Hydroniumjarosite, (H<sub>3</sub>O)<sup>+</sup> Fe<sub>3</sub>(SO<sub>4</sub>)<sub>2</sub>(OH)<sub>6</sub>, from Cerros Pintados, Chile
- Author(s)
- Jakub Plasil, Radek Skoda, K. Fejfarová, J. Cejka, A.V. Kasatkin, M. Dusek, Dominik Talla, L. Lapčák, V. Machovic, M. Dini
- Abstract
The natural hydroniumjarosite sample from Cerros Pintados (Chile) was investigated by electron microprobe, single-crystal X-ray diffraction and vibrational spectroscopy (Infrared and Raman). The chemical composition of studied specimens (wt.%, mean of seven analyses) obtained from electron microprobe (in wt.%): Na
2O 1.30, K
2O 0.23, CaO 0.04, Fe
2O
3 50.49, Al
2O
3 0.37, SiO
2 0.33, SO
3 33.88, H
2O (calculated on the basis of ∑(OH
-+H
3O
+) deduced from the charge balance) 13.32, total 99.98, corresponds to the empirical formula (H
3O)
0.77
+(Na
0.20K
0.02) S
0.22(Fe
2.95Al
0.03)∑
2.98 (OH)
6.12[(SO
4)
1.97(SiO
4)
0.03]
∑2.00 (calculated on the basis of S + Si = 2 a.p.f.u. (atoms per formula unit)). The studied hydroniumjarosite is trigonal, with space group R3̄m, with a = 7.3408(2), c = 17.0451(6) Å and V = 795.46(4) Å
3. The refined structure architecture is consistent with known jarosite-series minerals, including synthetic hydroniumjarosite. However, in the current study the presence of H
3O
+ is well documented in difference Fourier maps, where characteristic positive difference Fourier maxima, with apparent trigonal symmetry, were localized in the vicinity of the O4 atom in the channel-voids of the structure. The structure of natural hydroniumjarosite, including the H atoms, was refined to R
1 = 0.0166 for 2113 unique observed reflections, with I
obs>3σ(I). The present structure model, which includes the position of the H atom within the hydronium ion, is discussed with regard to the vibration spectroscopy results and earlier published density-functional theory (DFT) calculations for the alunite-like structure containing H
3O
+.
- Organisation(s)
- Department of Mineralogy and Crystallography
- External organisation(s)
- Almazjuvelirexport, University of Chemistry and Technology, Prague, Masaryk University, Czech Academy of Sciences, National Museum Prague, Independent researcher
- Journal
- Mineralogical Magazine
- Volume
- 78
- Pages
- 535-547
- No. of pages
- 13
- ISSN
- 0026-461X
- DOI
- https://doi.org/10.1180/minmag.2014.078.3.04
- Publication date
- 06-2014
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 104026 Spectroscopy, 105116 Mineralogy, 105113 Crystallography
- Keywords
- ASJC Scopus subject areas
- Geochemistry and Petrology
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/hydroniumjarosite-h3o-fe3so42oh6-from-cerros-pintados-chile(8e41ad61-7d4f-40e0-ba9f-d097dc27071e).html