Synthesis and structural investigation of a new oxide fluoride of composition Ba{sub 2}SnO{sub 2.5}F{sub 3}.xH{sub 2}O (x{approx}0.5)

Journal Article · Mon Sep 15 00:00:00 EDT 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.05.015· OSTI ID:21128430

Berry, Frank J; Moore, Elaine ^[1]; Mortimer, Michael ^[1]; Xiaolin, Ren ^[1]; Heap, Richard; Slater, Peter ^[2]; Thomas, Michael F ^[3]

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1. Department of Chemistry and Analytical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)
2. Department of Chemistry, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)
3. Department of Physics, University of Liverpool, Liverpool L69 3BX (United Kingdom)

The preparation of a new oxide fluoride of composition Ba{sub 2}SnO{sub 2.5}F{sub 3}.xH{sub 2}O (x{approx}0.5) from the low-temperature (240 deg. C) reaction between Ba{sub 2}SnO{sub 4} and ZnF{sub 2} is reported. X-ray and neutron powder diffraction showed fluorination to result in a significant enlargement along the c-axis (by ca. 3 A) of the unit cell of the precursor oxide. A structural model based on the perovskite-related K{sub 2}NiF{sub 4}-type structure of this oxide is proposed in which there is direct replacement of oxygen in octahedral SnO{sub 6} units by fluorine, as well as the presence of F{sup -} at interstitial sites between BaO rock salt layers. Atomistic computer modelling indicates that apical fluorine substitution is favoured. The structural model is supported by the results of {sup 19}F and {sup 119}Sn MAS NMR spectroscopy as well as tin K- and barium K-edge EXAFS. Thermal analysis revealed the presence of water in the synthesized material and this is assigned to interstitial sites. {sup 119}Tin Moessbauer spectroscopy and tin K-edge XANES are consistent with enhanced withdrawal by substituted fluorine of electron density from Sn{sup 4+}. - Graphical abstract: The K{sub 2}NiF{sub 4}-type phase Ba{sub 2}SnO{sub 4} has been fluorinated at 240 deg. C using ZnF{sub 2} to give a new oxide fluoride of composition Ba{sub 2}SnO{sub 2.5}F{sub 3}.xH{sub 2}O (x{approx}0.5). A model in which fluorine occupies both interstitial and apical substitutional sites in the structure of the precursor oxide is supported by spectroscopic and diffraction information, combined with atomistic computer modelling studies.

• OSTI ID: 21128430
• Journal Information: Journal of Solid State Chemistry, Vol. 181, Issue 9; Other Information: DOI: 10.1016/j.jssc.2008.05.015; PII: S0022-4596(08)00253-3; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
BARIUM OXIDES
ELECTRON DENSITY
FINE STRUCTURE
FLUORINATION
FLUORINE IONS
INTERSTITIALS
LAYERS
MOESSBAUER EFFECT
NEUTRON DIFFRACTION
NUCLEAR MAGNETIC RESONANCE
PEROVSKITE
SALT DEPOSITS
SIMULATION
STRUCTURAL MODELS
SYNTHESIS
TEMPERATURE RANGE 0400-1000 K
THERMAL ANALYSIS
TIN COMPOUNDS
X-RAY SPECTROSCOPY
ZINC FLUORIDES