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Updated: Feb 21, 2026

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Phase transition sequences in tetramethylammonium tetrachlorometallates by X-ray diffraction and spectroscopic
Jack Binns1, Garry J McIntyre2, José A Barreda-Argüeso3
1EaStCHEM School of Chemistry and Centre for Science at Extreme Conditions, The University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3FJ, Scotland.
Abstract:
The phase transition sequences of two members of the tetramethylammonium tetrachlorometallate(III) family of hybrid organic-inorganic salts have been determined and structurally characterized as a function of temperature for the first time. Unusually, a reduction in point-group symmetry with increasing temperature until reaching a cubic prototype phase is observed. Two additional intermediate phases are observed for Fe3+. First-principles calculations and the presence of short Cl...Cl contacts for Ga3+ suggest the [GaCl4]- anion to be conformationally hindered due to stronger lone-pair-σ-hole interactions. The conformationally more flexible Fe3+ structures show sublattice melting with the onset of rotational disorder in the [NMe4]+ cations occurring 40 K below the corresponding onset of rotational disorder in the [FeCl4]- sublattice.
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