The 1D-orthorhombic polymer phase of C-60 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 C-60 dimers and 2D-polymers. Another key structural parameter is the angle of rotation Psi of the 1D chains about the polymerization axis. Single-crystal diffraction yields Psi approximate to 78 degrees, whereas accurate synchrotron powder diffraction independently produces a similar Psi approximate to 73 degrees. These values are in qualitative agreement with a former theoretical prediction (Psi approximate to 61 degrees). (C) 2008 Elsevier B. V. All rights reserved.