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Peat char samples produced by heat treatments under an inert atmosphere of nitrogen were characterized through ¹³C solid-state NMR, allowing the achievement of a detailed picture of the mechanism of carbonization. The treatments were realized at temperatures between 200 and 1000 °C, with a controlled heating rate and residence time. NMR spectra were obtained in a home-built spectrometer operating at a field of 2.0 T with the use of high-resolution techniques. The results showed the steps followed during the carbonization process. Initially we observed a degradation of the natural material, with preferential loss of carbohydrates and carboxylic groups. From a heat-treatment temperature of about 500 °C upward, the spectra were nearly constituted of only one resonance line with a chemical shift of about 130 ppm (from TMS), typical of aromatic structures. For the most severely treated samples, a decrease in …