The molecular structure of coals and humic acids is studied by destroying the individual links in the molecules, avoiding their decomposition and taking the characteristics of the products into consideration. The process is carried out in steps, or by gradually increasing the rigidity of the conditions, by a combination of reducing and oxidizing methods. Reduction destruction of coals and humic acids can be accomplished by hydrogenation at various temperatures using a known procedure. Yield, structural-group composition, and the characteristics of the hydrogenators (including insoluble residues and gaseous products) in combination with the chemical characteristics of the original substance, provide the means for arriving at the heterocycles, the condensed aromatic and naphthein rings in the link. A tentative model of their structure can be constructed on the basis of the results obtained.