New mineralogical data for khademite (orthorhombic AlSO4F·5H2O) and the story of rostite (orthorhombic AlSO4OH·5H2O) from Libušín near Kladno, the Czech Republic

Košek, Filip; Žáček, Vladimír; Škoda, Radek; Laufek, František; Jehlička, Jan

doi:10.1016/j.molstruc.2018.07.061

Cited by 4 publications

(21 citation statements)

References 16 publications

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“…Table 2 compares our results with available micro-Raman spectroscopic data collected on both khademite and its (OH)-analogue rostite. Data for the Monte Arsiccio sample are in good agreement, within experimental uncertainties, with those given by Frost et al (2015) and Košek et al (2019). On the contrary, the sample of khademite studied by Frost et al (2013b) shows a completely different Raman spectrum; this disagreement is probably due to the fact that these authors studied a specimen that had not been fullycharacterised.…”

Section: Micro-raman Spectroscopysupporting

confidence: 75%

“…Stormer et al, 1993;Raudsepp, 1995;Ottolini et al, 2000). Quantitative chemical data of khademite, including F, have been reported by Žáček and Povondra (1988), Williams and Cesbron (1983) and Košek et al (2019). Data given in Table 1, recalculated on the basis of 10 anions per formula unit (pfu), assuming the occurrence of 5 H 2 O and 1 (F+OH) pfu, in agreement with our structural data, gives the following chemical formula for khademite from the Monte Arsiccio mine: Al 0.96 S 1.02 O 4 [F 0.84 (OH) 0.16 ] Σ1.00 ⋅5H 2 O.…”

Section: Chemical Datamentioning

confidence: 85%

“…The maxima of the broad Raman bands are in agreement with such an interpretation. Košek et al (2019) interpreted the Raman band at 3404 cm -1 as due to the hydroxyl stretching mode. However, this is not proved by structural data and disagrees with previous data reported for sulfate minerals.…”

Section: Micro-raman Spectroscopymentioning

confidence: 99%

“…Brese and O'Keeffe (1991) were used for Al-O, Al-F and S-O bonds; simplified bond-valences, agreeing with Brown and Altermatt (1985), are reported for H bonds Can rostite be a valid mineral species? Khademite and its (OH)-analogue rostite have a troubled history, as summarised by Košek et al (2019). These authors stated that the crystal structure study of khademite performed by Bachet et al (1981) "found that the atomic positions in the structure were so small that they require the presence of fluorine, and that the presence of OH in the structure was not possible."…”

Section: Single-crystal X-ray Diffractionmentioning

confidence: 99%

“…Recently, another fluo-sulfate, khademite, was identified at the Monte Arsiccio mine. The current definition of khademite is the result of a long and debated history summarised by Košek et al (2019). As a matter of fact, a modern and full characterisation of khademite is still lacking, as Bachet et al (1981) gave no chemical analysis and no further crystal-structure refinements were reported.…”

Section: Introductionmentioning

confidence: 99%

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Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO₄)F(H₂O)₅

Mauro

Biagioni

Pasero

et al. 2020

MinMag

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Khademite, ideally Al(SO4)F(H2O)5, from the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy, has been characterised through quantitative electron microprobe analysis, micro-Raman spectroscopy and single-crystal X-ray diffraction. Khademite occurs as colourless to whitish tabular crystals, up to 5 mm. Electron microprobe analysis (in wt.%, average of 20 spot analyses) gave: SO3 35.43, Al2O3 21.27, F 6.92, H2Ocalc 39.73, sum 103.35, –O = F 2.92, total 100.43. On the basis of 10 anions per formula unit, assuming the occurrence of 5 H2O groups and 1 (F+OH) atom per formula unit, its chemical formula can be written as Al0.96S1.02O4[F0.84(OH)0.16]Σ1.00⋅5H2O. The Raman spectrum of khademite is characterised by the occurrence of vibrational modes of SO4 groups and by broad and strong bands due to the O–H stretching modes. Khademite is orthorhombic, space group Pcab, with unit-cell parameters a = 11.1713(2), b = 13.0432(3), c = 10.8815(2) Å, V = 1585.54(5) Å3 and Z = 8. The crystal structure refinement converged to R1 = 0.0293 on the basis of 2359 unique reflections with Fo > 4σ(Fo) and 152 refined parameters. The crystal structure of khademite is characterised by the alternation, along b, of two distinct kinds of {010} layers, one formed by [001] rows of isolated Al-centred octahedra, connected to each other through H bonds, and the other showing isolated SO4 groups. Along b, oxygen atoms belonging to SO4 groups act as acceptor of H bonds from H2O groups coordinating Al atoms. The new data improved the description of the H bonds in khademite and led us to discuss about the possible existence of its (OH)-analogue, rostite. In addition, Raman spectroscopic data were collected on the same crystal used for the crystal-chemical characterisation, allowing a comparison with previous results.

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Section: Micro-raman Spectroscopysupporting

confidence: 75%

Section: Chemical Datamentioning

confidence: 85%

Section: Micro-raman Spectroscopymentioning

confidence: 99%

Section: Single-crystal X-ray Diffractionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO₄)F(H₂O)₅

Mauro

Biagioni

Pasero

et al. 2020

MinMag

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Raman spectroscopy of anhydrous and hydrated aluminum sulfates: Experience from burning coal heaps

Košek

Culka

Rousaki

et al. 2022

J Raman Spectroscopy

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Hydrated aluminum‐rich sulfates belong to less widespread secondary minerals on Mars, which are probably connected with hydrothermal alterations. On Earth, such sulfates result from acidic weathering of aluminosilicates, and their formation is controlled by factors such as pH, temperature, or water activity. Physical–chemical conditions can be reconstructed if specific sulfate phases are detected, and therefore, the investigation of sulfate assemblages in high‐temperature settings is important for planetology and exobiology research. Raman spectroscopy is a powerful analytical tool for the discrimination of sulfates, and the degree of hydration, which is a sensitive marker of temperature conditions, can be tracked using this method. However, spectral similarities of sulfates and metastability and rapid transformations may hinder their correct identification. We take advantage of in situ and laboratory Raman spectroscopy to characterize uncommon anhydrous and hydrated Al‐NH4 sulfate mineralogy which forms under elevated temperature at the Anna burning coal waste dump, Alsdorf, Germany, and can be considered as analogous to fumarolic environments. We detected a suite of hydrated Al sulfates (e.g. alunogen, khademite, and tschermigite) in the medium‐temperature zones (~50°C). To minimize possible rehydration processes, we deployed two miniaturized Raman spectrometers (532 and 1064 nm) for field investigations in the high‐temperature zone (~130°C to 150°C). Mixtures of anhydrous (godovikovite and millosevichite) and hydrated phases along with intermediate phases were detected in the field as well as in the laboratory. Such observations are consistent with the premise that the degree hydration of sulfates increase with decreasing temperature. These results confirm that Raman spectroscopy is, despite several analytical challenges, capable of distinguishing Al sulfates, and their hydration states, within complex aggregates and crusts, and future applications in planetary research are promising.

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Infrared and Raman spectroscopy of tschermigite, (NH4)Al(SO4)2·12H2O

Сергеева

Zhitova

Bocharov

2019

Vibrational Spectroscopy

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New mineralogical data for khademite (orthorhombic AlSO4F·5H2O) and the story of rostite (orthorhombic AlSO4OH·5H2O) from Libušín near Kladno, the Czech Republic

Cited by 4 publications

References 16 publications

Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO₄)F(H₂O)₅

Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO₄)F(H₂O)₅

Raman spectroscopy of anhydrous and hydrated aluminum sulfates: Experience from burning coal heaps

Infrared and Raman spectroscopy of tschermigite, (NH4)Al(SO4)2·12H2O

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New mineralogical data for khademite (orthorhombic AlSO4F·5H2O) and the story of rostite (orthorhombic AlSO4OH·5H2O) from Libušín near Kladno, the Czech Republic

Cited by 4 publications

References 16 publications

Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO4)F(H2O)5

Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO4)F(H2O)5

Raman spectroscopy of anhydrous and hydrated aluminum sulfates: Experience from burning coal heaps

Infrared and Raman spectroscopy of tschermigite, (NH4)Al(SO4)2·12H2O

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Resources

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Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO₄)F(H₂O)₅

Crystal-chemistry of sulfates from the Apuan Alps, Tuscany, Italy. VIII. New data on khademite, Al(SO₄)F(H₂O)₅