The packing efficiency of simple cubic (sc.) body centred cubic (bcc) and cubic close packing (ccp) lattices follow the order

Options

A. bcc lt ccp lt sc
B. ccp lt bcc lt sc
C. sc lt ccp lt bcc
D. sc lt bcc lt ccp

Answer

d

Explanation

packing efficiency for simple cubic
`((4 pi r^(2))/(3))/(a^(3)) xx 100 = ((4 pi r^(3))/(3))/(8 pi r^(3)) xx 100 = 52.4%`
For body contred `= (2 xx (4)/(3) pi r^(3))/(64 r^(3))/(3 sqrt(3)) xx 100 = 68%`
For cubic closed packing `= (4 xx 4 pi r^(2) // 3)/(32 r^(2) // sqrt(2)) xx 100 = 74%`
Hence , `sc lt bc c lt c cp`