Hydrogen disorder in kaatialaite from Jáchymov, Czech Republic

database, nuove specie, discrediti,
ridefinizioni, classificazioni, ecc.
Rispondi
Avatar utente
Marco E. Ciriotti
Messaggi: 27488
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Hydrogen disorder in kaatialaite from Jáchymov, Czech Republic

Messaggio da Marco E. Ciriotti » mar 12 gen, 2021 20:23

Referenza:
▪ Steciuk, G., Majzlan, J., Plášil, J. (2021): Hydrogen disorder in kaatialaite Fe[AsO2(OH)2]5H2O [flash=]from Jáchymov, Czech Republic[/flash]: determination from low-temperature 3D electron diffraction. IUCrJ, 8, 116-123; https://doi.org/10.1107/S2052252520015626

Abstract:
Kaatialaite mineral Fe[AsO2(OH)2]5H2O from Jáchymov, Czech Republic forms white aggregates of needle-shaped crystals with micrometric size. Its structure at ambient temperature has already been reported but hydrogen atoms could not be identified from single-crystal X-ray diffraction. An analysis using 3D electron diffraction at low temperature brings to light the hydrogen positions and the existence of hydrogen disorder. At 100 K, kaatialaite is described in a monoclinic unit cell of a = 15.46, b = 19.996, c = 4.808 Å, β = 91.64° and V = 1485.64 Å3 with space group P21/n. The hydrogen sites were revealed after refinements both considering the dynamical effects and ignoring them. The possibility to access most of the hydrogen positions, including partially occupied ones among heavy atoms, from the kinematical refinement is due to the recent developments in the analysis of 3D electron data. The hydrogen bonding observed in kaatialaite provides examples of H2O configurations that have not been observed before in the structures of oxysalts with the presence of unusual inverse transformer H2O groups.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Rispondi

Chi c’è in linea

Visitano il forum: Google [Bot] e 6 ospiti