HYDROGEN SULFATES WITH DISORDERED HYDROGE N-ATOMS - SYNTHESIS AND STRUCTURE OF LI[H(HSO4)(2)](H2SO4)(2) AND REFINEMENT OF THE STRUCTURE OF ALPHA-NAHSO4

The structure of Li[H(HSO4)(2)](H2SO4)(2) has been determined for the first time whereas the structure of alpha-NaHSO4 has been refined, so that direct determination of the hydrogen positions was possible. Both compounds crystallize triclinic in the space group P (1) over bar wit h the lattice constants a = 6.708(2), b = 6.995(1), c = 7.114(1) Angst rom, alpha = 75.53(1), beta = 84.09(2) and gamma = 87.57(2)degrees (Z = 4) for alpha-NaHSO4 and a = 4.915(1), b = 7.313(1), c = 8.346(2) Ang strom, alpha = 82.42(3), beta = 86.10(3) and gamma = 80.93(3)degrees ( Z = 1) for Li[H(HSO4)(2)](H2SO4)(2). In both compounds there are disor dered hydrogen positions. In the structure of alpha-NaHSO4 there are t wo crystallographically different HSO4- tetrahedra and two different c oordinated Na atoms. The system of hydrogen bonds can be described by chains in [0-11] direction. The disordering of the H atoms reduces the differences between the S-O and S-OH distances (1.45 and 1.50 Angstro m) while in the ordered HSO4 unit ''regular'' bond lengths are observe d (1.45 und 1,57 Angstrom). In the structure of Li[H(HSO4)(2)](H2SO4)( 2) there are two crystallographically different SO4-tetrahedra. The fi rst one belongs to the [H(HSO4)(2)](-) unit while the second one repre sents H2SO4 molecules. The H atom which is located nearby the symmetry centre and connects two HSO4 units by a short O...O distance of 2.44 Angstrom. Li is located on a symmetry centre and is slightly distorted octahedrally coordinated by oxygen atoms of six different SO4 tetrahe dra. The system of hydrogen bonds can be regarded as consisting of dou ble layers parallel to the xy-plane.