STRUCTURAL CHEMISTRY OF METAL HYDROGEN SULFATES. S. Troyanov^a, C. Werner^b, E. Kemnitz^b, ^aMoscow State University, Chemistry Department, 119899 Moscow, Vorobjevy Gory, Russia, ^bHumboldt Universität Berlin, Institut für Anorganische Chemie, Hessische Str. 1-2, 10115 Berlin, Germany

A series of new hydrogen sulfates of general formula M^I_XH_NSO₄ and M^II_YH_NSO₄ have been synthesized and structurally characterized in the last few years. The general structural aspects are discussed using the value N which defines the average number of hydrogen donor functions (OH groups) per SO₄ tetrahedron.

All crystal structures contain M¹⁺ or M²⁺ ions coordinated by O atoms with CN's from 4 to 10 depending mainly on the metal radii. Counterparts consist of simple HSO₄^- tetrahedra or their combination with SO₄^2- or H₂SO₄ tetrahedra.

The S-O distances correlate with additional structural functions of O atoms such as coordination by M atom(s), H-acceptor, or H-donor functions. The S-OH distances are generally 0.1 Å longer than the S-O distances. Both S-O and S-OH distances are slightly longer (by 0.02-0.03 Å) in HSO₄^- as compared to those in the H₂SO₄ unit.

Every H atom forms a hydrogen bond O-H...O. The N value in the formula defines the main features of the hydrogen bonding systems: isolated or extended in one, two, or three directions. The connectivity patterns of the H bonding systems for the same N value can vary due to different distribution of acceptor functions between HSO₄^- and H₂SO₄ units.

The structures of [[alpha]]-NaHSO₄ and Li[H(HSO₄)₂](H₂SO₄)₂ contain disordered hydrogen bonds characterized by strong O...O interactions at the distances of 2.51 Å and 2.44 Å, respectively.