Heterogeneity of structure and motion in coals as revealed by 13C CP/MAS NMR

Carbon-13 CP/MAS NMR study of French coals and their maceral concentrates are described and discussed in terms of their structural and dynamic heterogeneity. Coals of different rank demonstrated significant structural differences evident in carbon-13 CP/MAS spectra. An important increase of structural homogeneity in coal with increase of the aromaticity factor has been noted. A comparison of maceral concentrates over a range of ranks permits the determination of structural differences within an individual maceral group