Synthesis of Ultra-Incompressible and Recoverable Carbon Nitrides Featuring CN<sub>4</sub> Tetrahedra.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37822038.
- Also identified by DOI 10.1002/adma.202308030 and PMC identifier 11475261.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Carbon nitrides featuring three-dimensional frameworks of CN<sub>4</sub> tetrahedra are one of the great aspirations of materials science, expected to have a hardness greater than or comparable to diamond. After more than three decades of efforts to synthesize them, no unambiguous evidence of their existence has been delivered. Here, the high-pressure high-temperature synthesis of three carbon-nitrogen compounds, tI14-C<sub>3</sub> N<sub>4</sub> , hP126-C<sub>3</sub> N<sub>4</sub> , and tI24-CN<sub>2</sub> , in laser-heated diamond anvil cells, is reported. Their structures are solved and refined using synchrotron single-crystal X-ray diffraction. Physical properties investigations show that these strongly covalently bonded materials, ultra-incompressible and superhard, also possess high energy density, piezoelectric, and photoluminescence properties. The novel carbon nitrides are unique among high-pressure materials, as being produced above 100 GPa they are recoverable in air at ambient conditions.