Crystal structure and characterization of magnesium carbonate chloride heptahydrate. Issue 8 (8th July 2020)

• Record Type: Journal Article
• Authors: Rincke, Christine; Schmidt, Horst; Buth, Gernot; Voigt, Wolfgang
• Is Part Of: Acta crystallographica. Volume 76:Issue 8(2020)
• Page Start: 741
• Page End: 745
• Publication Date: 2020-07-08
• Subjects: magnesium -- carbonate -- chloride -- hydrate -- synchrotron -- twinning -- crystal structure; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229620008153
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : The structure of the stable double salt MgCO3 ·MgCl2 ·7H2 O, obtained from concentrated solutions of MgCl2, is characterized by double chains of MgO octahedra and carbonate ions parallel to (100), interconnected by chloride ions. Abstract : MgCO3 ·MgCl2 ·7H2 O is the only known neutral magnesium carbonate containing chloride ions at ambient conditions. According to the literature, only small and twinned crystals of this double salt could be synthesised in a concentrated solution of MgCl2 . For the crystal structure solution, single‐crystal diffraction was carried out at a synchrotron radiation source. The monoclinic crystal structure (space group Cc ) exhibits double chains of MgO octahedra linked by corners, connected by carbonate units and water molecules. The chloride ions are positioned between these double chains parallel to the (100) plane. Dry MgCO3 ·MgCl2 ·7H2 O decomposes in the air to chlorartinite, Mg2 (OH)Cl(CO3 )· n H2 O ( n = 2 or 3). This work includes an extensive characterization of the title compound by powder X‐ray diffraction, thermal analysis, SEM and vibrational spectroscopy.