Simulation of proton transport in orthoiodic and orthotelluric acids and in their salts

Calculations of orthoiodic and orthotelluric acids, their salts MIO6H4 (M = Li, Rb, Cs) and CsH5TeO6, as well as of the salt · acid type dimers, were made in the framework of the density functional theory. The calculations indicated that the salt · acid dimerization for the calculated compounds MIO6H4 · H5IO6 (M = Rb, Cs) and CsIO6H4 · H6TeO6 is beneficial from energy viewpoint. Dimerization energy amounts to 138-146 kJ/mol. In case of relatively low activation energies equal to 4 kJ/mol (M = Li) and 11 kJ/mol (M = Rb, Cs) rotation of IO6 octahedron in reference to M atom in monomers of salt molecules is possible. Proton transfer along the octahedron is made with activation energies of 63-84 kJ/mol. Activation energy of proton transfer between adjacent octahedrons of the salt · acid → acid · salt type makes up 8-17 kJ/mol