A given metal crystallises out with a cubic structure having edge length of 361 pm. If there are four metal atoms in one unit cell, what is the radius of one atom ?

Given, edge length = 361PmFour metal atoms in one unit celli.e. effective number of atoms in a unit cell (r) - 4 (given)∴It is a fcc structure.∴Face diagonal, 2a=4r⇒            r=2×3614=127 pm.