A new three-dimensional structural model for the CuCl2 graphite intercalation compound

The in-plane structure of stage-1 to stage-3 CuCl2 graphite intercalation c ompounds (GIC) was investigated using X-ray and electron diffraction. A new 3D structural model of these CuCl2-GIC was defined based on a monoclinic, face-centred pseudo-orthorhombic unit cell and the X-ray and electron diffr action patterns were computed using this model. The modulations of the (00l ) intensities were well reproduced. The asymmetric shape of the CuCl2-GIC ( hk0) reflections may be explained by including additional (hkl) lines into the calculations. This is attributed to the preferred orientation of the do main islands in the GIG. The exact atom positions remain unknown, because d efects present in the noncommensurate GIC structure result in broad and asy mmetric diffraction peaks. The internal structure of the CuCl2 layers in th e GIC proved to be nearly the same as in the free compound. (C) 1999 Elsevi er Science Ltd. All rights reserved.