency of fee $=74\%$
Packing efficiency of bcc $=68\%$
Packing efficiency of pc $=52.4\%4$
Thus, packing efficiency follow the order
$fcc>bcc>pc$