Phase transition sequences in tetramethylammonium tetrachlorometallates by x-ray diffraction and spectroscopic measurements
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Date
2017-01
Journal Title
Journal ISSN
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Publisher
International Union of Crystallography
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. © International Union of Crystallography
Description
Keywords
Phase transformations, Crystal structure, Intermolecular forces, Salts, X-ray diffraction, Iron compounds, Gibberellic acid, Chlorides
Citation
Binns, J., McIntyre, G. J., Barreda-Argüeso, J. A., González, J., Aguado, F., Rodríguez, F., Valiente, R., & Parsons, S. (2017). Phase transition sequences in tetramethylammonium tetrachlorometallates by x-ray diffraction and spectroscopic measurements. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, B73, 844-855. doi:10.1107/S2052520617006412