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and a separate O2- anion. This comparison underscores the distinct crystal chemistry of carbon compared to silicon under mild pressures.
This research not only introduces a new class of compounds but also demonstrates the power of high-pressure chemistry in discovering and stabilizing exotic anions like CN₃5-. Indeed, one of the most remarkable findings of this study is the stability of the CN₃5- guanidinate anion at ambient conditions, a significant achievement considering its synthesis under extreme pressure and temperature. The ability to recover these compounds to normal conditions without significant degradation, and the unique structure and stability of the CN₃5- anion, opens up new avenues for research and synthesis, with the potential for further upscaling and applications in various fields of chemistry.
PRINCIPAL PUBLICATION AND AUTHORS
Stabilization of the CN35- anion in recoverable high-pressure Ln3O2(CN3) (Ln = La, Eu, Gd, Tb, Ho, Yb) oxoguanidinates, A. Aslandukov (a), P.L. Jurzick (b), M. Bykov (b,c), A. Aslandukova (a), A. Chanyshev (a), D. Laniel (d), Y. Yin (a), F.I. Akbar (a), S. Khandarkhaeva (a), T. Fedotenko (d), K. Glazirin (d), S. Chariton (e), V. Prakapenka (e), F. Wilhelm (f), A. Rogalev (f), D. Comboni (f), M. Hanfland (f), N. Dubrovinskaia (a), L. Dubrovinsky (a), Angew. Chem. Int. Ed. 62, 47, e202311516 (2023); https:/doi.org/10.1002/anie.202311516 (a) University of Bayreuth, Bayreuth (Germany) (b) University of Cologne, Cologne (Germany) (c) Goethe University Frankfurt, Frankfurt (Germany) (d) DESY, Hamburg (Germany) (e) APS, Lemont (USA) (f) ESRF (g) Linköping University, Linköping (Sweden)
The novel synthesis approach also paves the way for the development of other guanidinates and perhaps ortho-nitridocarbonates at even higher pressures with promising applications such as enhanced photochemical water-splitting, catalysis, optoelectronics, and energy storage. The discovery of this new C-N anion could even hold implications for planetary science, as compounds containing such an anion may exist within the interiors of exoplanets.
Fig. 34: La LII-edge XANES spectra of La3O2(CN3) sample at 25 GPa and La2O3 reference sample at ambient conditions. The position of white lines is 5897 eV in both spectra, indicating the same +3 oxidation state of La in these compounds. The low signal-to-noise ratio in the spectrum of La3O2(CN3) is because the measurements were carried out in a DAC, and 2 mm-thick diamonds absorb 98 % of the X-ray radiation at these energies.
