| Abstract: | Hydrogen Sulfates with Disordered Hydrogen Atoms – Synthesis and Structure of LiH(HSO4)2](H2SO4)2 and Refinement of the Structure of α-NaHSO4 The structure of LiH(HSO4)2](H2SO4)2 has been determined for the first time whereas the structure of α-NaHSO4 has been refined, so that direct determination of the hydrogen positions was possible. Both compounds crystallize triclinic in the space group P1 with the lattice constants a = 6.708(2), b = 6.995(1), c = 7.114(1) Å, α = 75.53(1), β = 84.09(2) and γ = 87.57(2)° (Z = 4) for α-NaHSO4 and a = 4.915(1), b = 7.313(1), c = 8.346(2) Å, α = 82.42(3), β = 86.10(3) and γ = 80.93(3)° (Z = 1) for LiH(HSO4)2](H2SO4)2. In both compounds there are disordered hydrogen positions. In the structure of α-NaHSO4 there are two crystallographically different HSO4? tetrahedra and two different coordinated 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 Å) while in the ordered HSO4 unit “regular” bond lengths are observed (1.45 und 1,57 Å). In the structure of LiH(HSO4)2](H2SO4)2 there are two crystallographically different SO4-tetrahedra. The first one belongs to the H(HSO4)2]? unit while the second one represents 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 Å. Li is located on a symmetry centre and is slightly distorted octahedrally coordinated by oxygen atoms of six different SO4 tetrahedra. The system of hydrogen bonds can be regarded as consisting of double layers parallel to the xy-plane. |
