Arsenic nitride, the crystal that did not exist

Arsenic nitride, the crystal that did not exist

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An international research group including researchers from the Institute of Chemistry of Organometallic Compounds of the National Research Council (CNR-ICCOM), from the European Laboratory for Non-Linear Spectroscopy (LENS) in Sesto Fiorentino, from the European Synchrotron Radiation Facility (ESRF) of Grenoble (France) and the Chemistry Departments of the Universities of Florence and Pavia, managed to induce a chemical reaction between arsenic and molecular nitrogen in the absence of solvents or catalysts and to synthesize for the first time a crystalline arsenic nitride of chemical formula AsN. This reaction, which does not occur under normal conditions, was obtained under very high pressure and temperature conditions (300,000 times the atmospheric pressure and about 1200 ° C), using diamond anvil cells in combination with laser heating techniques. The results were recently published in the journal Angew. Chem. Int. Ed.

The crystal obtained has characteristics similar to those of a form of nitrogen called cubic-gauche nitrogen (cg-N), which is considered one of the most energy-dense materials, with potential applications as an explosive or propellant in aerospace engineering and sustainable mobility with low environmental impact.

The structure of the arsenic nitride (AsN) crystal was determined by synchrotron source X-ray diffraction (XRD) techniques at ESRF. The data acquired during the experiments indicate the persistence of this new compound up to pressures as high as one hundred thousand times the atmospheric pressure at room temperature, suggesting the possibility to recover AsN at ambient pressure. The synthesis conditions applied in the study are enormously lower than the extreme pressure and temperature conditions required for the synthesis of cg-N (more than one million times the atmospheric pressure and ~ 1700 ° C).

The implications of the discovery of arsenic nitride AsN concern both the fundamental chemistry of the elements of group 15 of the Periodic Table and the high-pressure synthesis of innovative advanced materials such as thermoelectrics and materials with very low thermal conductivity, opening new perspectives for the study. of these high pressure systems. The published article can be downloaded at the following link:

Matteo Ceppatelli, Demetrio Scelta, Manuel Serrano-Ruiz, Kamil Dziubek, Marta Morana, Volodymyr Svitlyk, Gaston Garbarino, Tomasz Poręba, Mohamed Mezouar, Maurizio Peruzzini, Roberto Bini. “Single-Bonded Cubic AsN from High-Pressure and High-Temperature Chemical Reactivity of Arsenic and Nitrogen”. Angew. Chem. Int. Ed. 2022, earlyview article. DOI: 10.1002/anie.202114191.