Synthesis and characterization of the bulk crystalline carbon–nitride phase synthesised by high-pressure technique

The crystalline carbon–nitride phase was synthesised by high-pressure technique from amorphous powder precursor containing carbon, nitrogen and hydrogen. The synthesised material was analysed by X-ray diffraction, IR technique, and Auger electron spectroscopy. Almost all the observable peaks (except of the two peaks) can be identified on the basis of the hexagonal unit cell with the following parameters: a=0.665 nm, c=0.482 nm. IR spectrum has a sharp absorption at 1375 cm−1 and a broad absorption at 1640 cm−1. These two peaks can be assigned as the CN and CN stretching modes, respectively. The Auger spectra are similar to the ones observed in diamond. The model of a crystalline carbon–nitride with hexagonal β-C4N structure is proposed. In this model a part of the nitrogen atoms is replaced by the carbon atoms that will occupy adjacent sites and form CC bonded pairs.