Die Kristallstruktur des Magnesiumoctachlorotrimercurat(II)‐hexahydrates MgHg₃Cl₈ · 6 H₂O

Abstract

Farblose Kristalle von MgHg3Cl8 · 6 H2O wurden durch Kristallisation aus wäßrigen Lösungen von MgCl2 und HgCl2 erhalten. Für die Existenz der früher beschriebenen Verbindungen MgHgCl4 · 6 H2O und MgHg2Cl6 · 6 H2O ergaben sich keine Hinweise. Die Kristallstruktur des triklinen MgHg3Cl8 · 6 H2O (Raumgruppe P1; a = 911,2(6); b = 723,8(7); c = 749,5(5) pm; α = 100,15(5)°; β = 99,97(7)°; γ = 89,86(4)°; Z = 1; dpyk = 3,53 g cm−3; dber = 3,60 g cm−3) wird aus linearen Pseudo‐HgCl2‐Molekülen, zweikernigen Hg2Cl6‐Anionen und oktaedrischen Mg(OH2)6‐Kationen aufgebaut.

Bis(triphenyltellurium) di-μ-chloro-bis[dichloromercurate(II)], [Te(C6H5)3+]2[Hg2Cl62−]

“…One other feature is a significant asymmetry in the Hg thermal vibration; UI1 = 0.1325 (4)A 2 corresponds to a r.m.s, displacement of 0.36 A. Deviations from P1 symmetry seem unlikely, since no Friedel pair differences were observed, and the parameter probably corresponds to a real vibration in a direction approximately bisecting the large CI(1)-Hg-CI(3) angle of 141 °. The overall geometry and dimensions of the anion are similar to those found previously for Hg2X~6-species (Beurskens, Bosman & Cras, 1972;Brotherton, Epstein, White & Willis, 1974;von Brodersen, Pezzei & Thiele, 1983 …”

Bis(tetraethylammonium) di-μ-bromo-bis[dibromomercurate(II)], (Et4N)2[Hg2Br6]

“…This type of distorted tetrahedral coordination is also found in other complexes with discrete dimeric [Hg 2 X 6 ] 2À units (X = Cl, Br, I), e.g. in MgHg 3 Cl 8 Á6H 2 O (Brodersen et al, 1983), (Ph 3 AsOH) 2 HgBr 4 (Harris et al, 1967) and (NEt 4 )[HgI 3 ] (Goggin et al, 1982). In (I), charge balance is achieved by ordered [Et 4 N] + cations ( Fig.…”

“…); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97. (White, 1963 (Brodersen et al, 1983), (Ph 3 AsOH) 2 HgBr 4 (Harris et al, 1967) and (NEt 4 )[HgI 3 ] (Goggin et al, 1982). In (I), charge balance is achieved by ordered [Et 4 N] + cations, which are quite remote from the anions although there are H atoms in the range 2.7-3.1 Å from Br − , with Br•••H-C angles in the range 160-170°.…”

Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement Systems

“…The observed solids are the metastable assemblage predicted at slightly lower pH (<11.8) and suggest that the system may not have reached equilibrium with respect to solid phases. Prior work noted the slow kinetics of Fe-ettringite formation (180 days to reach equilibrium) relative to Al-ettringite, and the initial formation of ferrihydrite and gypsum in Al-free systems. , There is also uncertainty in both the stoichiometries and solubilities of hydrated Ca–Fe hydroxysulfate phases that may form at high pH, , which would change the positions of the stability fields shown in Figure B. In the Fe-cpt without Hg, a Ca–Fe-sulfate-hydrate phase (of different stoichiometry than the phase used in the thermodynamic database) and calcite (as a minor phase) were identified as reaction products by XRD.…”

“…Chloromercury salts exhibit a wide structural diversity and variable composition . Although most structural characterization has been performed on organo-Hg salts, Hg x Cl y n – stoichiometries were identified in inorganic salts, such as the “double salt” [CaCl 2 ] 2 [HgCl 2 ] 11 •16H 2 O containing [Hg 6 Cl 13 – ]­[Hg 5 Cl 13 3‑ ] clusters, or the MgHg 3 Cl 8 salt . A range of Hg–Cl distances have been reported, depending on whether Cl is bridging between Hg atoms, with longer distances in general when Cl acts as a bridge .…”