K 4 C 60 -like crystals (space group I4/mmm, No. 139) were formed using 350 nm (+) PS and 160 nm (-) PS particles (β = 0.46) at a 1:4 number ratio, as well as 200 nm (+) PS and 400 nm (-) PS particles (β = 0.50) at the same number ratio. The larger particles are positioned at the body-centered cubic (bcc) lattice sites. The small particles filled all the tetrahedral interstitial sites of the (001) plane and only half of the (100) and (010) planes.