Question

The density of chromium metal is 7.29 g cm^-3. If the unit cell is cubic with edge length of 289 pm, determine the type of unit cell (simple, body centred or face-centred) (Atomic mass Cr = 52 a.m.u).

Answer 1

Given: Density (d) = 7.29 g cm^-3 , Edge length (a) = 289 pm = 289 \(\times\)10^–12 m = 289 \(\times\)10^-10 cm

Atomic mass = 52 a.m.u.

To find: Type of unit cell

\(\therefore\) Type of crystal lattice = bcc

Ans: Since the given unit cell contains 2 atoms, it has a body centred cubic (bcc) structure.