Kristallstruktur von MgSO 3 ·H2 O /Crystal Structure of Mg SO 3 ·H 2 O

The crystal structure of MgSO 3 ·H 2 O , space group P2 1 /ln, Z = 4, D x = 2.415 g·cm -3 , a = 4.699(1), b = 12.751(3), c = 5.618(1) Å, β = 90.49(3)°, was determined by single crystal X-ray diffraction. MgSO 3 ·H 2 O crystallizes in the MnSO 3 ·H 2 O type. The structure consists of buckled trans layers ∞ [MgSO 3 ·H 2 O], which are built up from strongly distorted MgO 5 (H 2 O) octahedra sharing four equatorial vertices, and of trigonal pyramidal SO 3 2- ions. It is close­ly related to the structures of orthorhombic MnSeO 3 ·D 2 O and monoclinic ZnSeO 3 ·H 2 O . The Mg-O distances range from 2.051(3) to 2.175(4) Å. The S-O distances (1.543(3), 1.547(3) and 1.493(3) Å) and the O-S-O angles (98.4(2) and 2x 106.0(2)°) correspond to those in MnSO 3 ·H 2 O . The distortion of the MO 5 (H 2 O) octahedra (M = Mg, Mn) and of the SO 3 2- ions is smaller in MgSO 3 ·H 2 O , but with greater deviations from m symmetry. The distances between the H-connected ∞ 2 [MSO 3 ·H 2 O] layers are greater in MgSO 3 ·H 2 O , indicating weaker inter-layer hydrogen bonds. The lateral arrangement of the ∞ 2 [MSO 3 ·H 2 O] layers is nearly the same in both sulfite monohydrates.