High-Pressure Synthesis of Two Pb<sub>3</sub>(C<sub>3</sub>N<sub>6</sub>) Polymorphs Featuring Fully Deprotonated [C<sub>3</sub>N<sub>6</sub>]<sup>6–</sup> Melaminate Anions
Graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>), melamine, and their derivatives are of significant interest due to their diverse structural properties and potential applications in catalysis, energy storage, and materials science. In this study, two new compounds, both with the Pb<sub>3</sub>(C<sub>3</sub>N<sub>6</sub>) chemical formula, were synthesized at pressures of 40(2) to 48(2) GPa through a direct reaction between Pb, C and N<sub>2</sub>, or Pb and C<sub>6</sub>N<sub>4</sub>, in laser-heated diamond anvil cells. Their crystal structures were solved and refined using synchrotron single-crystal X-ray diffraction. The two Pb<sub>3</sub>(C<sub>3</sub>N<sub>6</sub>) polymorphs, namely <i>tP</i>48-Pb<sub>3</sub>(C<sub>3</sub>N<sub>6</sub>) and <i>hP</i>72-Pb<sub>3</sub>(C<sub>3</sub>N<sub>6</sub>), crystallize in the noncentrosymmetric space groups <i>P</i>4̅2<sub>1</sub><i>m</i> and <i>P</i>6<sub>1</sub>22, respectively. Both solids contain the previously unknown hydrogen-free [C<sub>3</sub>N<sub>6</sub>]<sup>6-</sup> melaminate anion and were experimentally found recoverable to ambient conditions. Density functional theory calculations provide further insights into the structural and electronic properties, and reveal that both compounds are direct narrow band gap semiconductors.
Authors
- J. Ball (ORCID: https://orcid.org/0000-0001-5830-8268)
- Dominique Laniel (ORCID: https://orcid.org/0000-0002-6889-9820)
- Umbertoluca Ranieri (ORCID: https://orcid.org/0000-0003-2026-6132)
- Christopher J. Lamb (ORCID: https://orcid.org/0000-0002-2443-0596)
- James Spender
- Bernhard Massani (ORCID: https://orcid.org/0000-0002-5817-1780)
- Angelika Dorothea Rosa (ORCID: https://orcid.org/0000-0002-2304-1943)
- Pierre‐Olivier Autran (ORCID: https://orcid.org/0000-0003-4600-6371)
- Ferenc Tasnádi (ORCID: https://orcid.org/0000-0001-6373-5109)
- S. R. Bolton
- Akun Liang (ORCID: https://orcid.org/0000-0002-0515-0484)
- Andrey Aslandukov (ORCID: https://orcid.org/0000-0003-0988-6066)
- Bihan Wang (ORCID: https://orcid.org/0000-0002-1223-503X)
- Florian Trybel (ORCID: https://orcid.org/0000-0003-0514-5084)
Institutions
- Linköping University (SE)
- Goethe University Frankfurt (DE)
- Deutsches Elektronen-Synchrotron DESY (DE)
- European Synchrotron Radiation Facility (FR)
- University of Edinburgh (GB)
Publication Details
- Journal
- Journal of the American Chemical Society
- Published
- 2025-09-18
- DOI
- https://doi.org/10.1021/jacs.5c09198
- Citations
- 2
- Primary Topic
- Crystallography and molecular interactions
- Type
- article
- Field-Weighted Citation Impact
- 3.51