Fluorine intercalation in carbon alloy CxN

Fluorine intercalation in nitrogen-substituted carbon CxN has been investigated at a temperature ranging from room temperature to 300 degrees C. C16N and C14N yielded the fluorinated products with low C/F ratios, C3F under fluorine pressures of 1.0 x 10(5) and 0.5 x 10(5) Pa at room temperature. The intercalated fluorine decreased with decreasing nitrogen content in the host CxN, in particular at 0.25 x 10(5) Pa. X-ray powder diffraction data revealed that fluorine-intercalated CxN samples consisted of mixtures of several stages or mixtures with unreacted phase, having lower stages than those prepared from carbon. XPS and IR absorption spectra indicated the formation of semi-ionic C-F bonds. It was found that fluorine intercalation was much easier in CxN than in carbon between 50 degrees C and 200 degrees C. XPS and IR absorption spectra showed that C-F bonding varied from semi-ionic to covalent with increasing fluorination temperature from 50 degrees C to 300 degrees C. IR absorption spectrum suggested the formation of NF2 groups at 300"C. (C) 1999 Elsevier Science S.A. All rights reserved.