Crystal structure of magnesium dichloride decahydrate determined by X‐ray and neutron diffraction under high pressure. Issue 1 (1st February 2015)

• Record Type: Journal Article
• Authors: Komatsu, Kazuki; Shinozaki, Ayako; Machida, Shinichi; Matsubayashi, Takuto; Watanabe, Mao; Kagi, Hiroyuki; Sano‐Furukawa, Asami; Hattori, Takanori
• Is Part Of: Acta crystallographica. Volume 71:Issue 1(2015:Feb.)
• Page Start: 74
• Page End: 80
• Publication Date: 2015-02-01
• DOI: 10.1107/S205252061500027X
• Languages: English
• ISSNs: 2052-5206

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Magnesium dichloride decahydrate (MgCl₂·10H₂O) and its deuterated counterpart (MgCl₂·10D₂O) are identified for the first time by <italic>in‐situ</italic> powder synchrotron X‐ray and spallation neutron diffraction. These substances are crystallized from a previously unidentified nanocrystalline compound, which originates from an amorphous state at low temperature. A combination of a recently developed autoindexing procedure and the charge‐flipping method reveals that the crystal structure of MgCl₂·10H₂O consists of an ABCABC... sequence of Mg(H₂O)₆ octahedra. The Cl⁻ anions and remaining water molecules unconnected to the Mg²⁺ cations bind the octahedra, similar to other water‐rich magnesium dichloride hydrates. The D positions in MgCl₂·10D₂O, determined by the difference Fourier methods using the neutron powder diffraction patterns at 2.5 GPa, show the features such as bifurcated hydrogen bonds and tetrahedrally coordinated O atoms, which were not found in other forms of magnesium chloride hydrates.</p> </abstract>