DIFFRACTION STUDIES OF COAL STRUCTURE

This work is a review of some recent papers, and presents the results and interpretation of X-ray studies on coal structure. It was found that: the ratios of sp2 sp3 carbon atoms obtained from X-ray studies are in agreement with those of other studies; the sp3 atoms form layers of carbon rings; the sp2 atoms form layers of 4-20 rings, depending on the petrographic component and the rank of coal; and non-organized carbon can be neglected in diffraction studies. © 1990.