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Electron Microscopic Investigations of Iron Oxyhydroxides and Accompanying Phases in Lateritic Iron-crust Pisolites
Goethite Hematite Iron Kaolinite Laterite Lattice fringe image Pisolite Transmission electron microscopy
2011/11/25
Abstract: Pisolites from an iron crust in western Senegal were studied by conventional and high-resolution electron microscopy to determine their internal structure and the genetic processes that led ...
Supergene Vermiculitization of a Magnesian Chlorite: Iron and Magnesium Removal Processes
Chlorite Infrared spectroscopy Interstratified chlorite/vermiculite Iron Mossbauer spectroscopy Vermiculite Weathering
2012/1/12
An X-ray powder diffraction study of a vermiculitized chlorite in an amphibole schist near Limoges, France, shows the following weathering sequence: chlorite → ordered interstratified chlorite/vermicu...
Magnetic Ordering at 4.2 and 1.3 K in Nontronites of Different Iron Contents: A 57Fe M鰏sbauer Spectroscopic Study
Interlayer site Iron Magnetic ordering Mossbauer spectroscopy Nontronite Octahedral site Tetrahedral site
2012/1/11
The 57Fe M鰏sbauer spectra of six nontronite samples were measured at appropriate temperatures of 4.2 and 1.3 K. Three of the nontronites gave a complex magnetic hyperfine spectrum showing magnetic ord...
Mossbauer Spectroscopic Study of the Iron Mineralogy of Post-Glacial Marine Clays
Hematite Iron Magnetite Mossbauer spectroscopy Quick clay Smectite Yield strength
2012/1/12
Three post-glacial marine clays from eastern Canada and one marine clay from Japan have been studied by M鰏sbauer spectroscopy to ascertain their iron mineralogy. Small amounts of hematite (in two samp...
Role of Structural Hydrogen in the Reduction and Reoxidation of Iron in Nontronite
Hydrogen Nontronite Oxidation Reduction Structural sites Tritium
2012/2/2
The effects of reduction and reoxidation of octahedral Fe3+ on the exchange of structural hydrogen in nontronite were determined using tritium (3H) as a label element. The uptake of H from the surroun...
Iron Sites in Nontronite and the Effect of Interlayer Cations From Mossbauer Spectra
Interlayer cation Iron Mossbauer spectroscopy Nontronite Octahedral site
2011/11/25
Abstract: The 57Fe Mössbauer spectra of untreated, Ca- and K-saturated nontronite from Garfield, Washington, were measured. The spectrum of the untreated sample was computer-fitted to 8 peaks def...
Effect of Clay Mineralogy and Aluminum and Iron Oxides on the Hydraulic Conductivity of Clay-Sand Mixtures
Aluminum oxide Exchangeable sodium percentage Hydraulic conductivity Illite Iron oxide Montmorillonite Salinity Sand
2012/2/2
Changes in hydraulic conductivity and clay dispersivity of clay-sand mixtures (four reference smectites and Fithian illite) as a function of concentration (0.01 M Cl− and distilled water) and so...
Structural Studies of Nontronites with Different Iron Contents by 57Fe Mossbauer Spectroscopy
Interlayer cation Iron Mossbauer spectroscopy Nontronite Structural sites
2012/2/1
The 57Fe M鰏sbauer spectra of a series of untreated and Ca-saturated nontronites showed a predominant Fe3+ resonance which was computer-fitted with two Fe3+ doublets defining iron in non-equivalent cis...
Crystallization of Iron Oxides on Calcite Surfaces in Static Systems
Calcite Crystallization Goethite Iron oxide Lepidocrocite Synthesis
2012/1/13
Iron salts react readily with calcite in oxidizing calcareous environments to produce solid phase Fe-oxides. These reactions represent important processes in aqueous, geologic, and pedogenic environme...
Interactions of Polycations of Aluminum and Iron with Clays
Aluminum Electrophoresis Intercalation Iron Kaolinite Montmorillonite Polycations Surface charge
2011/11/25
Abstract: Polycations of limited molecular size were prepared from 0.1 M solutions of Fe(III)(NO3)3 and Al(NO3)3 by ultrafiltration. Various amounts of the polycations were added to Na-kaolinite, Na-m...
The Influence of Aluminum on Iron Oxides. VIII. Unit-Cell Dimensions of Al-Substituted Goethites and Estimation of Al From Them
Aluminum Goethite Iron Unit-cell dimensions X-ray powder diffraction
2011/11/25
Abstract: The unit-cell dimensions of synthetic, Al-substituted goethites showed that the c dimension is a linear function of Al substitution in the range 0?3 mole % Al, but that the a dimension is va...
Effects of Oxidation State of Octahedral Iron on Clay Swelling
Iron Nontronite Oxidation Reduction Smectite Swelling
2012/2/6
Three montmorillonites and a nontronite were reduced by sodium dithionite to obtain different amounts of Fe2+ in their octahedral sites. The mass ratio of water to clay, mw/mc, was determined as a fun...
Effects of Reduction and Reoxidation of Structural Iron on the Surface Charge and Dissolution of Dioctahedral Smectites
Dissolution Iron Nontronite Oxidation Reduction Smectite Surface area
2012/2/6
The effect of Fe oxidation state on the surface charge (CEC) and solubility of smectites were studied using the <2-祄, Na+-saturated fraction of an Upton, Wyoming; a Czechoslovakian; and a New Zealand ...
Influence of Chloride on the Formation of Iron Oxides from Fe(II) Chloride. II. Effect of [Cl] on the Formation of Lepidocrocite and its Crystallinity
Chloride Green rust Iron oxides Lepidocrocite Oxidation X-ray powder diffraction
2012/2/3
Diffractograms of lepidocrocites formed from the oxidation of Fe(II) chloride solutions at pH 7 and 25∑C showed differential line broadening with (0k0) reflections being much sharper than (hk0) or (hk...
Influence of Chloride on the Formation of Iron Oxides from Fe(II) Chloride. I. Effect of [Cl]/[Fe] on the Formation of Magnetite
Akaganeite Chloride Green rust Iron Lepidocrocite Maghemite Magnetite Synthesis
2012/2/3
The formation of fine-grained magnetite (∼0.1 µm) at pH 7 and 25°C from aeration of Fe(II) chloride solutions is presented. The magnetite converted at 105°C to maghemite with poorly develo...