The structural parameters of nine coal samples from a contact metamorphic zone were studied by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The FTIR spectra parameters composed of CH 2 /CH 3 , f a , H al /H ar , and (R/C) u indicate distinguishing features, including increase of aromaticity and the loss of aliphatic and oxygencontaining groups with thermally metamorphic evolution of coal. The XRD analysis shows that magmatic intrusion potentially caused rapid changes of structures in coal. With the decrease of distances from the intrusion rocks, the average lateral sizes (L a ), stacking heights (L c ), and interlayer spacing (d 002 ) of the crystallite structures of coal range from 22.90 to 37.70 Å, 12.90 to 23.30 Å, and 3.80 to 3.50 Å, respectively. Exponential correlations are observed between structural parameters (f a , d 002 , L a , L c , H al /H, (R/C) u , and A ar /A al ) and C/H of the coal, suggesting that the structures of coal are controlled by the degree of contact metamorphism.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.