X-ray diffraction analysis of crystalline (buckminsterfullerene) shows that the crystal structure at — Solid State Chemistry Question

Question

X-ray diffraction analysis of crystalline $\text{C}_{60}$ (buckminsterfullerene) shows that the crystal structure at 300 K can be regarded as FCC with a one-molecule basis and unit cell edge length of $\sqrt{2} \text{ nm}$; the molecules are orientationally disordered due to rotation. The centre-to-centre distance (in nm) between nearest neighbour $\text{C}_{60}$ molecules in the solid at 300 K is