Hongshiwan (HSW) coal from Ningdong China was characterized to determine key microstructural parameters of materials

such as elements

valence and chemical bonding

with proximate and ultimate analyses

solid state 13C nuclear magnetic resonance (13C NMR)

X ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The results revealed that main structure of HSW coal was 75.96%(mass) aromatic skeleton and 0.315 ratio of aromatic bridge carbon to aromatic peripheral carbon

indicating more naphthalene than benzene and anthracene in coal. Oxygen predominantly presented in the form of ether (C-O)

carbonyl (C=O) and carboxyl (-COO)

which C-O was accounted for 53.57%. Nitrogen presented in the form of pyridine and pyrrole. Tri-and tetra-substituents were mainly located on benzene ring at 47.77% and 32.97%

respectively. Methyl (-CH3) group was predominant in cyclic and aliphatic hydrocarbons. Thus

coal molecular formula was defined as C221H148O28N2 with molecular weight of 3142.32. Based on these results

macromolecular 2D and 3D model of HSW coal was built with computer-aided modelling. The model was optimized and further verified by FT-IR and 13C NMR spectra simulation by quantum chemical calculations. Therefore

molecular microstructures of HSW coal have been depicted from both experimental and quantum chemical approaches.