Crystal chemistry of zinc incorporation in strunzite-group minerals containing zeolitic water

2017 ◽  
Vol 81 (5) ◽  
pp. 1051-1062 ◽  
Author(s):  
I. E. Grey ◽  
E. Keck ◽  
C. M. MacRae ◽  
A. M. Glenn ◽  
A. R. Kampf ◽  
...  
Keyword(s):  
Water Molecule ◽  
Comparative Study ◽  
Electron Microprobe ◽  
Interlayer Water ◽  
Compositional Zoning ◽  
Group Mineral ◽  
Zeolitic Water ◽  
Interlayer Region ◽  
Cation Substitutions ◽  
Interlayer Water Molecule

AbstractA comparative study is presented of the chemistry and crystallography of zinc-bearing strunzites from Hagendorf Süd, Bavaria, Germany and the Sitio do Castelo mine, Folgosinho, Portugal. Electron microprobe analyses of samples from the two localities show quite different cation substitutions. The Hagendorf Süd mineral is a Zn-bearing ferristrunzite, with compositional zoning due to Zn2+ replacing predominantly Fe3+ as well as minor Mn2+, whereas the Portugese mineral is a Zn-bearing strunzite, in which Zn2+ replaces Mn2+, with minor replacement of Fe3+ by Mn3+. Zincostrunzite, with dominant Zn in the interlayer octahedrally coordinated site, is a new strunzite-group mineral that has been characterized at both locations. Analysis of single-crystal synchrotron data for zinc-bearing ferristrunzite and zincostrunzite crystals from Hagendorf Süd show that the structures of both minerals contain zeolitic water in the interlayer region. The formula for strunzite-group minerals containing the zeolitic water is MFe23+(PO4)2(OH)2·6.5H2O, M=Fe, Mn, Zn. This formulation agrees with that found for zincostrunzite from the Sitio do Castelo mine, but differs from that reported previously for strunzite, MFe2+(PO4)2(OH)2·6H2O, which has no interlayer water. Interestingly, the zincostrunzites from the two localities differ in the location of the interlayer water molecule, with a corresponding difference in the H bonding.

Structural characterization of the clay mineral illite-1M

2008 ◽  
Vol 41 (2) ◽  
pp. 402-415 ◽  
Author(s):  
Alessandro F. Gualtieri ◽  
Simone Ferrari ◽  
Matteo Leoni ◽  
Georg Grathoff ◽  
Richard Hugo ◽  
...  
Keyword(s):  
Water Molecule ◽  
Structural Characterization ◽  
Structural Model ◽  
Basic Structure ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Interlayer Water ◽  
The Status ◽  
Interlayer Water Molecule

This work reports the structural characterization of illite-1M from northern Hungary, with the first attempt to refine the structure model and locate the interlayer water molecule. Structural characterization was accomplished using state-of-the-art analytical methods available for clays. The results illustrate the status of techniques for clay structure determination, as well as providing a structural model for illite. The chemical formula for the illite-1M under investigation can be written as K0.78Ca0.02Na0.02(Mg0.34Al1.69FeIII0.02)[Si3.35Al0.65]O10(OH)2·nH2O. Structure simulations withWILDFIREyielded a model with 30% ofcis-vacant layers and an expandability percentage of 10%. The value of the percentage of expandability was confirmed withNEWMOD, with which the best simulation was obtained with 90% of di-octahedral mica with K (80% site population) in the interlayer region and 10% of expandable layers. The best structure simulation obtained withDIFFaXwas also obtained with a population of K atoms of 80%, six cells alongc(in agreement with the results of a transmission electron microscopy study) and an average dimension of the particles in theabplane of 300 nm. Besides the determination of the basic structure unit (the results are consistent with those obtained with the local information provided by a fit of the pair distribution function data) and the model of disorder, refinement withDIFFaX+allowed the calculation of a possible position for the interlayer water molecule. Although physically sound, both the observed tetrahedral layer corrugation and the location of the water molecule need further experimental evidence, because the final fit of the observed pattern is still imperfect. The reasons for this misfit are discussed.

Kummerite, Mn2+Fe3+Al(PO4)2(OH)2·8H2O, a new laueite-group mineral from the Hagendorf Süd pegmatite, Bavaria, with ordering of Al and Fe3+

2016 ◽  
Vol 80 (7) ◽  
pp. 1243-1254 ◽  
Author(s):  
I. E. Grey ◽  
E. Keck ◽  
W. G. Mumme ◽  
A. Pring ◽  
C. M. Macrae ◽  
...  
Keyword(s):  
Electron Microprobe ◽  
Empirical Formula ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
Group Mineral ◽  
X Ray ◽  
Cell Parameters ◽  
Octahedral Sites ◽  
Phosphate Mineral

AbstractKummerite, ideally Mn2+Fe3+A1(PO4)2(OH)2.8H2O, is a new secondary phosphate mineral belonging to the laueite group, from the Hagendorf-Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany. Kummerite occurs as sprays or rounded aggregates of very thin, typically deformed, amber yellow laths. Cleavage is good parallel to ﹛010﹜. The mineral is associated closely with green Zn- and Al-bearing beraunite needles. Other associated minerals are jahnsite-(CaMnMn) and Al-bearing frondelite. The calculated density of kummerite is 2.34 g cm 3. It is optically biaxial (-), α= 1.565(5), β = 1.600(5) and y = 1.630(5), with weak dispersion. Pleochroism is weak, with amber yellow tones. Electron microprobe analyses (average of 13 grains) with H2O and FeO/Fe2O3 calculated on structural grounds and normalized to 100%, gave Fe2O3 17.2, FeO 4.8, MnO 5.4, MgO 2.2, ZnO 0.5, Al2O3 9.8, P2O5 27.6, H2O 32.5, total 100 wt.%. The empirical formula, based on 3 metal apfu is (Mn2+0.37Mg0.27Zn0.03Fe2+0.33)Σ1.00(Fe3+1.06Al0. 94)Σ2.00PO4)1.91(OH)2.27(H2O)7.73. Kummerite is triclinic, P1̄, with the unit-cell parameters of a = 5.316(1) Å, b =10.620(3) Å , c = 7.118(1) Å, α = 107.33(3)°, β= 111.22(3)°, γ = 72.22(2)° and V= 348.4(2) Å3. The strongest lines in the powder X-ray diffraction pattern are [dobs in Å(I) (hkl)] 9.885 (100) (010); 6.476 (20) (001); 4.942 (30) (020); 3.988 (9) (̄110); 3.116 (18) (1̄20); 2.873 (11) (1̄21). Kummerite is isostructural with laueite, but differs in having Al and Fe3+ ordered into alternate octahedral sites in the 7.1 Å trans-connected octahedral chains.

scholarly journals Crystalline Swelling Process of Mg-Exchanged Montmorillonite: Effect of External Environmental Solicitation

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Marwa Ammar ◽  
Walid Oueslati
Keyword(s):  
Theoretical Models ◽  
Retention Mechanism ◽  
X Ray Diffraction ◽  
Interlayer Water ◽  
Hydration Properties ◽  
Crystalline Swelling ◽  
Low Charge ◽  
Interlayer Water Molecule

This work reports characterization of the possible effects that might distress the hydration properties of Mg-exchanged low-charge montmorillonite (SWy-2) when it undergoes external environmental solicitation. This perturbation was created by an alteration of relative humidity rates (i.e., RH%) over two hydration-dehydration cycles with different sequence orientations. Structural characterization is mainly based on the X-ray diffraction (XRD) profile-modeling approach achieved by comparing the “in situ” obtained experimental 00l reflections with other ones calculated from theoretical models. This method allows assessing the evolution of the interlayer water retention mechanism and the progress of diverse hydration state’s contributions versus external strain. Obtained results prove that the hydration behavior of the studied materials is strongly dependent on the RH sequence orientation which varied over cycles. The interlayer organization of Mg-exchanged montmorillonite (i.e., SWy-2-Mg) is characterized by a heterogeneous hydration behavior, which is systematically observed at different stages of both cycles. By comparing the interlayer water process evolution of Mg-exchanged montmorillonite with the observed SWy-2-Ni sample hydration behaviors, a same hysteresis thickness characterized by obvious fluctuations of interlayer water molecule abundances is observed. Nevertheless, in the case of Hg and Ba-saturated montmorillonite, the retention water process versus the applied cycles was steadier comparing with Mg ions.

Canutite, NaMn3[AsO4][AsO3(OH)]2, a new protonated alluaudite-group mineral from the Torrecillas mine, Iquique Province, Chile

2014 ◽  
Vol 78 (4) ◽  
pp. 787-795 ◽  
Author(s):  
A. R. Kampf ◽  
S. J. Mills ◽  
F. Hatert ◽  
B. P. Nash ◽  
M. Dini ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
White Light ◽  
Electron Microprobe ◽  
New Mineral ◽  
Optical Orientation ◽  
Calculated Density ◽  
Secondary Alteration ◽  
Group Mineral ◽  
X Ray ◽  
Mohs Hardness

AbstractThe new mineral canutite (IMA2013-070), NaMn3[AsO4][AsO3(OH)]2, was found at two different locations at the Torrecillas mine, Salar Grande, Iquique Province, Chile, where it occurs as a secondary alteration phase in association with anhydrite, halite, lavendulan, magnesiokoritnigite, pyrite, quartz and scorodite. Canutite is reddish brown in colour. It forms as prisms elongated on [20] and exhibiting the forms {010}, {100}, {10}, {201} and {102}, or as tablets flattened on {102} and exhibiting the forms {102} and {110}. Crystals are transparent with a vitreous lustre. The mineral has a pale tan streak, Mohs hardness of 2½, brittle tenacity, splintery fracture and two perfect cleavages, on {010} and {101}. The calculated density is 4.112 g cm−3. Optically, canutite is biaxial (+) with α = 1.712(3), β = 1.725(3) and γ = 1.756(3) (measured in white light). The measured 2V is 65.6(4)°, the dispersion is r < v (slight), the optical orientation is Z = b; X ^ a = 18° in obtuse β and pleochroism is imperceptible. The mineral is slowly soluble in cold, dilute HCl. The empirical formula (for tabular crystals from near the mineshaft), determined from electron - microprobe analyses, is (Na1.05Mn2.64Mg0.34Cu0.14Co0.03)∑4.20As3O12H1.62. Canutite is monoclinic, C2/c, a = 12.3282(4), b = 12.6039(5), c = 6.8814(5) Å, β = 113.480(8)°, V = 980.72(10) Å3 and Z = 4. The eight strongest X-ray powder diffraction lines are [dobs Å(I)(hkl)]: 6.33(34)(020), 4.12(26)(21), 3.608(29)(310,31), 3.296(57)(12), 3.150(28)(002,131), 2.819(42)(400,041,330), 2.740(100)(240,02,112) and 1.5364(31)(multiple). The structure, refined to R1 = 2.33% for 1089 Fo > 4σF reflections, shows canutite to be isostructural with protonated members of the alluaudite group.

Termination of swelling capacity of smectites by Cutrien exchange

Clay Minerals ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 411-420 ◽  
Author(s):  
S. Kaufhold ◽  
R. Dohrmann ◽  
K. Ufer ◽  
R. Kleeberg ◽  
H. Stanjek
Keyword(s):  
Water Uptake ◽  
X Ray Diffraction ◽  
Interlayer Water ◽  
Uptake Capacity ◽  
Fe Content ◽  
Water Uptake Capacity ◽  
Swelling Capacity ◽  
Adsorption Processes ◽  
Interlayer Region

AbstractThe Cu-triethylenetetramine-complex (Cutrien) is one of the commonly used index cations for CEC determination in clay science. Cutrien-exchanged smectites show basal spacings between 13.0 and 13.5 Å after correction for the Lorentz and polarization factors. The full width at half maximum (FWHM) of the d001 reflection is today related to the percentage of tetrahedral charge (beidellitic character) and/or to the Fe content of the smectites. The structural Fe content and the tetrahedral charge correlate, so their individual influence on d001 cannot be resolved. Nevertheless, the FWHM of Cutrien smectites should depend on the charge distribution rather than the Fe content.X-ray diffraction (XRD) and water uptake capacity measurements showed that the interlayer of Cutrien-exchanged smectites does not swell any more, but can take up a few water molecules. Accordingly, the water uptake capacity of the external surface area can be determined independently from the interlayer water uptake capacity. Adjusting the pH of Cutrien-bentonite dispersion to different values allows for the determination of the variable charge.In conclusion, Cutrien exchange of smectites appears to be suitable for the study of external surfaces area related phenomena (e.g. edge adsorption processes) without any influence of the interlayer region.

Iron oxidation state in garnet from a subduction setting: a micro-XANES and electron microprobe (“flank method”) comparative study

2012 ◽  
Vol 27 (10) ◽  
pp. 1725 ◽  
Author(s):  
Elisa Borfecchia ◽  
Lorenzo Mino ◽  
Diego Gianolio ◽  
Chiara Groppo ◽  
Nadia Malaspina ◽  
...  
Keyword(s):  
Comparative Study ◽  
Oxidation State ◽  
Electron Microprobe ◽  
Iron Oxidation ◽  
Iron Oxidation State ◽  
Subduction Setting ◽  
Flank Method

Electron momentum spectroscopy of the valence orbitals of the water molecule in gas and liquid phase: A comparative study

2007 ◽  
Vol 439 (1-3) ◽  
pp. 55-59 ◽  
Author(s):  
H. Hafied ◽  
A. Eschenbrenner ◽  
C. Champion ◽  
M.F. Ruiz-López ◽  
C. Dal Cappello ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Water Molecule ◽  
Comparative Study ◽  
Electron Momentum ◽  
Electron Momentum Spectroscopy

First occurrence of Mn-dominant cordierite-group mineral: electron microprobe and laser ablation ICPMS study

2019 ◽  
Vol 57 (5) ◽  
pp. 807-810
Author(s):  
Adam Szuszkiewicz ◽  
Adam Pieczka ◽  
Petr Gadas ◽  
Michaela Vašinová-Galiová ◽  
Eligiusz Szełęg ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Electron Microprobe ◽  
Group Mineral ◽  
First Occurrence

scholarly journals Movement of water in compacted bentonite and its relation with swelling pressure

2020 ◽  
Vol 57 (6) ◽  
pp. 921-932
Author(s):  
Hailong Wang ◽  
Takumi Shirakawabe ◽  
Hideo Komine ◽  
Daichi Ito ◽  
Takahiro Gotoh ◽  
...  
Keyword(s):  
Interlayer Space ◽  
Water Movement ◽  
Swelling Pressure ◽  
Testing Procedure ◽  
X Ray Diffraction ◽  
Interlayer Water ◽  
X Ray ◽  
Compacted Bentonite ◽  
Interlayer Water Molecule ◽  
Development And Evolution

A testing procedure was proposed to study water movement in compacted bentonite and the development of swelling pressure (ps) when compacted bentonite specimens were wetted. In this procedure, a multi-ring mold was introduced for ps measurements, after which the specimen was sliced for X-ray diffraction to find movement of water in the interlayer space of montmorillonite. Results revealed a relation between four phases of ps development and evolution of four states of interlayer water molecule arrangement of montmorillonite (L): when ps reached its first peak in phase I, L moved from 1 row water arrangement (1w) to at least 2w; when ps decreased and re-increased in phases II or III, L moved from 2w to at least 3w; and when ps reached a steady state in phase IV, L = 3w. The w distribution in the compacted bentonite was also measured as water absorption time increased. Based on those results, the global water movement was estimated in terms of diffusivity (D) following a method employing Boltzmann transform. Results of comparisons implied that D calculated using this method matched experimental data well and the method was rather easily handled.

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