Density, d=530kg/m3=0.530g/cm3
(∵1kg/m3=10−3g/cm3)
Molar atomic mass, M=6.94g/mol
For bcc unit cell, the number of atoms per unit cell, Z=2
Density, d=ZMa3NA
0.530=2×6.94a3×6.023×1023
a3=4.34×10−23
⇒a=3.52×10−8cm
The edge length, a=3.52×10−8cm=352×10−12m=352pm
(∵1m=100cm and 1pm=10−12m)