Phase transition sequences in tetramethylammonium tetrachlorometallates by X-ray diffraction and spectroscopic measurements.

Autor: Binns J; EaStCHEM 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., McIntyre GJ; Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia., Barreda-Argüeso JA; CITIMAC-Malta Team, Facultad de Ciencias, University of Cantabria, Santander, 39005, Spain., González J; CITIMAC-Malta Team, Facultad de Ciencias, University of Cantabria, Santander, 39005, Spain., Aguado F; CITIMAC-Malta Team, Facultad de Ciencias, University of Cantabria, Santander, 39005, Spain., Rodríguez F; CITIMAC-Malta Team, Facultad de Ciencias, University of Cantabria, Santander, 39005, Spain., Valiente R; Dpto Física Aplicada, Facultad de Ciencias, University of Cantabria, Santander, 39005, Spain., Parsons S; EaStCHEM 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.
Jazyk: angličtina
Zdroj: Acta crystallographica Section B, Structural science, crystal engineering and materials [Acta Crystallogr B Struct Sci Cryst Eng Mater] 2017 Oct 01; Vol. 73 (Pt 5), pp. 844-855. Date of Electronic Publication: 2017 Aug 02.
DOI: 10.1107/S2052520617006412
Abstrakt: 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 Fe 3+ . First-principles calculations and the presence of short Cl...Cl contacts for Ga 3+ suggest the [GaCl 4 ] - anion to be conformationally hindered due to stronger lone-pair-σ-hole interactions. The conformationally more flexible Fe 3+ structures show sublattice melting with the onset of rotational disorder in the [NMe 4 ] + cations occurring 40 K below the corresponding onset of rotational disorder in the [FeCl 4 ] - sublattice.
Databáze: MEDLINE
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