Rossiantonite, Al3(PO4)(SO4)2(OH)2(H2O)10{middle dot}4H2O, a new hydrated aluminum phosphate-sulfate mineral from Chimanta massif, Venezuela: Description and crystal structure

2013 ◽  
Vol 98 (10) ◽  
pp. 1906-1913 ◽  
Author(s):  
E. Galli ◽  
M. F. Brigatti ◽  
D. Malferrari ◽  
F. Sauro ◽  
J. De Waele
Keyword(s):  
Crystal Structure ◽  
Aluminum Phosphate ◽  
Hydrated Aluminum

Crystal structure of a new microporous Na2{Al3(OH)2[PO4]3} aluminum phosphate

2003 ◽  
Vol 48 (5) ◽  
pp. 209-215 ◽  
Author(s):  
O. V. Yakubovich ◽  
O. V. Dimitrova ◽  
V. S. Urusov
Keyword(s):  
Crystal Structure ◽  
Aluminum Phosphate

The Preparation and Characteristics of MMT Nanosheets

2013 ◽  
Vol 544 ◽  
pp. 152-155
Author(s):  
Cheng Chen ◽  
Hao Wu ◽  
Qiang Li
Keyword(s):  
Crystal Structure ◽  
Chemical Method ◽  
Ph Value ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Aluminum Silicate ◽  
Practical Applications ◽  
The Status ◽  
Hydrated Aluminum ◽  
The Impact

Montmorillonite (MMT) mainly consist of hydrated aluminum silicate. Montmorillonite has particular properties and many practical applications, because of their special crystal structure. Here, mechano-chemical method was used to prepare MMT nanosheets by controlling the pH value. MMT nanosheets were obtained by ballmilling, and the impact of pH value on the nanosheets preparing was studied. TEM was employed to emamine the microstructure of MMT nanosheets. The size are analyzed to study the status of MMT nanosheets. Different rare earth ions as a fluorescence center were assembled on nanosheets，and composites were obtained. The luminescent properties of composite materials were studied.

A model for the structure of the hydrated aluminum phosphate, kingite determined by ab initio powder diffraction methods

2003 ◽  
Vol 88 (1) ◽  
pp. 235-239 ◽  
Author(s):  
Kia S. Wallwork ◽  
Allan Pring ◽  
Max R. Taylor ◽  
Brett A. Hunter
Keyword(s):  
Ab Initio ◽  
Powder Diffraction ◽  
Aluminum Phosphate ◽  
Hydrated Aluminum

Crystal Structure of Tetrapropylammonium Hydroxide—Aluminum Phosphate Number 5

1983 ◽  
pp. 109-118 ◽  
Author(s):  
J. M. BENNETT ◽  
J. P. COHEN ◽  
EDITH M. FLANIGEN ◽  
J. J. PLUTH ◽  
J. V. SMITH
Keyword(s):  
Crystal Structure ◽  
Aluminum Phosphate ◽  
Tetrapropylammonium Hydroxide

Diagenetic fluorapatite and aluminum phosphate–sulphate in the Paleoproterozoic Thelon Formation and Hornby Bay Group, northwestern Canadian Shield

2006 ◽  
Vol 43 (5) ◽  
pp. 617-629 ◽  
Author(s):  
Q Gall ◽  
J A Donaldson
Keyword(s):  
Earth Element ◽  
Aluminum Phosphate ◽  
Canadian Shield ◽  
Northwestern Part ◽  
Athabasca Basin ◽  
Thelon Basin ◽  
Hydrated Aluminum ◽  
Element Bearing ◽  
Diagenetic Fluids ◽  
Lines Of Evidence

In the northwestern part of the Canadian Shield, fluorapatite and a rare-earth element-bearing hydrated aluminum phosphate–sulphate mineral (APS) occur as cements in continental successions near the base of the Paleoproterozoic Thelon Formation (Thelon Basin) and Hornby Bay Group (Hornby Bay Basin). These minerals occupy interstitial sites, form euhedral crystals, display micro-scale zonation, make up part of an unmetamorphosed paragenetic assemblage, and are distributed in correlative units across thousands of square kilometres, suggesting a diagenetic origin. Stratigraphy, geochronology, and other lines of evidence suggest that the Thelon Formation and Hornby Bay Group containing these phosphatic cements, as well as the Ellice Formation and Athabasca Group, are correlative and may have been originally interconnected. The evidence suggests that the basal Thelon Formation and the Hornby Bay Group underwent similar, and approximately coeval, diagenetic mineral paragenesis. Furthermore, the diagenetic fluids in these different locations must have been remarkably similar, especially those that produced the delicate APS mineral. Compared to phosphatic cements in the Hornby Bay and Thelon basins, unmineralized sandstone in the Athabasca Basin contains "crandallite group" and fluorapatite cements higher in the basin fill sequence (Wolverine Point Formation) in tuffaceous sandstone and as relatively early cement in the paragenetic sequence.

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

Transmission Electron Microscopy studies of the vacancy ordering in YSI2-X thin films

1991 ◽  
Vol 49 ◽  
pp. 562-563
Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thin Films ◽  
Diffraction Pattern ◽  
Annealing Temperature ◽  
Lattice Mismatch ◽  
Si Substrate ◽  
Metal Thin Films ◽  
Transmission Electron ◽  
Vacancy Ordering

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

Crystal Structure Analysis of Cu-Zr Alloys by Convergent Beam Diffraction

1981 ◽  
Vol 39 ◽  
pp. 354-355
Author(s):  
A. F. Marshall ◽  
J. W. Steeds ◽  
D. Bouchet ◽  
S. L. Shinde ◽  
R. G. Walmsley
Keyword(s):  
Crystal Structure ◽  
Point Group ◽  
Intermetallic Phase ◽  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Ion Milling ◽  
Composition And Structure ◽  
Unit Cells ◽  
Sputter Deposited ◽  
Convergent Beam

Convergent beam electron diffraction is a powerful technique for determining the crystal structure of a material in TEM. In this paper we have applied it to the study of the intermetallic phases in the Cu-rich end of the Cu-Zr system. These phases are highly ordered. Their composition and structure has been previously studied by microprobe and x-ray diffraction with sometimes conflicting results.The crystalline phases were obtained by annealing amorphous sputter-deposited Cu-Zr. Specimens were thinned for TEM by ion milling and observed in a Philips EM 400. Due to the large unit cells involved, a small convergence angle of diffraction was used; however, the three-dimensional lattice and symmetry information of convergent beam microdiffraction patterns is still present. The results are as follows:1) 21 at% Zr in Cu: annealed at 500°C for 5 hours. An intermetallic phase, Cu3.6Zr (21.7% Zr), space group P6/m has been proposed near this composition (2). The major phase of our annealed material was hexagonal with a point group determined as 6/m.

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