Structural Studies of New Sulfito Mercurates(II) with General Formula xM[XHgSO3]middot;yHgX2·zMX·nH2O (M = NH4, K; X = Cl, Br)

• Published in: Zeitschrift für anorganische und allgemeine Chemie (1950) 2008-08, Vol.634 (10), p.1742-1748
• Main Authors: Weil, Matthias, Baumann, Stefan, Breitinger, Dietrich K.
• Format: Article
• Language: English
• Subjects: Crystal structures; Mercury; Sulfito ligands
• ISSN: 0044-2313; 1521-3749
• DOI: 10.1002/zaac.200800159

Several solid phases with the general formula xM[XHgSO3]·yHgX2·zMX·nH2O were obtained from aqueous solutions during phase formation studies in the systems M2SO3/HgX2 (M = NH4, K; X = Cl, Br). All phases were structurally characterized on the basis of single crystal X‐ray diffraction data and adopt new structure types. Compounds with x, y, z = 1 and n = 0 are isostructural (structure type I) and crystallise with two formula units in space group P21/m and lattice parameters of a ≈ 9.7, b ≈ 6.2, c ≈ 10.4Å, β ≈ 111°. Compounds with x, y = 1 and z, n = 0 (structure type II) crystallize in space group Cmc21 with four formula units and lattice parameters of a ≈ 5.9, b ≈ 22.0, c ≈ 6.9Å. The structures with x = 2, y, z = 1 and n = 0 are likewise isostructural (stucture type III) and consist of four formula units in space group Pnma with lattice parameters of a ≈ 22.2, b ≈ 6.1, c ≈ 12.4Å. K[HgSO3Cl]·KCl·H2O is the only representative where x = 1, y = 0, z = 1 and n = 1 (structure type IV). It is triclinic (space group $P{\bar 1}$) with four formula units and lattice parameters of a = 6.1571(8), b = 7.1342(9), c = 10.6491(14) Å, α = 76.889(2), β = 88.364(2), γ = 69.758(2)°. Characteristic for all structures types is the segregation of the M+ cations and the anions and/or HgX2 molecules into layers. The [XHgSO3]− anions are present in all structures and have m symmetry, except for K[HgSO3Cl]·KCl·H2O with 1 symmetry (but very close to m symmetry). The different [XHgSO3] units exhibit very similar Hg‐S distances (average 2.372Å) and are more or less bent with ∠(X‐Hg‐S) angles ranging from 159.7 to 173.7°. The molecular HgX2 entities present in structure types I‐III deviate only slightly from linearity with ∠(X‐Hg‐X) angles ranging from 174 to 179°. The structures are stabilised by interaction of the K+ or NH4+ cations that are located between the anionic layers or in the vacancies of the framework, by K‐O contacts or, in case of ammonium compounds, by medium to weak hydrogen bonding interactions of the type N‐H···O.