Decomposition reactions of magnesium sulfate hydrates and phase equilibria in the MgSO4–H2O and Na+–Mg2+–Cl−–SO42−–H2O systems with implications for Mars

Steiger, Michael; Linnow, Kirsten; Ehrhardt, D.; Rohde, Mandy

doi:10.1016/j.gca.2011.03.038

Cited by 91 publications

(107 citation statements)

References 81 publications

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“…1. As concluded by Grevel and Majzlan (2009), starkeyite is metastable with respect to kieserite formation, but kieserite formation is known to be very sluggish under typical dehydration conditions (Steiger et al, 2011). Therefore, Fig.…”

Section: Introductionmentioning

confidence: 91%

“…in a drying cabinet (4 days) at about 320 K (Steiger et al, 2011). After verification by X-ray powder diffraction (XRD), the powdered material was kept in a closed vial in the drying cabinet before it was sent to Bochum by regular mail.…”

Section: Starkeyitementioning

confidence: 99%

“…About 20 mg of the powdered sample was sealed in an Al pan so that the powder was compressed into an *1 mm thick layer (Dachs and Bertoldi, 2005 Linke (1965). Small symbols represent new measurements of equilibrium relative humidities for several hydration-dehydration equilibria in the MgSO 4 -H 2 O system (Steiger et al, 2011). Only data points which were used by Steiger et al (2011) to derive their final phase diagram are shown.…”

Section: Low-temperature Heat Capacity Measurementsmentioning

confidence: 99%

“…Additionally, the enthalpy of formation of the trihydrate (MgSO 4 $3H 2 O) was measured. Steiger et al (2011) reported new measurements of equilibrium relative humidities for several stable and metastable hydration-dehydration equilibria in the MgSO 4 -H 2 O system (see Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

et al. 2012

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The enthalpies of formation of synthetic MgSO 4 $4H 2 O (starkeyite) and MgSO 4 $3H 2 O were obtained by solution calorimetry at T = 298.15 K. The resulting enthalpies of formation from the elements areThe standard entropy of starkeyite was derived from low-temperature heat capacity measurements acquired with a physical property measurement system (PPMS) in the temperature range 5 K < T < 300 K:Additionally, differential scanning calorimetry (DSC) measurements with a Perkin Elmer Diamond DSC in the temperature range 270 K < T < 300 K were performed to check the reproducibility of the PPMS measurements around ambient temperature.The experimental C p data of starkeyite between 229 and 303 K were fitted with a Maier-Kelley polynomial, yielding C p (T) = 107.925 + 0.5532$T -1048894$T -2 . The hydration state of all Mg sulfate hydrates changes in response to local temperature and humidity conditions. Based on recently reported equilibrium relative humidities and the new standard properties described above, the internally consistent thermodynamic database for the MgSO 4 $nH 2 O system was refined by a mathematical programming (MAP) analysis.As can be seen from the resulting phase diagrams, starkeyite is metastable in the entire T-%RH range. Due to kinetic limitations of kieserite formation, metastable occurrence of starkeyite might be possible under martian conditions.

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Section: Introductionmentioning

confidence: 91%

Section: Starkeyitementioning

confidence: 99%

Section: Low-temperature Heat Capacity Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

et al. 2012

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“…Some of the sulfate-rich deposits observed on Mars (Wang et al 2006;Steiger et al 2011) have been proposed to be evaporite beds caused by deposition from arid saline lakes, similar to Searles Lake (Barbieri and Stivaletta 2011). Hydrated salts with similar ionic constituents are thought to dominate the mantles of the icy moons of the outer planets (Chio et al 2004;Brand et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic and X-ray diffraction investigation of the behavior of hanksite and tychite at high pressures, and a model for the compressibility of sulfate minerals

Palaich

Manning

Schauble

et al. 2013

American Mineralogist

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The rare evaporite minerals hanksite, Na 22 K(SO 4 ) 9 (CO 3 ) 2 Cl, and tychite, Na 6 Mg 2 (CO 3 ) 4 (SO 4 ), are excellent case studies for the high-pressure behavior of ionic groups since their structures combine ionic complexity and high symmetry (hexagonal P6 3 /m and cubic Fd3, respectively). Here we investigate the structure and compressibility of hanksite up to 20 GPa in the diamond-anvil cell using Raman spectroscopy and X-ray diffraction and of tychite up to 17 GPa in the diamond cell using X-ray diffraction and first-principles modeling. At ambient pressure, the Raman spectrum of hanksite has a single sulfate ν 1 frequency at 992 cm -1 with a lower-frequency shoulder. As pressure is increased, this mode splits into two distinct peaks, which arise from two distinct local environments for the sulfate tetrahedra within the hanksite structure. Below 10 GPa, the mode Grüneisen parameter of the dominant sulfate ν 1 frequency is 0.27(1); the mode Grüneisen parameter of the lower frequency shoulder is 0.199(7). X-ray diffraction data of hanksite indicate a 5% volume drop between 8-10 GPa with no apparent change of symmetry. A Birch-Murnaghan fit to the data below 8 GPa yields an isothermal bulk modulus of 66(1) GPa for hanksite and 85(1) GPa for tychite, with K′ fixed at 4.

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Sulfates hydrating bulk soil in the Martian low and middle latitudes

Karunatillake

Wray

Gasnault

et al. 2014

Geophysical Research Letters

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The evidence for sulfate-bearing strata, across Late-Noachian to Amazonian eons, suggests a central role for sulfates in acidity and salinity of Martian paleofluids and the planet's habitability. However, details remain unclear owing to shallow sampling and the limited ability of visible/near-infrared spectroscopy to distinguish among some sulfates. Using chemical data from the Mars Odyssey gamma ray spectrometer, including the sulfur map of Mars, we confirm the possibility of hydrous sulfates acting as key hydrates throughout the southern midlatitudinal soil at decimeter depths. An H 2 O:S molar ratio between 2.4 and 4.0 for 80% of the midlatitudes is also consistent with hydrous sulfate phases, including the many Fe sulfates hydrated in this range or mixtures of Ca and Mg sulfates. Nevertheless, hydrous Fe sulfates could explain our observations in a simpler manner relative to Ca/Mg mixtures. Furthermore, phyllosilicates, zeolites, amorphous phases, and H 2 O(s) do not seem to be strong candidates to explain the H-S variations. Consequently, we speculate that sulfates, as the primary contributor of H 2 O in bulk soil, may influence modern aqueous processes including warm-season slope lineae in the southern hemisphere.

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Decomposition reactions of magnesium sulfate hydrates and phase equilibria in the MgSO4–H2O and Na+–Mg2+–Cl−–SO42−–H2O systems with implications for Mars

Cited by 91 publications

References 81 publications

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

Spectroscopic and X-ray diffraction investigation of the behavior of hanksite and tychite at high pressures, and a model for the compressibility of sulfate minerals

Sulfates hydrating bulk soil in the Martian low and middle latitudes

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Decomposition reactions of magnesium sulfate hydrates and phase equilibria in the MgSO4–H2O and Na+–Mg2+–Cl−–SO42−–H2O systems with implications for Mars

Cited by 91 publications

References 81 publications

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO4·4H2O (Starkeyite) and MgSO4·3H2O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO4·4H2O (Starkeyite) and MgSO4·3H2O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

Spectroscopic and X-ray diffraction investigation of the behavior of hanksite and tychite at high pressures, and a model for the compressibility of sulfate minerals

Sulfates hydrating bulk soil in the Martian low and middle latitudes

Contact Info

Product

Resources

About

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates