EPR characteristics of petrographically complex coal samples from durain and clarain

Electron paramagnetic resonance (EPR) spectroscopy was used to analyse properties of paramagnetic centres systems of the samples separated from two lithotypes of Polish coal (85.6 wt% C). The EPR spectra of the durain samples with a content of 2–22 vol.% exinite, 73–86 vol.% vitrinite and 5–17 vol.% inertinite, and the clarain samples with a content of 3–14 vol.% exinite, 65–90 vol.% vitrinite and 4–32 vol.% inertinite were compared. Three different groups of paramagnetic centres in each of the coal samples were found. The concentration of unpaired electrons and the parameters of the resonance absorption curves: linewidths and g-factor, were determined.