Synthesis and structural characterization of the hexagonal anti-perovskite Na{sub 2}CaVO{sub 4}F

Journal Article · Thu Jun 15 00:00:00 EDT 2017 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2017.03.027· OSTI ID:22658297

Avdeev, Maxim ^[1]; Vogt, Thomas ^[2]

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1. Australian Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)
2. NanoCenter and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States)

The structural details of the ordered hexagonal oxyfluoride Na{sub 2}CaVO{sub 4}F prepared by solid-state synthesis using stoichiometric amounts of V{sub 2}O{sub 5}, CaCO{sub 3}, Na{sub 2}CO{sub 3} and NaF were characterized using high-resolution neutron powder diffraction. The structural changes between 25 °C and 750 °C revealed that the two structural subunits in this material behave different when heated: there is an expansion of the face-shared FNa{sub 4}Ca{sub 2} octahedra while the VO{sub 4} tetrahedra due to increased thermal disorder reveal marginal bond contractions. Bond valences and the global instability index point to significant structural disorder at 750 °C. - Graphical abstract: The structure of the novel oxyfluoride Na{sub 2}CaVO{sub 4}F is studied at room temperature and high-temperatures. The structure can be viewed as layers of compression and elongation of polyhedral subunits, which change as a function of temperature. - Highlights: • The novel oxyfluoride, Na{sub 2}CaVO{sub 4}F, is synthesized via solid-state method. • High-resolution neutron diffraction data is used to analyze the structure of Na{sub 2}CaVO{sub 4}F. • Structural subunits exhibit expansion and contraction with increasing temperature. • Higher temperatures increase instability within the structure of Na{sub 2}CaVO{sub 4}F.

• OSTI ID: 22658297
• Journal Information: Journal of Solid State Chemistry, Vol. 250; Other Information: Copyright (c) 2017 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
CALCIUM CARBONATES
CARBON IONS
NEUTRON DIFFRACTION
OXYFLUORIDES
SODIUM CARBONATES
SODIUM FLUORIDES
SYNTHESIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
VANADIUM OXIDES