Structure of the high-temperature phase of caesium nitrate – the importance of high-resolution data

0556955 - FZÚ 2023 RIV GB eng J - Journal Article
Fábry, Jan - Kučeráková, Monika - Dušek, Michal - Buixaderas, Elena - Hlinka, Jiří
Structure of the high-temperature phase of caesium nitrate – the importance of high-resolution data.
Acta Crystallographica Section B-Structural Science Crystal Engineering and Materials. Roč. 78, č. 2 (2022), s. 140-152. E-ISSN 2052-5206
R&D Projects: GA ČR GX19-28594X
Institutional support: RVO:68378271
Keywords : alkali nitrates * positional disorder * twelve-orientation model * eight-orientation aragonite model * difference electron-density maps
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 1.9, year: 2022
Method of publishing: Limited access
https://doi.org/10.1107/S2052520622001135

A single-crystal structure determination of the cubic phase of CsNO3 based on data collected at 439 K up to sinθmax/λ = 0.995000 reciprocal Angstroem, i.e. to an unprecedentedly high-θ value, is reported. The structure has been refined in Pm3m (Z = 1). Analysis of the difference electron-density maps revealed that the most appropriate model is the twelve-orientation model with the Cs, N, O1 and O2 atoms situated on the Wyckoff positions 1a, 6f, 6f and 24l, respectively, rather than the eight-orientation aragonite model with the Cs, N and O atoms situated on the Wyckoff positions 1a, 8g and 24m, respectively. Both models, however, show close similarities if the large anisotropic displacement parameters of the O atoms in the eight-orientation aragonite model are taken into account. The reason for this is shown to lie in the smeared electron density around the positions of the disordered nitrate anion.
Permanent Link: http://hdl.handle.net/11104/0331074