HMTTEF.C60-A 2-D close-packed layered compound of C60

The analysis of high resolution synchrotron X-ray powder diffraction data of HMTTEF.C60, (HMTTEF = hexamethylenetetratellurafulvalene) gave a triclinic unit cell with a 9.9297 Å, b = 9.9359 Å, c = 13.1472 Å, α = 106.966 °, β = 95.887 ° and γ = 118.252 ° in the space group P1̄. Steric considerations suggest that there is a nearly close-packed layer of C60 molecules in the ab plane, and HMTTEF molecules are sandwiched between layers of C60. The compound is insulating and weakly paramagnetic and the charge-transfer is small.