High-Pressure Synthesis of Crystalline Double-Layer Carbon Nitride Networks Stabilized in Bi₇C₁₀N₁₈(N_{3(1- x )}O_{3 x})

Application of high-pressure conditions in chemical synthesis has proven to access a wide range of novel nitrogen-rich compounds and to overcome the stability of the dinitrogen molecule. In the present work, we report the high-pressure high-temperature (HPHT) synthesis of Bi₇C₁₀N₁₈(N_{3(1- x )}O_{3 x}), which features double-layers of poly-N-(1,3,5-triazin-2-yl)-guanidine [C₄N₆ ^{x -}]_n and non-polymerized guanidinate anions CN₃ ^5-. The structure model was determined by means of synchrotron single-crystal X-ray diffraction and is fully corroborated by theoretical calculations. The poly-N-(1,3,5-triazin-2-yl)-guanidine illustrates an example of a 2D polymerized anionic C─N network and represents the first intermediate between highly charged CN₃ ^5- anions and fully condensed graphitic carbon nitride networks achieved by HPHT conditions. This opens a pathway to a widely varied family of hydrogen-free nitridocarbonates, which has the potential to develop into an alternative synthesis route to classical polycondensation reactions.