INVESTIGATION OF CHALCOGEN BONDING IN THE STRUCTURE OF SODIUM SELENITE Na2SeO3

10.25712/ASTU.1811-1416.2026.01.006

Abstract

The article presents a study of non-covalent chalcogen bonds Se···O in the crystal structure of sodium selenite (Na₂SeO₃). First synthesized in 1889 and studied in terms of its crystal structure only in the early 2000s, sodium selenite has not yet undergone detailed investigation of non-covalent chalcogen bonds. A quantum chemical calculation (DFT with periodic boundary conditions) of the sodium selenite crystal was performed using X-ray diffraction data. Topological analysis of the electron density revealed three critical points corresponding to chalcogen interactions. The study analyzed the geometric parameters of Se···O contacts, characteristic of chalcogen bonds, and showed that such interactions are indeed present in the structure of sodium selenite. The values of the total electron energy density Hb at the critical point are weakly positive, indicating the non-covalent nature of the interaction. To confirm the philicity of the interacting partners, an analysis of the one-electron potential (OEP) section was performed. On the OEP section, the bonding path between the selenium and oxygen atoms passes through the lone pair of the selenium atom and the lone pair of the oxygen atoms. The selenium atom acts as an electrophile, and the oxygen atom acts as a nucleophile.