Abstract
Published estimates for the equilibrium relative humidity (RH) at 25 °C for the reaction: bieberite (CoSO4·7H2O) = moorhouseite (CoSO4·6H2O) + H2O, range from 69.8 to 74.5%. To evaluate these data, the humidity-buffer technique was used to determine equilibrium constants for this reaction between 14 and 43 °C at 0.1 MPa. Reversals along five humidity-buffer curves yield ln K = 18.03–6509.43/T, where K is the equilibrium constant, and T is temperature in K. The derived standard Gibbs free energy of reaction is 9.43 kJ/mol, which agrees well with several previously reported values based on vaporpressure measurements. It also agrees well with values calculated from the data derived mostly from calorimetric measurements. Previous studies indicated that the temperature of the invariant point for the assemblage bieberite-moorhouseite-aqueous solution-vapor is near 44.7 °C, and our extrapolated data predict 91.1% RH at this temperature; the predicted position for the invariant point is in excellent agreement with those reported previously.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Factors in the preservation of coesite: The importance of fluid inflitration
- U-Pb SHRIMP ages recorded in the coesite-bearing zircon domains of paragneisses in the southwestern Sulu terrane, eastern China: New interpretation
- Petrogenesis of the Yangkou layered garnet-peridotite complex, Sulu UHP terrane, China
- Sodic amphibole exsolutions in garnet from garnet-peridotite, North Qaidam UHPM belt, NW China: Implications for ultradeep-origin and hydroxyl defects in mantle garnets
- Blueschists, eclogites, and decompression assemblages of the Zermatt-Saas ophiolite: High-pressure metamorphism of subducted Tethys lithosphere
- Coexisting retrograde jadeite and omphacite in a jadeite-bearing lawsonite eclogite from the Motagua Fault Zone, Guatemala
- Calibrations of modal space for metamorphism of mafic schist
- Oxygen isotope geochemistry of rocks from the Pre-Pilot Hole of the Chinese Continental Scientific Drilling Project (CCSD-PPH1)
- Subducted carbonates, metasomatism of mantle wedges, and possible connections to diamond formation: An example from California
- Hawaiian mantle xenoliths and magmas: Composition and thermal character of the lithosphere
- Trace-element distribution coefficients for pyroxenes, plagioclase, and olivine in evolved tholeiites from the 1955 eruption of Kilauea Volcano, Hawaiʼi, and petrogenesis of differentiated rift-zone lavas
- Cation ordering in synthetic low-calcium actinolite
- Acquisition and evaluation of thermodynamic data for bieberite-moorhouseite equilibria at 0.1 MPa
- PRESIDENTIAL ADDRESS TO THE MINERALOGICAL SOCIETY OF AMERICA SEATTLE, NOVEMBER 4, 2003: A mineralogical and geochemical record of atmospheric photochemistry
- Synthesis and characterization of saponite clays
- Synthesis and characterization of saponite clays: Part 2. Thermal stability
- Estimates of Ar diffusion and solubility in leucite and nepheline: Electron microprobe imaging of Ar distribution in a mineral
- Growth and dissolution kinetics at the dolomite-water interface: An in-situ scanning probe microscopy study
- Crystal chemistry of Zn-rich rhodonite (“fowlerite”)
- The origin of the green color of variscite
- HRTEM evidence for 8-reversals in the m = 17 antigorite polysome
- Origin of high-Ag fahlores from the Galena Mine, Wallace, Idaho, U.S.A.
- Stability of the MgCO3 structures under lower mantle conditions
- The 10 Å phase: Crystal structure from single-crystal X-ray data
- Letter: Unquenchable hexagonal perovskite in high-pressure polymorphs of strontium silicates
Articles in the same Issue
- Factors in the preservation of coesite: The importance of fluid inflitration
- U-Pb SHRIMP ages recorded in the coesite-bearing zircon domains of paragneisses in the southwestern Sulu terrane, eastern China: New interpretation
- Petrogenesis of the Yangkou layered garnet-peridotite complex, Sulu UHP terrane, China
- Sodic amphibole exsolutions in garnet from garnet-peridotite, North Qaidam UHPM belt, NW China: Implications for ultradeep-origin and hydroxyl defects in mantle garnets
- Blueschists, eclogites, and decompression assemblages of the Zermatt-Saas ophiolite: High-pressure metamorphism of subducted Tethys lithosphere
- Coexisting retrograde jadeite and omphacite in a jadeite-bearing lawsonite eclogite from the Motagua Fault Zone, Guatemala
- Calibrations of modal space for metamorphism of mafic schist
- Oxygen isotope geochemistry of rocks from the Pre-Pilot Hole of the Chinese Continental Scientific Drilling Project (CCSD-PPH1)
- Subducted carbonates, metasomatism of mantle wedges, and possible connections to diamond formation: An example from California
- Hawaiian mantle xenoliths and magmas: Composition and thermal character of the lithosphere
- Trace-element distribution coefficients for pyroxenes, plagioclase, and olivine in evolved tholeiites from the 1955 eruption of Kilauea Volcano, Hawaiʼi, and petrogenesis of differentiated rift-zone lavas
- Cation ordering in synthetic low-calcium actinolite
- Acquisition and evaluation of thermodynamic data for bieberite-moorhouseite equilibria at 0.1 MPa
- PRESIDENTIAL ADDRESS TO THE MINERALOGICAL SOCIETY OF AMERICA SEATTLE, NOVEMBER 4, 2003: A mineralogical and geochemical record of atmospheric photochemistry
- Synthesis and characterization of saponite clays
- Synthesis and characterization of saponite clays: Part 2. Thermal stability
- Estimates of Ar diffusion and solubility in leucite and nepheline: Electron microprobe imaging of Ar distribution in a mineral
- Growth and dissolution kinetics at the dolomite-water interface: An in-situ scanning probe microscopy study
- Crystal chemistry of Zn-rich rhodonite (“fowlerite”)
- The origin of the green color of variscite
- HRTEM evidence for 8-reversals in the m = 17 antigorite polysome
- Origin of high-Ag fahlores from the Galena Mine, Wallace, Idaho, U.S.A.
- Stability of the MgCO3 structures under lower mantle conditions
- The 10 Å phase: Crystal structure from single-crystal X-ray data
- Letter: Unquenchable hexagonal perovskite in high-pressure polymorphs of strontium silicates