Structure of hydrated and sulfated stannous acid. Quantum chemical modeling

Different complexes of H2SnO3 and its hydrated and sulfated derivatives were studied by the quantum chemical method within the framework of the cluster approximation with the ωB97XD functional and LanL2DZ(Sn), 6-31G**(O,S,H) basis sets, and with periodic boundary conditions approach with the PBE functional and the basis of the projector-augmented plane waves. It was found that among the hydrated forms, the smallest clusters with features of a SnO2 crystal (twofold and threefold coordinated oxygen atoms and fivefold and sixfold coordinated tin atoms) are (H2SnO3)6 clusters with a diameter of the described sphere d ~ 10 Å.Their combination (in the form of globules (d ~ 20 Å), chains, films) due to hydrogen bonds with each other and water molecules is energetically favorable. It is also possible their consolidation due to covalent Sn–O–Sn and Sn–OH–Sn bonds with the formation of various larger nanoparticles, for example (H2SnO3)12.The interesting thing is that some of them are hollow structures.Sulfuric acid molecules adsorbed on the surface of (SnO2)n(H2O)m clusters are bound to the surface Sn atoms by SO4 2– anions, and the protons split off in this case complete the conduction channels, forming H3O+ and H5O2 + cations in them in addition to OH-anions and water.