Variation of oxygen content in selected potassium fluorido-oxido-tantalate phases

• Published in: Solid state sciences 2011-12, Vol.13 (12), p.2190-2195
• Main Authors: Boča, Miroslav, Moncoĺ, Ján, Netriová, Zuzana, Velič, Dušan, Jerigová, Monika, Nunney, Tim S., Baily, Christopher J., Kubíková, Blanka, Šimko, František, Janderka, Pavel
• Format: Article
• Language: English
• Subjects: Atomic structure; Cations; Condensed matter: structure, mechanical and thermal properties; Crystal structure; Disorders; Exact sciences and technology; Fluorido-oxido-tantalates; Oxo-fluoro-tantalates; Oxygen content; Phases; Physics; Secondary ion mass spectrometry; SIMS; Structure; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; X-ray photoelectron spectroscopy; XPS; XRD
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2011.10.006

The compound K 3[TaO 4]∙K 3[TaF 4O 2] crystallises in a tetragonal system (space group I-4) with cell parameters a = 6.2220(3) Å and c = 8.7625(34) Å, respectively. The crystal structure consists of two anions, [TaO 4] 3− and [TaF 4O 2] 3− and cations K +. The tantalum atoms lie in special positions and serve as centres of both anions, which are substitution disorders. XPS measurements confirmed the existence of different binding energies corresponding to the different bonds of Ta O and Ta F. Oxygen is bound more strongly in [TaF 4O 2] 3−. By combination of single crystal analysis, XRD, SIMS and XPS it was suggested that previously reported cubic phase K 3TaOF 6 is in fact K 3TaO 2F 4 and previously reported tetragonal phase K 3TaO 2F 4 is in fact K 3[TaO 4]∙K 3[TaF 4O 2]. The disordered parts of anion [TaF 4O 2] 3− are drawn solid line (main part) and open solid line (minor part). [Display omitted] ► Single crystal analysis of K 3[TaO 4] K 3[TaF 4O 2]. ► The crystal structure consists of two anions, [TaO 4] 3− and [TaF 4O 2] 3− and cations K +. ► XRD, SIMS and XPS supporting spectroscopies.