This research has utilized matrix isolation FTIR and EPR for characterization of volatilized coal products. Both slow and rapid heating studies were carried out on four coals, Illinois No. 6, Pittsburgh bituminous, Rawhide sub-bituminous and Texas lignite. Pyrolysis products have been correlated to coal type and initial coal composition. Evolution of both a low and high temperature form of tar has been observed. Methylation of the hydroxyl structure in coal enhances the evolution of the low temperature form. Only the high temperature tar is found to contain free radical character. Significant temperature dependent evolution of CO, CO/sub 2/, H/sub 2/O, H/sub 2/S, CS/sub 2/, CS, HCN, C/sub 2/H/sub 4/, and CH/sub 4/ is observed and interpreted in terms of reaction mechanisms which occur during pyrolysis. Reaction of kaolinite with char is observed at high temperatures (1150 to 1500/sup 0/C) to form volatile species SiO, Al/sub 2/O, and aluminum atoms. Significant evolution of the methyl free radical was observed for the first time. This observation strongly implies that direct bond dissociation of existing methyl groups in coal is a major reaction mechanism leading to methane formation. Infrared spectra of the matrix isolated tar has shown that only the phenolic hydroxyl group remains in the tar after vaporization. Studies of methylation of the hydroxyl groups present in coal with a deuterated methyl group have allowed the identification of three distinct hydroxyl sites. They have been identified as carboxyl, phenolic and alcoholic in character. EPR spectra of the matrix isolated tars have shown significantly increased detail as compared to the respective coals. The spectra indicate that the free radical sites in the tars are delocalized over aromatic rings. Four different types of free radical species are observed and are tentatively associated with aromatic rings which contain no heterocycles as well as those with sulfur, nitrogen, and oxygen. 12 refs., 47 figs., 17 tabs.