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Dehydration of the Sorel Cement Phase 3Mg(OH) 2 ·MgCl 2 ·8H 2 O studied by in situ Synchrotron X‐ray Powder Diffraction and Thermal Analyses
Author(s) -
Runčevski Tomče,
Dinnebier Robert E.,
Freyer Daniela
Publication year - 2014
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201300229
Subject(s) - dehydration , crystal structure , powder diffraction , magnesium , synchrotron , x ray crystallography , chemistry , thermal decomposition , crystallography , octahedron , atmospheric temperature range , diffraction , thermal analysis , phase (matter) , hydrate , molecule , thermal , thermodynamics , physics , organic chemistry , biochemistry , nuclear physics , optics
Dehydration is an important process which affects the chemical, physical and mechanical properties of materials. This article describes the thermal dehydration and decomposition of the Sorel cement phase 3Mg(OH) 2 · MgCl 2 · 8H 2 O, studied by in situ synchrotron X‐ray powder diffraction and thermal analyses. Attention is paid on the determination of the chemical composition and crystal structure of the lower hydrates, identified as the phases 3Mg(OH) 2 · MgCl 2 · 5.4H 2 O and 3Mg(OH) 2 · MgCl 2 · 4.6H 2 O. The crystal structure of 3Mg(OH) 2 · MgCl 2 · 4.6H 2 O is solved and refined by the Rietveld method and a structural model for the 3Mg(OH) 2 · MgCl 2 · 5.4H 2 O phase is given. These phases show statistical distribution of water molecules, hydroxide and chloride anions positioned as ligands on the magnesium octahedra. A structural scheme of the temperature induced transformations in the thermal range from 25 to 500 °C is presented.