Formation of iron nodules in a Hapludult of central Taiwan

2003 ◽  
Vol 83 (2) ◽  
pp. 167-172 ◽  
Author(s):  
C. W. Pai ◽  
M. K. Wang ◽  
H. C. Chiang ◽  
H. B. King ◽  
J. -L. Hwong ◽  
...  
Keyword(s):  
Key Words ◽  
Mass Spectroscopy ◽  
Clay Mineralogy ◽  
X Ray Diffraction ◽  
Soil Matrix ◽  
X Ray ◽  
Associated Matrix ◽  
Central Taiwan ◽  
Weathering Process ◽  
Surrounding Soil

This study compared iron nodules with their matrix materials in a Hapludult from central Taiwan. Mineralogy and 14C ages of the iron nodules were compared with their associated matrix materials. The samples were analyzed by X-ray diffraction (XRD) and accelerated mass spectroscopy (AMS). Hydroxy-interlayered vermiculite (HIV) and illite were the major clay minerals in the soil matrix, but illite and kaolinite were dominant in the iron nodules. Clay mineralogy of iron nodules revealed more intense weathering process than the surrounding soil matrix. 14C dates showed that the age of saprolite and iron nodules were similar, and were both much older than those of the soil matrix. It is suggested that iron nodules developed from residuum of the Tertiary shale (saprolite). During pedogenesis, saprolite acted as a nucleus, where Fe coated on its surface was transferred to form iron nodules. Key words: 14C dates, iron nodules, saprolite, soil matrix, Ultisol

scholarly journals Provenance and Sedimentary Context of Clay Mineralogy in an Evolving Forearc Basin, Upper Cretaceous-Paleogene and Eocene Mudstones, San Joaquin Valley, California

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 71
Author(s):  
Andrew Hurst ◽  
Michael Wilson ◽  
Antonio Grippa ◽  
Lyudmyla Wilson ◽  
Giuseppe Palladino ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Upper Cretaceous ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Bulk Rock ◽  
X Ray Diffraction ◽  
Arc Volcanism ◽  
X Ray ◽  
Magmatic Arc ◽  
Tropical Weathering

Mudstone samples from the Moreno (Upper Cretaceous-Paleocene) and Kreyenhagen (Eocene) formations are analysed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) to determine their mineralogy. Smectite (Reichweite R0) is the predominant phyllosilicate present, 48% to 71.7% bulk rock mineralogy (excluding carbonate cemented and highly bio siliceous samples) and 70% to 98% of the <2 μm clay fraction. Opal CT and less so cristobalite concentrations cause the main deviations from smectite dominance. Opal A is common only in the Upper Kreyenhagen. In the <2 μm fraction, the Moreno Fm is significantly more smectite-rich than the Kreyenhagen Fm. Smectite in the Moreno Fm was derived from the alteration of volcaniclastic debris from contemporaneous rhyolitic-dacitic magmatic arc volcanism. No tuff is preserved. Smectite in the Kreyenhagen Fm was derived from intense sub-tropical weathering of granitoid-dioritic terrane during the hypothermal period in the early to mid-Eocene; the derivation from local volcanism is unlikely. All samples had chemical indices of alteration (CIA) indicative of intense weathering of source terrane. Ferriferous enrichment and the occurrence of locally common kaolinite are contributory evidence for the intensity of weathering. Low concentration (max. 7.5%) of clinoptilolite in the Lower Kreyenhagen is possibly indicative of more open marine conditions than in the Upper Kreyenhagen. There is no evidence of volumetrically significant silicate diagenesis. The main diagenetic mineralisation is restricted to low-temperature silica phase transitions.

THE CLAY MINERALS IN SOME BRITISH COLUMBIA SUBSOILS

1962 ◽  
Vol 42 (2) ◽  
pp. 296-301 ◽  
Author(s):  
J. S. Clark ◽  
J. E. Brydon ◽  
H. J. Hortie
Keyword(s):  
British Columbia ◽  
Diffraction Analysis ◽  
Clay Minerals ◽  
Clay Mineralogy ◽  
X Ray Diffraction ◽  
The South ◽  
Parent Materials ◽  
X Ray ◽  
Northeastern Part ◽  
Montmorillonitic Clay

X-ray diffraction analysis was used to identify the clay minerals present in fourteen subsoil samples that were selected to represent some more important clay-bearing deposits in British Columbia. The clay mineralogy of the subsoils varied considerably but montmorillonitic clay minerals tended to predominate in the water-laid deposits of the south and illite in the soil parent materials of the Interior Plains region of the northeastern part of the Province.

Crystal structures of highly stabilized ylides: methyl(3-methoxy,2-methoxycarbonylbenzoyl) triphenyl- phosphoranylideneacetate and methyl(2-methoxycarb-6-nitrobenzoyl)triphenyl phos phoranyl ideneacetate and the salt methyl(triphenylphosphoranylidene)acetate tetrafluoroborate

1998 ◽  
Vol 76 (12) ◽  
pp. 1844-1852
Author(s):  
Fernande D Rochon ◽  
Robert Melanson ◽  
Margaret M Kayser
Keyword(s):  
Key Words ◽  
Crystal Structures ◽  
Nitro Derivative ◽  
Transient Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ionic Salt ◽  
Higher Temperature ◽  
Cyclic Anhydrides ◽  
Wittig Reactions

At lower temperatures stabilized ylides react with unsymmetrically substituted phthalic anhydrides to give two acyclic adducts. When the reactions are allowed to proceed at higher temperature enol lactones are formed. Identification of the acyclic intermediates was necessary to understand the mechanism of these Wittig reactions. The transient species trapped in the reaction with trimethyloxonium tetrafluoroborate were unambiguously identified by crystallographic methods. The crystal structures of the tetrafluoroborate salt of methyl(triphenylphosphoranyl idene)- acetate (8), methyl(3-methoxy,2-methoxycarbonylbenzoyl)triphenylphosphoranylideneacetate (6β), and methyl(2-methoxycarbonyl,6-nitrobenzoyl)triphenylphosphoranylideneacetate (7α) were studied by X-ray diffraction. The ionic salt (8) is monoclinic, P21c,a= 12.640(5), b = 13.945(9), c = 14.825(6) Å, β = 125.32(3)°, Z = 4, and R = 0.065 (F >5.4 σ(F)). Crystal 6 β is monoclinic, P21c,a = 16.391(16), b = 9.029(6), c = 19.835(19) Å, β = 116.60(6)°, Z = 4, and R = 0.070 (F > 4.6 σ(F)), while crystal 7α is also monoclinic, P21c,a = 9.513(5), b = 9.361(3), c = 30.908(13) Å, β = 98.42(3)°, Z = 4, and R = 0.057 (F >5 σ(F)). In the BF 4- salt (12), the four P-C distances are equal (1.791(5)-1.801(7) Å) with identical tetrahedral angles. For the two triphenylphosphoranylideneacetate compounds, the fourth P-C(1) bond is shorter (1.762(6)-1.734(5) Å) than the three P-C(Ph) bonds (avg. 1.809(5) Å). The angles C(1)-P-C(Ph) are also larger (avg. 112.9(2)° for 6β and 111.9(2)° for 7α) than the C(Ph)-P-C(Ph) angles (avg. 105.8(2)° for 6 β and 106.9(2)° for 7α). These values suggest a multiple nature for the P-C(1) bond. In the nitro derivative, the nitro and the ester groups are disordered equally in positions 2 and 6. Key words: Wittig reactions, cyclic anhydrides, stabilized ylide, phosphoranylidenes, crystal structures.

Are mesoionic compounds aromatic?

1998 ◽  
Vol 76 (6) ◽  
pp. 869-872 ◽  
Author(s):  
Alfredo Mayall Simas ◽  
Joseph Miller ◽  
Petrônio Filgueiras de Athayade Filho
Keyword(s):  
Experimental Evidence ◽  
Key Words ◽  
Dipole Moments ◽  
The Other ◽  
Side Chain ◽  
Theoretical Studies ◽  
X Ray Diffraction ◽  
Ring Plane ◽  
X Ray ◽  
Single Bonds

We have evaluated the experimental evidence relevant to the structure and character of mesoionic compounds, accumulated for more than 100 years and including X-ray diffraction studies. We have also evaluated relevant theoretical studies. All these, including our own extensive work, lead us to conclude that mesoionic compounds are not aromatic. According to our recent definition “mesoionic compounds are planar five-membered heterocyclic betaines with at least one side chain whose α-atom is also in the ring plane and with dipole moments of the order of 5 D. Electrons are delocalized over two regions separated by what are essentially single bonds. One region, which includes the a-atom of the side chain is associated with the HOMO and negative π-charge whereas the other is associated with the LUMO and positive π-charge.” Key words: mesoionic compounds, betaines, aromaticity.

scholarly journals Histological and X-ray structural analysis of the conditionof the bone tissue of the jaws with direct and delayed implantation using implants with different surface microstructures

2021 ◽  
Vol 108 (4) ◽  
pp. 24-32
Author(s):  
P. Grishin ◽  
◽  
E. Mamaeva ◽  
E. Kalinnikova ◽  
E. Kushner ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Key Words ◽  
Bone Tissue ◽  
Animal Experiment ◽  
Histological Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Delayed Implantation ◽  
Surface Microstructures ◽  
Bone Condition

Abstract. This article presents the results of histological and X-ray studies of bone condition, stability, and degree of osteointegration of implants with different microstructure of the surface during immediate and delayed implantation in the animal experiment. The results of the study did not reveal significant differences in the process of osteointegration during direct and delayed implantation. Data from histological and X-ray studies of direct implantation in fresh extraction holes are comparable to those obtained during delayed implantation and are not inferior to the traditional two-stage protocol. At the same time, a certain correlation between the type of surface of the implant and the time of its adaptation in different periods of the experiment was revealed. When using an implant with an innovative surface, HSTTM. The process of osteointegration is mor clear, and the bone wall of the hole is more compacted, which indicates an accelerated and successful process of osteointegration. Key words: X-ray diffraction, frequency resonance and histological analysis, fibrous capsule, collagen fibers, trabeculae, bone tissue, periotestometry osseointegration, stability.

EFFECT OF SOIL ORGANIC MATTER OXIDATION ON THE COLLAPSE OF VERMICULITE

1985 ◽  
Vol 65 (3) ◽  
pp. 593-597 ◽  
Author(s):  
N. M. MILES ◽  
M. SCHNITZER ◽  
C. R. DE KIMPE
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Key Words ◽  
Mixed Layer ◽  
Ir Spectrum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organic Matter Oxidation ◽  
Ir Spectrophotometry ◽  
Complete Collapse

Oxidation of organic matter with H2O2 produced substantial amounts of NH3 which was then fixed by vermiculite, causing partial or complete collapse and converting the mineral to a mica-like product. The collapse of the mineral was indicated by shifts in the 001 spacing from 1.476 to 1.030 nm and the appearance of a well-defined band at 1430 cm−1 in the IR spectrum, indicative of the presence of NH4+ in the interlayer positions of the clay. Our data suggest that: (a) the transformation of vermiculite to mica during H2O2 oxidation may result in underestimation of the vermiculite content of soils by XRD, and (b) the wide occurrence of mixed-layer minerals in soils may in part have resulted from the fixation of NH3 liberated from the microbial mineralization of organically bound N. Key words: Ammonia, X-ray diffraction, IR spectrophotometry, mixed-layer minerals, H2O2 pretreatment

Structure cristalline et moléculaire d'un composé tricyclique contenant le cycle à dix chaînons dioxo diaza diphosphécine

1992 ◽  
Vol 70 (3) ◽  
pp. 809-816 ◽  
Author(s):  
Brigitte Duthu ◽  
Karim El Abed ◽  
Douraid Houalla ◽  
Robert Wolf ◽  
Joël Jaud
Keyword(s):  
Molecular Structure ◽  
Comparative Analysis ◽  
Double Bond ◽  
Mass Spectroscopy ◽  
Crystal And Molecular Structure ◽  
Accurate Information ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Parameters ◽  
C Nmr

The sulfuration of the tricyclic organophosphorous dimer 2 leads easily to the dithiotricyclic derivative 3, which has been characterized by 31P, 1H, and 13C NMR, elemental analysis, and mass spectroscopy. Its crystal and molecular structure has been established by X-ray diffraction and compared to that of 2, which was previously determined. The comparative analysis of X-ray diffraction and NMR parameters gives accurate information about the molecular structure of both compounds. A numerical value of the anistropy cone of the P=S double bond is proposed. Keywords: phosphecine, NMR, X-ray, tricycle.

scholarly journals Understanding H2 Evolution from the Decomposition of Dibutylmagnesium Isomers Using in-Situ X-ray Diffraction Coupled with Mass Spectroscopy

2019 ◽  
Vol 2 (7) ◽  
pp. 5272-5278 ◽  
Author(s):  
Jian Liu ◽  
H. Todd Schaef ◽  
Paul F. Martin ◽  
B. Pete McGrail ◽  
Leonard S. Fifield
Keyword(s):  
Mass Spectroscopy ◽  
H2 Evolution ◽  
X Ray Diffraction ◽  
X Ray

Clay mineralogy of sediments of the western Nile Delta

Clay Minerals ◽  
1975 ◽  
Vol 10 (5) ◽  
pp. 369-386 ◽  
Author(s):  
A. H. Weir ◽  
E. C. Ormerod ◽  
I. M. I. El Mansey
Keyword(s):  
Mineral Composition ◽  
Nile Delta ◽  
Clay Mineralogy ◽  
Clay Content ◽  
Selective Dissolution ◽  
Layer Silicate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Sites ◽  
Clay Mineral Composition

AbstractInvestigation of the clay mineralogy of forty-seven samples of sediments from boreholes in the western Nile Delta, an area little studied hitherto, and from surface sites on the mouth of the Nile and adjacent coast shows that the clay fractions consist of dominant iron-rich, dioctahedral, randomly interstratified smectite-illitcs together with kaolinite, illite and chlorite.Amounts of the constituent minerals of the clay fractions are estimated from their X-ray diffraction intensities, supported by selective dissolution chemical data, and a new method is used to estimate the proportion of expanding layers in randomly interstratified smectite-illite. The results, which confirm and extend the work of previous investigators, also show that there is little correlation between the clay mineral composition and texture of the sediments, only kaolinite being weakly linearly correlated with clay content. Transformation of 2:1 layer silicate minerals occurs within the buried sediments ; chlorite is transformed and smectite and illite interlayers redistributed within randomly interstratified smectite-illites.

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