STRUCTURE OF A NOVEL FORM OF CARBON - DEHYDROPOLYCONDENSED ADAMANTANE

The paper presents synchrotron X-ray diffraction and complementary tra nsmission TR spectroscopy data on a series of products of adamantane i n an attempt to elucidate the detailed nature of their structure. Alth ough qualitative similarities between this work and earlier studies ha ve been identified, the X-ray diffraction measurements, when coupled w ith IR absorption analysis, argue for a very different interpretation of the structural changes associated with the chemical processes invol ved in generating this suite of materials. It is clear that 1,3,5,7-te trabromoadamantane has indeed been formed from the adamantane precurso r, but that there are some Br sites that are occupied by carbon atoms. 'Polymerisation' of these units into an amorphous network with no res idual long-range ordering may then be induced through chemical process es; the C-10 carbon units are broken up to form an amorphous network ( or 'patchwork') of unit fragments. The corroborating presence of short hydrocarbon chains is also revealed. Once the material is heat treate d it begins to revert to a graphitic structure, with the hydrocarbon c hains being eliminated.