Single-crystal and synchrotron X-ray powder diffraction study of the one-dimensional orthorhombic polymer phase of C60

The 1D-orthorhombic polymer phase of C60 was originally mentioned in 1995. The present work provides the first direct experimental quantitative evidences of the 1D-polymer chains, clearly seen by single-crystal diffraction. Geometrical details of the [2+2]-cycloaddition rings are compared with those of C60 dimers and 2D-polymers. Another key structural parameter is the angle of rotation Ψ of the 1D chains about the polymerization axis. Single-crystal diffraction yields Ψ ≈ 78°, whereas accurate synchrotron powder diffraction independently produces a similar Ψ ≈ 73°. These values are in qualitative agreement with a former theoretical prediction (Ψ ≈ 61°).