Nanostructures of the Product Sequence in the Decomposition of Mixed Rare Earth Hydroxycarbonate Colloidal Particles

1992 ◽  
Vol 272 ◽  
Author(s):  
Z. C. kang ◽  
M. J. Mckelvy ◽  
L. Eyring
Keyword(s):  
Thermal Analysis ◽  
Electron Beam ◽  
Rare Earth ◽  
Colloidal Particles ◽  
X Ray Diffraction ◽  
Decomposition Products ◽  
X Ray ◽  
Colloidal Spheres ◽  
Diffraction Patterns ◽  
Product Sequence

ABSTRACTThe decomposition of colloidal spheres of mixed rare earth hydroxycarbonate to the oxide has been studied by three methods. a) The spheres are treated in a thermal analysis apparatus up to 1100°C and afterward successive reruns were made and specimens cooled rapidly at temperatures where intermediate or final products are formed. X-ray diffraction patterns and HREM studies were made of each sample thus produced. b) The spheres were heated to 450°C in the specimen chamber of a mass spectrometer and the gaseous decomposition products were monitored continuously. c) The colloidal spheres were introduced into the electron microscope and the decomposition followed at high resolution as evolution to the oxide was induced by the electron beam. The results are compared and contrasted.

A second occurrence of lyndochite

1965 ◽  
Vol 34 (268) ◽  
pp. 237-248 ◽  
Author(s):  
J. E. T. Horne ◽  
J. R. Butler
Keyword(s):  
Heat Treatment ◽  
Rare Earth ◽  
Peak Concentration ◽  
Type Locality ◽  
X Ray Diffraction ◽  
X Ray ◽  
Suitable Heat Treatment ◽  
Diffraction Patterns ◽  
The Many ◽  
Almost All

SummaryLyndochite from Tura dukas, 35 miles north of Nanyuki, Kenya, agrees closely with the type material from Canada in its chemical analysis, in the distribution of the rare earths, and in X-ray diffraction data for powder after heat treatment. The mineral is compared and contrasted with aeschynite. Uranium-poor euxenite is intimately associated with lyndochite at the type locality.Since its discovery over thirty-five years ago, lyndochite has remained unrecorded outside its type locality of Lyndoch Township in Ontario, Canada. Its distinctive chemical composition sets it apart from almost all other Ti-rich metamiet niobates and, despite the many analyses that have been made on rare-earth niobate-tantalates, specimens that could have been regarded as similar to or approximating to lyndochite have rarely been mentioned. Its unusual characteristics include high ThO2 (about 10%) and appreciable rare-earth oxides (about 20%) with a lanthanon assemblage showing a peak concentration of Nd (and Ce), rather than any of the heavy lanthanons. The proportions of TiO2 (about 20%) and (Nb,Ta)2O5 (about 40%) are comparable to those in numerous niobate-tantalates, but are only associated with the percentages of ThO2 and Re2O3 mentioned above in some members of the aesehynite-priorite series. The lyndochite now described is chemically very close indeed to the Canadian lyndochite, and both specimens give closely similar X-ray diffraction patterns (after suitable heat treatment) which are distinct from those of any other metamict mineral.

(Rare Earth/Li) Titanates and Niobates as Ionic Conductors

2000 ◽  
Vol 658 ◽  
Author(s):  
A. Morata-Orrantia ◽  
S. García-Martín ◽  
E. Morán ◽  
U. Amador ◽  
M. A. Alario-Franco
Keyword(s):  
Rare Earth ◽  
Ionic Conductivity ◽  
Lithium Ion ◽  
Related Structure ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
X Ray ◽  
Properties Of Materials ◽  
Ion Conducting ◽  
Diffraction Patterns

ABSTRACTThe lithium ion conducting properties of materials of composition La0.58Li0.26TiO3, Nd0.58Li0.26TiO3, La0.67Li0.25Ti0.75Al0.25O3 and La0.29Li0.12NbO3 have been compared in relation with their microstructure. All the oxides have powder X-ray diffraction patterns characteristic of a perovskite-related structure with lattice parameters a∼√2ap, b∼√2ap, c∼2ap (p refers to cubic perovskite). However, some important differences are observed in their microstructure by SAED and HRTEM. Ordering between vacancies, Li+ and La3+ or Nd3+ and twinning of the NbO6 or TiO6 octahedra tilting system are shown in La0.29Li0.12NbO3 and Nd0.58Li0.26TiO3, which are the materials having a lower ionic conductivity. The La0.58Li0.26TiO3 and La0.67Li0.25Ti0.75Al0.25O3 oxides do not show ordering between cations.

scholarly journals Thermal Analysis of High Entropy Rare Earth Oxides

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3141 ◽  
Author(s):  
Sergey V. Ushakov ◽  
Shmuel Hayun ◽  
Weiping Gong ◽  
Alexandra Navrotsky
Keyword(s):  
Thermal Analysis ◽  
Rare Earth ◽  
Single Phase ◽  
Liquidus Surface ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
High Entropy ◽  
Rare Earth Sesquioxides

Phase transformations in multicomponent rare earth sesquioxides were studied by splat quenching from the melt, high temperature differential thermal analysis and synchrotron X-ray diffraction on laser-heated samples. Three compositions were prepared by the solution combustion method: (La,Sm,Dy,Er,RE)2O3, where all oxides are in equimolar ratios and RE is Nd or Gd or Y. After annealing at 800 °C, all powders contained mainly a phase of C-type bixbyite structure. After laser melting, all samples were quenched in a single-phase monoclinic B-type structure. Thermal analysis indicated three reversible phase transitions in the range 1900–2400 °C, assigned as transformations into A, H, and X rare earth sesquioxides structure types. Unit cell volumes and volume changes on C-B, B-A, and H-X transformations were measured by X-ray diffraction and consistent with the trend in pure rare earth sesquioxides. The formation of single-phase solid solutions was predicted by Calphad calculations. The melting point was determined for the (La,Sm,Dy,Er,Nd)2O3 sample as 2456 ± 12 °C, which is higher than for any of constituent oxides. An increase in melting temperature is probably related to nonideal mixing in the solid and/or the melt and prompts future investigation of the liquidus surface in Sm2O3-Dy2O3, Sm2O3-Er2O3, and Dy2O3-Er2O3 systems.

Synthesis and Structures of Rare Earth 3-(4′-Methylbenzoyl)-propanoate Complexes – New Corrosion Inhibitors

2017 ◽  
Vol 70 (5) ◽  
pp. 478 ◽  
Author(s):  
Caspar N. de Bruin-Dickason ◽  
Glen. B. Deacon ◽  
Craig M. Forsyth ◽  
Schirin Hanf ◽  
Oliver B. Heilmann ◽  
...  
Keyword(s):  
Rare Earth ◽  
Corrosion Inhibitors ◽  
Free Acid ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray ◽  
Rare Earth Chloride ◽  
Diffraction Patterns ◽  
Paramagnetic Shifts

A series of rare earth 3-(4′-methylbenzoyl)propanoate (mbp–) complexes [RE(mbp)3(H2O)] (RE = rare earth = Y, La, Ce, Nd, Ho, Er) have been prepared by either metathesis reactions between the corresponding rare earth chloride and Na(mbp) or protolysis of rare earth acetates by the free acid. Single-crystal X-ray diffraction studies of [RE(mbp)3(H2O)] (RE = Ce, Nd) and [Ce(mbp)3(dmso)] reveal a 1D carboxylate-bridged polymeric structure in the solid state, featuring 9-coordinate rare earth ions. X-ray powder diffraction patterns of the bulk materials indicates that all of the [RE(mbp)3(H2O)] complexes except RE = La are isomorphous. Hence, there is no structural change from the complex with RE = Ce to that with RE = Er despite the lanthanoid contraction. The 1H NMR spectra of the RE = Ho or Er complexes in (CD3)2SO show large paramagnetic shifts and broadening of the CH2 resonances, indicating the retention of substantial carboxylate coordination in solution.

Reflection Electron Diffraction of Catalase

1975 ◽  
Vol 33 ◽  
pp. 672-673
Author(s):  
T. K. Chatterjee ◽  
J. A. Spadaro ◽  
R. W. Vook
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Preliminary Report ◽  
Water Vapor Pressure ◽  
High Energy ◽  
High Energy Electron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Reflection Electron Diffraction

Matricardi et al. have shown that high energy electron diffraction patterns of unstained and unfixed catalase may be obtained with a high voltage TEM using a hydration stage and that without such a stage TED patterns could not be obtained. They showed that such patterns were observed only when the water vapor pressure in the vicinity of the catalase was greater than 90 percent of the equilibrium value. They attributed their results to the destruction of the crystallinity of catalase when it is vacuum dried. Similar results using X-ray diffraction techniques have been reported. Matricardi et al. also noted effects due to radiation damage, whereby the number of reflections observed using the hydration stage decreased substantially with electron beam exposure. In the present preliminary report, it is shown that electron diffraction patterns can be obtained from unstained and unfixed catalase even when the crystals are exposed directly to the vacuum of the TEM but under such conditions whereby the electron beam intensity is reduced by up to approximately two orders of magnitude from that usually obtained in normal TED work on a TEM.

Novel Catalytic Systems Based on Platinum Catalysts

2020 ◽  
Vol 299 ◽  
pp. 1033-1037
Author(s):  
G. M. Kurunina ◽  
O.M. Ivankina ◽  
G. M. Butov
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Rare Earth ◽  
Diffraction Analysis ◽  
Platinum Catalysts ◽  
X Ray Diffraction ◽  
Catalytic Systems ◽  
X Ray ◽  
Scanning Electron

The paper presents a method for the production of 1% platinum catalysts containing oxides of rare-earth elements (REE); it also dwells upon the results of analyzing such catalysts by scanning electron microscopy (SEM), x-ray diffraction analysis (XDA), and thermal analysis (DTA-TGA).

scholarly journals Synthesis of nanocomposites based on strontium stannate

2021 ◽  
Vol 340 ◽  
pp. 01049
Author(s):  
Anton Loginov ◽  
Alexandr Aparnev
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Acid Solutions ◽  
X Ray Diffraction ◽  
Decomposition Products ◽  
X Ray ◽  
Hydrochloric Acid Solutions ◽  
Strontium Stannate ◽  
Double Hydroxide ◽  
Scanning Electron

From hydrochloric acid solutions of strontium and tin(IV) by addition of ammonia until pH = 10 was obtained double hydroxide of strontium-tin(IV) SrSn(OH)6. The process of double hydroxide thermolysis and the phase composition of decomposition products were studied by differential thermal analysis, X-ray diffraction and scanning electron microscopy. It is shown that the main dehydration step is completed at a temperatureofnearly350°CandX-rayamorphousproductisformed which converts into the crystalline phase of strontium stannate at a temperature above 650°C.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

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