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leonite

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Journal Article

Dehydration of blödite, Na 2 Mg(SO 4 ) 2 (H 2 O) 4 , and leonite, K 2 Mg(SO 4 ) 2 (H 2 O) 4 Available to Purchase

Tonči Balić-Žunić, Renie Birkedal, Anna Katerinopoulou, Paola Comodi
Published: 01 March 2016
European Journal of Mineralogy (2016) 28 (1): 33–42.
DOI: https://doi.org/10.1127/ejm/2015/0027-2487
...Tonči Balić-Žunić; Renie Birkedal; Anna Katerinopoulou; Paola Comodi Abstract The high-temperature behaviour of blödite (Na 2 Mg(SO 4 ) 2 (H 2 O) 4 ) and leonite (K 2 Mg(SO 4 ) 2 (H 2 O) 4 ) was studied by X-ray diffraction on powder samples in open capillaries and by thermo-gravimetry/calorimetry...
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View PDF for article title, Dehydration of blödite, Na 2 Mg(SO 4 ) 2 (H 2 O) 4 , and <span class="search-highlight">leonite</span>, K 2 Mg(SO 4 ) 2 (H 2 O) 4
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Journal Article

Vibrational spectroscopy of phase transitions in leonite-type minerals Available to Purchase

Birgit HERTWECK, Eugen LIBOWITZKY
Published: 01 November 2002
European Journal of Mineralogy (2002) 14 (6): 1009–1017.
DOI: https://doi.org/10.1127/0935-1221/2002/0014-1009
...Birgit HERTWECK; Eugen LIBOWITZKY Abstract Infrared (IR) and Raman spectra of leonite-type minerals, K 2 Me(SO 4 ) 2 .4H 2 O (Me = Mg, Mn, Fe), confirm a succession of structural phase transitions between 277 and 120 K. Because the orientation and dynamic behaviour of the sulphate tetrahedra...
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View PDF for article title, Vibrational spectroscopy of phase transitions in <span class="search-highlight">leonite</span>-type minerals
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Journal Article

The crystal structures of the low-temperature phases of leonite-type compounds, K 2 Me(SO 4 ) 2 ·4H 2 O (Me 2+ = Mg, Mn, Fe) Available to Purchase

Birgit Hertweck, Gerald Giester, Eugen Libowitzky
Published: 01 October 2001
American Mineralogist (2001) 86 (10): 1282–1292.
DOI: https://doi.org/10.2138/am-2001-1016
...Birgit Hertweck; Gerald Giester; Eugen Libowitzky Abstract Recent optical and differential scanning calorimetry measurements indicate phase transitions in leonite-type compounds at low temperatures. The crystal structures of these phases, i.e., leonite, K 2 Mg(SO 4 ) 2 ·4H 2 O, “Mn-leonite”, K 2 Mn...
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View PDF for article title, The crystal structures of the low-temperature phases of <span class="search-highlight">leonite</span>-type compounds, K 2 Me(SO 4 ) 2 ·4H 2 O (Me 2+ = Mg, Mn, Fe)
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Journal Article

Leonite [K 2 Mg(SO 4 ) 2 · 4 H 2 O], konyaite [Na 2 Mg(SO 4 ) 2 · 5 H 2 O] and syngenite [K 2 Ca(SO 4 ) 2 ·H 2 O] from Tausoare Cave, Rodnei Mts, Romania Available to Purchase

B. P. Onac, W. B. White, I. Viehmann
Published: 01 February 2001
Mineralogical Magazine (2001) 65 (1): 103–109.
... analysis, scanning electron microscopy and electron microprobe. Beside thenardite (dehydration product of mirabilite) we also identified three sulphate minerals: leonite [K 2 Mg(SO 4 ) 2 ·4H 2 O], syngenite [K 2 Ca(SO 4 ) 2 ·H 2 O] and konyaite [Na 2 Mg(SO 4 ) 2 ·5H 2 O]. Of these, leonite and konyaite...
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View PDF for article title, <span class="search-highlight">Leonite</span> [K 2 Mg(SO 4 ) 2 · 4 H 2 O], konyaite [Na 2 Mg(SO 4 ) 2 · 5 H 2 O] and syngenite [K 2 Ca(SO 4 ) 2 ·H 2 O] from Tausoare Cave, Rodnei Mts, Romania
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Journal Article

Mereiterite, K 2 Fe[SO 4 ] 2 .4H 2 O, a new leonite-type mineral from the Lavrion mining district, Greece Available to Purchase

Gerald Giester, Branko Rieck
Published: 01 June 1995
European Journal of Mineralogy (1995) 7 (3): 559–566.
View PDF for article title, Mereiterite, K 2 Fe[SO 4 ] 2 .4H 2 O, a new <span class="search-highlight">leonite</span>-type mineral from the Lavrion mining district, Greece
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FTIR absorption spectra of the sulphate stretching modes in (a) leonite, (b) “Mn-leonite”, and (c) mereiterite. Dashed lines indicate the appearance and disappearance of vibrational modes at the I2/a ⟷ P21/a phase transitions in leonite and “Mn-leonite”. Temperature steps of the measurements and offset of the spectra as in Fig. 4.

FTIR absorption spectra of the sulphate stretching modes in (a) leonite, (b... Available to Purchase

Published: 01 November 2002
Fig. 5. FTIR absorption spectra of the sulphate stretching modes in (a) leonite, (b) “Mn-leonite”, and (c) mereiterite. Dashed lines indicate the appearance and disappearance of vibrational modes at the I 2/ a ⟷ P 2 1 / a phase transitions in leonite and “Mn-leonite”. Temperature steps
Image
FTIR absorption spectra of the O-H stretching modes in (a) leonite, (b) “Mn-leonite”, and (c) mereiterite. Dashed lines indicate the appearance of additional vibrational modes at the I2/a ⟷ P21/a phase transitions in leonite and “Mn-leonite”. Temperature steps of the measurements and offset of the spectra as in Fig. 4.

FTIR absorption spectra of the O-H stretching modes in (a) leonite, (b) “Mn... Available to Purchase

Published: 01 November 2002
Fig. 6. FTIR absorption spectra of the O-H stretching modes in (a) leonite, (b) “Mn-leonite”, and (c) mereiterite. Dashed lines indicate the appearance of additional vibrational modes at the I 2/ a ⟷ P 2 1 / a phase transitions in leonite and “Mn-leonite”. Temperature steps
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Full Width Half Maximum and peak centre of the ν−1 sulphate modes in Raman spectra as a function of temperature in (a) leonite, (b) “Mn-leonite”, and (c) mereiterite. Vertical dashed lines indicate the transition temperatures of the C2/m ⟷ I2/a ⟷ P21/a phase transitions for leonite and “Mn-leonite”, and the transition temperatures of the C2/m ⟷ P21/a phase transition for mereiterite. The baseline (solid line) to determine the excess FWHM of the ν1 mode in leonite (cf. Fig. 9) was fitted using the saturation function.

Full Width Half Maximum and peak centre of the ν −1 sulphate modes in Ra... Available to Purchase

Published: 01 November 2002
Fig. 3. Full Width Half Maximum and peak centre of the ν −1 sulphate modes in Raman spectra as a function of temperature in (a) leonite, (b) “Mn-leonite”, and (c) mereiterite. Vertical dashed lines indicate the transition temperatures of the C 2/ m ⟷ I 2/ a ⟷ P 2 1 / a phase transitions
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The crystal structures of the leonite-type compounds in a projection along [001]. Approximately half of the unit cell is plotted along [100]. Groups of MeO6 octahedra with two sulfate tetrahedra are oriented nearly parallel to [100]. They are interconnected by K atoms (large spheres) and H2O molecules (H atoms as small spheres). Dashed lines represent H···O distances between 1.7 and 2.5 Å. (a) C2/m crystal structure of leonite, “Mn-leonite” and mereiterite at 293 K. The ordered sulfate groups are plotted as tetrahedra, the disordered sulfate groups are plotted as central atom–ligand bond system with split oxygen atoms. (b) I2/a crystal structure of leonite at 170 K (“Mn-leonite” at 185 K). Groups of one MeO6 octahedron with two sulfate tetrahedra are tilted and deviate from the (010) plane. The deviation of the Sd tetrahedron from the (010) plane alternates along [001]. (c) P21/a crystal structure of leonite at 100 K (“Mn-leonite” at 110 K, mereiterite at 185 K).

The crystal structures of the leonite-type compounds in a projection along ... Available to Purchase

Published: 01 October 2001
F igure 1. The crystal structures of the leonite-type compounds in a projection along [001]. Approximately half of the unit cell is plotted along [100]. Groups of MeO 6 octahedra with two sulfate tetrahedra are oriented nearly parallel to [100]. They are interconnected by K atoms (large
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Examples of autocorrelation analyses of Raman and FTIR absorption spectra of leonite-type compounds. Vertical dashed lines indicate the transition temperatures of the C2/m ⟷ I2/a ⟷ P21/a phase transitions for leonite and “Mn-leonite”, and the transition temperature of the C2/m ⟷ P21/a phase transition for mereiterite. Variation of Δ Corr is plotted as a function of temperature calculated from (a) IR spectra of mereiterite in the range between 900 and 1300 cm−1, (b) Raman spectra of mereiterite in the range between 1095.3 and 1159.8 cm−1 shift, (c) IR spectra of leonite in the range between 900 and 1300 cm−1, (d) Raman spectra of “Mn-leonite” in the range between 1053.3 and 1153.2 cm−1 shift. Baselines (solid lines) to determine δ ΔCorr (cf. Fig. 9) were fitted using the saturation function.

Examples of autocorrelation analyses of Raman and FTIR absorption spectra o... Available to Purchase

Published: 01 November 2002
Fig. 8. Examples of autocorrelation analyses of Raman and FTIR absorption spectra of leonite-type compounds. Vertical dashed lines indicate the transition temperatures of the C 2/ m ⟷ I 2/ a ⟷ P 2 1 / a phase transitions for leonite and “Mn-leonite”, and the transition temperature of the C
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Raman spectra of the sulphate ν3 and ν4 modes in leonite-type compounds. Vertical lines (as a guide for the eye) indicate the appearance or disappearance, respectively, of vibrational modes at the I2/a ⟷ P21/a phase transitions for leonite and “Mn-leonite”. (a) Raman spectra of leonite in the temperature range between 303 and 78 K measured in temperature steps of 10 K between 303 and 83 K. Phase transitions at 269 and 120 K. (b) Raman spectra of “Mn-leonite” in the temperature range between 295 and 140 K. Phase transitions at 205 and 169 K. Temperature intervals as indicated in Fig. 3. (c) Raman spectra of mereiterite in the temperature range between 310 and 160 K measured in temperature steps of 5 K (310-285 K), of 2 K (285-279 K), of 1 K (279-270 K), of 2 K (270-260 K), of 5 K (260-220 K), and of 10 K (220-160 K). Phase transition at 277 K. The intensity-normalised spectra are displayed with an offset of 5000 counts.

Raman spectra of the sulphate ν 3 and ν 4 modes in leonite-type compo... Available to Purchase

Published: 01 November 2002
Fig. 2. Raman spectra of the sulphate ν 3 and ν 4 modes in leonite-type compounds. Vertical lines (as a guide for the eye) indicate the appearance or disappearance, respectively, of vibrational modes at the I 2/ a ⟷ P 2 1 / a phase transitions for leonite and “Mn-leonite”. (a) Raman
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Details of the hydrogen bonds surrounding the tetrahedra in the crystal structures of leonite and “Mn-leonite”. (a) So tetrahedron of the I2/a crystal structure (b) Sd tetrahedron of the I2/a (left) and C2/m (right) crystal structures.

Details of the hydrogen bonds surrounding the tetrahedra in the crystal str... Available to Purchase

Published: 01 October 2001
F igure 2. Details of the hydrogen bonds surrounding the tetrahedra in the crystal structures of leonite and “Mn-leonite”. ( a ) S o tetrahedron of the I 2/ a crystal structure ( b ) S d tetrahedron of the I 2/ a (left) and C 2/ m (right) crystal structures.
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Crystal structures of (a) blödite and (b) leonite. Sulphate groups are coloured grey, MgO6 octahedra orange. Hydrogen atoms are represented black, Na atoms yellow and K atoms red. For the sake of clarity, for leonite an ordered low-temperature polymorph (Hertweck et al., 2001) is shown.

Crystal structures of (a) blödite and (b) leonite. Sulphate groups are colo... Available to Purchase

Published: 01 March 2016
Fig. 1 Crystal structures of (a) blödite and (b) leonite. Sulphate groups are coloured grey, MgO 6 octahedra orange. Hydrogen atoms are represented black, Na atoms yellow and K atoms red. For the sake of clarity, for leonite an ordered low-temperature polymorph ( Hertweck et al. , 2001
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TGA curve, the first derivative of the TGA curve, and the DSC curve for leonite, K2Mg(SO4)2(H2O)4. At the bottom are indicated the results of the X-ray diffraction analysis. The red line marks the presence of leonite and kainite whereas the blue line marks the presence of langbeinite, arcanite and sylvine.

TGA curve, the first derivative of the TGA curve, and the DSC curve for leo... Available to Purchase

Published: 01 March 2016
Fig. 5 TGA curve, the first derivative of the TGA curve, and the DSC curve for leonite, K 2 Mg(SO 4 ) 2 (H 2 O) 4 . At the bottom are indicated the results of the X-ray diffraction analysis. The red line marks the presence of leonite and kainite whereas the blue line marks the presence
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Schematic picture of the phase transitions of the leonite-type compounds. The room temperature phases have a crystal structure with space group C2/m, the intermediate phases have a crystal structure with space group I2/a and the low-temperature phases have a crystal structure with space group P21/a. The crystal structures are plotted without K ions and H2O molecules. Full arrows show supergroup/subgroup relationships between the room temperature structure and both low-temperature derivatives, the small arrows show the succession of the structural changes in leonite and “Mn-leonite.” Groups of octahedra with two tetrahedra form layers parallel to (001). Layers with ordered tetrahedra are indicated as A, layers with disordered tetrahedra are indicated as B.

Schematic picture of the phase transitions of the leonite-type compounds. T... Available to Purchase

Published: 01 October 2001
F igure 4. Schematic picture of the phase transitions of the leonite-type compounds. The room temperature phases have a crystal structure with space group C 2/ m , the intermediate phases have a crystal structure with space group I 2/ a and the low-temperature phases have a crystal structure
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The thermal evolution of (δ ΔCorr)2 and (δFWHM)2 for (a) autocorrelated IR spectra of mereiterite in the range between 900 and 1300 cm−1, (b) autocorrelated Raman spectra of mereiterite in the range between 1095.3 and 1159.8 cm−1 shift, (c) autocorrelated IR spectra of leonite in the range between 900 and 1300 cm−1, (d) ν1 Raman stretching mode of leonite. Errors in the order parameters are within the size of the plotted data points.

The thermal evolution of (δ ΔCorr) 2 and (δFWHM) 2 for (a) autocorrelated... Available to Purchase

Published: 01 November 2002
Fig. 9. The thermal evolution of (δ ΔCorr) 2 and (δFWHM) 2 for (a) autocorrelated IR spectra of mereiterite in the range between 900 and 1300 cm −1 , (b) autocorrelated Raman spectra of mereiterite in the range between 1095.3 and 1159.8 cm −1 shift, (c) autocorrelated IR spectra of leonite
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FTIR absorption spectra of the sulphate bending modes of the leonite-type compounds in the indicated temperature ranges. Dashed lines (as a guide for the eye) indicate the appearance and disappearance of vibrational modes at the I2/a ⟷ P21/a phase transitions in leonite. (a) Spectra of leonite are measured in temperature steps of 5 K (300-280 K), of 2 K (280-276 K), of 1 K (276-264 K), of 2 K (264-250 K), of 5 K (250-130 K), of 2 K (130-120 K), and of 5 K (120-80 K). (b) Spectra of “Mn-leonite” are measured in temperature steps of 5 K (295-215 K), of 2 K (212-206 K), of 1 K (206-198 K), of 2 K (198-190 K), of 5 K (190-180 K), of 2 K (177-173 K), of 1 K (173-170 K), of 2 K (170-168 K), of 5 K (165-120 K), and of 10 K (120-90 K). (c) Spectra of mereiterite are measured in temperature steps of 5 K (310-285 K), of 2 K (285-279 K), of 1 K (279-272 K), of 2 K (272-250 K), of 5 K (250-210 K), and of 10 K (210-140 K). Spectra are displayed with an offset of 0.03 in absorbance units.

FTIR absorption spectra of the sulphate bending modes of the leonite-type c... Available to Purchase

Published: 01 November 2002
Fig. 4. FTIR absorption spectra of the sulphate bending modes of the leonite-type compounds in the indicated temperature ranges. Dashed lines (as a guide for the eye) indicate the appearance and disappearance of vibrational modes at the I 2/ a ⟷ P 2 1 / a phase transitions in leonite
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Platy crystal of konyaite on matrix of leonite and mirabilite.

Platy crystal of konyaite on matrix of leonite and mirabilite. Available to Purchase

Published: 01 February 2001
F ig . 3. Platy crystal of konyaite on matrix of leonite and mirabilite.
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Relative changes of the crystal lattice parameters of leonite (black) and kainite (red) with temperature. The monoclinic angles show a negligible change and are omitted.

Relative changes of the crystal lattice parameters of leonite (black) and k... Available to Purchase

Published: 01 March 2016
Fig. 6 Relative changes of the crystal lattice parameters of leonite (black) and kainite (red) with temperature. The monoclinic angles show a negligible change and are omitted.
Journal Article

Cationic Exchange between Montmorillonite and Pore Solution Salts in Hydrothermal Clays from Steam Hydrotherms of the Mutnovsky Geothermal Field Available to Purchase

A.V. Sergeeva, T.P. Tikhonov, A.A. Avilova, M.A. Nazarova, O.A. Zoben’ko, E.V. Kartasheva, A.A. Kuzmina, A.V. Gladyshkina
Published: 01 December 2024
Russ. Geol. Geophys. (2024) 65 (12): 1468–1484.
DOI: https://doi.org/10.2113/RGG20244750
... is subjected to degradation when they dry out. Crystallization of salts from pore solutions in the near-surface horizons of the studied thermal fields can be exemplified by szomolnokite FeSO 4 ‧H 2 O, metavoltine K 2 Na 6 Fe 2+ Fe 3+ 6 O 2 (SO 4 ) 12 ·18H 2 O, leonite K 2 Mg(SO 4 ) 2 ‧2H 2 O, polyhalite K 2 Ca...
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View PDF for article title, Cationic Exchange between Montmorillonite and Pore Solution Salts in Hydrothermal Clays from Steam Hydrotherms of the Mutnovsky Geothermal Field
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