High-pressure bulk synthesis of crystalline C6N9H3•HCl:: A novel C3N4 graphitic derivative

A novel carbon nitride compound, structurally related to the proposed graphitic phase Of C3N4, has been synthesized in a bulk well-crystallized form. The new material. with stoichiometry C6N9H4Cl, was prepared through a solid-state reaction of 2,4,6-triamino-1,3,5-triazine with 2,4,6-trichloro-1,3,5-triazine at 1.0-1.5 GPa and 500-550 degreesC and also through a self-reaction of 2-amino-4,6-dichloro-1,3,5-triazine at similar conditions. X-ray and electron diffraction measurements on the yellowish compound indicate a hexagonal space group (P6(3)/m) with cell parameters of a = 8.4379(10) Angstrom and c = 6.4296(2) Angstrom. This new compound possesses a two-dimensional C6N9H3, framework that is structurally related to the hypothetical P6m2 graphitic phase of C3N4, but with an ordered arrangement Of C3N3 Voids. The large voids in the graphene sheets are occupied by chloride ions with an equivalent number of nitrogen atoms on the framework protonated for charge balance. The composition of the sample was determined by bulk chemical analysis and confirmed by electron energy loss (EELS) spectroscopy. The chemical and structural model is consistent with bulk density measurements and with the infrared and C-13 NMR spectra. This work represents the first bulk synthesis of a well-characterized and highly crystalline material containing a continuous network of alternating carbon and nitrogen atoms.