E.p.r. study of molecular phases in coal

E.p.r. spectra from coals of various carbon content are reported. The e.p.r. signal from coals in a vacuum consists of two lines with different widths. The results are interpreted using the Larsen-Kovac structural model (Am. Chem. Soc. Div. Fuel Chem. Preprints 1977, 22, 181). The paramagnetic centres, disposed in the macromolecular phase, give a narrow line whereas the spins of the molecular phase are responsible for the broad line. These results provide a good interpretation of the changes in e.p.r. signal-shape under the influence of various organic solvents observed by Yokokawa (Fuel 1968, 47, 273; Fuel 1969, 48, 29).