SYNTHESIS AND STRUCTURE OF ZN(HSO4)2(H2SO 4)(2) AND CD(HSO4)(2)

From the binary systems M(2)SO(4)/H2SO4 (M = Zn, Cd), two new hydrogen sulfates, (Zn(HSO4)(2)(H2SO4)(2) and Cd(HSO4)(2), have been synthesiz ed and structurally characterized. Both compounds crystallize in the m onoclinic space group P2(1)/c with cell parameters a = 5.047(2), b = 1 5.430(4), c = 7.958(3) Angstrom and beta = 104.16(4)degrees (Z = 2) fo r Zn(HSO4)(2)(H2SO4)(2) and a = 5.339(1), b = 13.351(3), c = 8.508(2) Angstrom and beta = 92.22(3)degrees (Z = 4) for Cd(HSO4)(2). In the zi nc compound there are slightly distorted centrosymmetric ZnO6 octahedr a with Zn-O distances of 2.05 - 2.13 Angstrom which are sharing corner s with SO4 tetrahedra. HSO4 and H2SO4 tetrahedra are linked via hydrog en bonds to form layers perpendicular to the c-axis. In the crystal st ructure of Cd(HSO4)(2) there exist two crystallographically different HSO tetrahedra. The CdO6 octahedra with Cd-O distances between 2.24 an d 2.31 Angstrom are strongly angle-distorted. Besides hydrogen bonds o f medium strength (d(O ... O) = 2.66 Angstrom) there are also much mor e weaker ones (d(O ... O) = 3.04 Angstrom). Considering these latter o nes zigzag chains in z-direction can be recognized. The relatively low stability of Cd(HSO4)(2) in comparison wi th other metal-II-hydrogen sulfates is discussed with respect to its structural pecularities.