Results 181 to 190 of about 3,477 (195)

Pressure-induced phase transition in synthetic trioctahedral Rb-mica

Physics and Chemistry of Minerals, 2003
The crystal structure of a synthetic Rb analog of tetra-ferri-annite (Rb–TFA) 1M with the composition Rb0.99Fe2+ 3.03(Fe3+ 1.04 Si2.96)O10.0(OH)2.0 was determined by the single-crystal X-ray diffraction method. The structure is homooctahedral (space group C2/m) with M1 and M2 occupied by divalent iron.
COMODI, Paola, Drabek M., Montagnoli M., Rieder M., Weiss Z., ZANAZZI, Pier Francesco   +5 more
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Quadrupole Splitting Distribution of Fe2+ in Synthetic Trioctahedral Micas

Hyperfine Interactions, 2002
About 80 different synthetic trioctahedral micas {K}[Fe2+ 3−x Me x ]〈Si,Al,Fe〉4O10(OH)2 with Me = Ni2+, Mg2+, Co2+, Al3+ and Fe3+ have been synthesized by hydrothermal methods and subsequently investigated by 57Fe Mossbauer spectroscopy. Mossbauer spectra were refined in terms of a quadrupole splitting distribution (QSD) with at least 2 components for ...
G. J. Redhammer, G. Amthauer, W. Lottermoser, G. Roth   +3 more
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Lithium in the interlayer space of synthetic trioctahedral micas

Chemical Geology, 1983
Abstract This paper gives several new and strong arguments in favour of the possibility of fixation of anhydrous lithium in the interlayer space of trioctahedral potassium micas. From the chemical viewpoint Li+ can replace K+, but is located out of the alkaline cation site; it enters pseudo-octahedral cavities limited by the triangular bases of two ...
J.-L. Robert, M. Volfinger, J.-N. Barrandon, M. Basutçu   +3 more
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Infrared Evidence of Dioctahedral-Trioctahedral Site Occupancy in Palygorskite

Clays and Clay Minerals, 2002
AbstractA Mg-rich palygorskite sample from phosphorite deposits of Ganntour (Morocco) with the structural formula Si8(Mg2.6Al1.19Fe0.33III□0.88)Ca0.056Na0.024K0.104O20(OH)2(OH2)4⋅4H2O, was studied by FTIR spectroscopy. In both OH-stretching and OH-bending regions, there is evidence of dioctahedral Al2□OH, AlFe□OH and trioctahedral Mg3OH features ...
A. Chahi, S. Petit, A. Decarreau
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Topotactic route to synthesis of novel hydroxylated phases: I. Trioctahedral Micas

Clay Minerals, 1986
AbstractK-depleted phlogopite mica was used as a topotactic precursor and treated with alkali (Li+, K+, , Rb+, Cs+), alkaline-earth (Mg2+, Ca2+, Sr2+, Ba2+) and trivalent (Al3+) cations under hydrothermal conditions of 200°C and 30 MPa pressure. K-, NH4-, Rb- and Cs-aluminosilicate micas were synthesised at 200°C in one day.
S. Komarneni, R. Roy
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Salt Displacement and Titration of AlCl3‐Treated Trioctahedral Vermiculites

Soil Science Society of America Journal, 1967
Abstract Freshly prepared and 45‐day‐aged Al‐saturated trioctahedral vermiculites from Libby, Montana, and northeastern Transvaal, South Africa, were: (i) leached with 1 N and 0.05 N solutions of NaCl, KCl, and CaCl
Malek T. Kaddah, N. T. Coleman
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Hydrothermal synthesis of a Cs ferruginous trioctahedral mica

1998
Hydrothermal experiments aimed at the synthesis of trioctahedral ferruginous Cs micas were carried out at 100 MPa and a constant temperature in the range 500-710 degrees C or in a temperature gradient. Starting mixes consisted of SiO(2), Fe(2)O(3), Al(2)O(3), Cs(2)CO(3); there was excess water in all runs, and in some runs also an excess of CsOH or Cs ...
DRABEK, M., RIEDER, M., VITI, C., WEISS, Z., FRYDA, J.   +4 more
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Crystal Chemical Models on Trioctahedral and Dioctahedral Micas

2005
nd
BRIGATTI, Maria Franca, Guggenheim S., LAURORA, Angela, MALFERRARI, Daniele, Poppi M., POPPI, Luciano   +5 more
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Crystal chemistry of Ba-rich trioctahedral micas-1M.

1993
Ten single-crystal X-ray structure refinements of igneous and metamorphic Ba-bearing micas were determined to define the exchange vectors required to compensate for the excess in positive layer charge caused by [XII]Ba2+ for [XII]K+ substitution. The determined exchange vector is BaAlK−1Si−1.
BRIGATTI, Maria Franca, POPPI, Luciano
openaire   +1 more source

Trioctahedral micas: relationships between crystal chemistry and magnetic behavior

2010
This study is aimed at verifying the factors affecting magneticsusceptibility χ variation in micas in relation to: I) Fe content;ii) Fe2+/Fe3+ ratio; iii) occurrence of Fe in tetrahedral andoctahedral sites, outlining possible ordering effects.Other aspects considered in our study will involve: i)eventually observed variation in magnetic properties ...
AFFRONTE, Marco, BRIGATTI, Maria Franca, MALFERRARI, Daniele, Marcelli A., Pini S.   +4 more
openaire   +1 more source