Electron Probe Microanalysis of Zinc-Bearing Hexagonal Ferrites

1965 ◽  
Vol 9 ◽  
pp. 304-313
Author(s):  
J. R. Shappirio
Keyword(s):  
Electron Probe ◽  
Hexagonal Ferrites ◽  
Structural Units ◽  
Electron Probe Analysis ◽  
X Ray ◽  
Layer Structures ◽  
Cell Data ◽  
Unit Cell Data ◽  
The Ideal

AbstractThe electron probe is shown to be an effective tool for the analysis of the series of ferrimagnetic oxides referred to as the hexagonal ferrites. This series of compounds) containing barium, Fe3+, and a divalent metal cation, is formed by an ordered stacking of basic structural units in varying ratios. The ideal, complex stoichiornewy of these polytype-like mixed-layer structures can be computed from X-ray unit cell data; the various structures and their predicted stoichiometry are reviewed. Results of electron probe analysis of zinc-bearing single-crystal hexagonal ferrites are compared with theoretical values, the various correction procedures applied to the probe data are presented, and the limitations of the method in the analysis of hexagonal ferrites are discussed. The information obtained from this study has laid the groundwork for the determination of chemistry in substituted members of the hexagonal ferrite group, and will contribute significantly to the interpretation of the magnetic properties exhibited by these compounds.

Reduction of Potassium in Kidney Proximal Tubules to Aid in Electron Probe X-Ray Microanalysis of Calcium

1985 ◽  
Vol 43 ◽  
pp. 474-475
Author(s):  
A. LeFurgey ◽  
P. Ingram ◽  
L.J. Mandel
Keyword(s):  
Smooth Muscle ◽  
Proximal Tubule ◽  
Electron Probe ◽  
Clinical Applications ◽  
Proximal Tubules ◽  
Rabbit Kidney ◽  
Target Cells ◽  
X Ray ◽  
Freeze Dried

For quantitative determination of subcellular Ca distribution by electron probe x-ray microanalysis, decreasing (and/or eliminating) the K content of the cell maximizes the ability to accurately separate the overlapping K Kß and Ca Kα peaks in the x-ray spectra. For example, rubidium has been effectively substituted for potassium in smooth muscle cells, thus giving an improvement in calcium measurements. Ouabain, a cardiac glycoside widely used in experimental and clinical applications, inhibits Na-K ATPase at the cell membrane and thus alters the cytoplasmic ion (Na,K) content of target cells. In epithelial cells primarily involved in active transport, such as the proximal tubule of the rabbit kidney, ouabain rapidly (t1/2= 2 mins) causes a decrease2 in intracellular K, but does not change intracellular total or free Ca for up to 30 mins. In the present study we have taken advantage of this effect of ouabain to determine the mitochondrial and cytoplasmic Ca content in freeze-dried cryosections of kidney proximal tubule by electron probe x-ray microanalysis.

Structural and vibrational studies of 1,1,3,3-tetracyanopropane and 2,2,4,4,6-pentacyanocyclohexenamine

1987 ◽  
Vol 65 (2) ◽  
pp. 261-270 ◽  
Author(s):  
R. A. Bell ◽  
B. E. Brown ◽  
M. Duarte ◽  
H. E. Howard-Lock ◽  
C. J. L. Lock
Keyword(s):  
Unit Cell ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Methods ◽  
Cell Dimensions ◽  
Cell Data ◽  
Unit Cell Data ◽  
Monoclinic Cell ◽  
C Nmr

1,1,3,3-Tetracyanopropane, 1, was prepared in low yields by a literature method with 2,2,4,4,6-pentacyanocyclohexenamine, 2, as a major by-product. The products were examined by X-ray crystallography. 1 has an orthorhombic space group, Pbcn (No. 60) with cell dimensions, a = 7.158(2), b = 10.510(3), c = 9.733(2) Å and has four formula units in the unit cell. 2 has a monoclinic cell, P21/c (No. 14) with cell dimensions a = 14.368(3), b = 6.626(1), c = 12.300(2) Å, β = 115.60(1)° and has 4 formula units in the unit cell. Data were collected with use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structures were determined by standard methods and refined to Rw = 0.037 (1) and Rw = 0.040 (2) on the basis of 782 and 2108 unique reflections. Bond lengths and angles in the two compounds are normal. 2 has what has been considered to be the less likely tautomeric structure. Both compounds were examined by 1H, 13C nmr, vibrational spectroscopy, and mass spectroscopy. For 2 there was no evidence of the alternative tautomeric structure. New methods were developed for the preparation of both compounds and the mechanism of the original reaction rationalized.

A note on the occurrence of chevkinite, allanite, and zirkelite on St. Kilda, Scotland

1982 ◽  
Vol 46 (341) ◽  
pp. 445-448 ◽  
Author(s):  
R. R. Harding ◽  
R. J. Merriman ◽  
P. H. A. Nancarrow
Keyword(s):  
Rare Earth ◽  
Great Britain ◽  
Electron Probe ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
Electron Probe Analysis ◽  
Accessory Minerals ◽  
X Ray ◽  
Probe Analysis ◽  
Recorded Occurrence

AbstractThe occurrence of three accessory minerals with significant rare earth contents in Tertiary acid rocks of St. Kilda is described. Allanite, zirkelite, and chevkinite were identified by electron probe analysis (with energy-dispersive attachment) and the chevkinite confirmed by X-ray diffraction. Brief comparison is made with other Tertiary occurrences of RE minerals. This is the first recorded occurrence of chevkinite in Great Britain.

scholarly journals Kristallchemische Analyse der Stereochemie des Kations und Anions in Bis(triphenylphosphin)iminium-di(phthalocyaninato)metallaten der Selenen Erden, (PNP)[Ln(Pc2-)2]•xH2O (Ln = La, Gd, Tm; x ≤ 0,5) / Crystalchemical analysis of the stereochemistry of the cations and anions in bis(triphenylphosphine)iminium di(phthalocyaninato)metalates of the rare earth elements, (PNP)[Ln(Pc2-)2]•xH2O (Ln = La, Gd, Tm; x ≤ 0,5)

1994 ◽  
Vol 49 (6) ◽  
pp. 812-820 ◽  
Author(s):  
Mohsen Safarpour Haghighi ◽  
Andreas Franken ◽  
Heiner Homborg
Keyword(s):  
Structural Characteristics ◽  
Steric Effects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Contact Distance ◽  
The Common ◽  
Complex Salts ◽  
Cell Data ◽  
Unit Cell Data ◽  
Ir Bands

Of the isostructural series of monoclinic (PNP)[Ln(Pc)2]• xH2O compounds (Ln = La ••• Tm) the crystal structures of the complex salts of tervalent La (1), Gd (2) and Tm (3) have been determined by single crystal X-ray diffraction analysis. Unit cell data for 2: space group P21/c; a = 15.172(8), b = 20.826(2), c = 25.876(3) Å, β = 95.19(3)°, V - 8143(4) Å3, Z = 4; 1 and 3 are isostructural with 2. The lanthanide ion occupies the center of a nearly ideal square antiprism, although the two staggered phthalocyanine rings are severely distorted in an unsymmetrical funnel-shaped fashion due to electronic, steric, and packing influences in the crystal lattice. Steric effects dictate also the geometry of the PNP cation, which adopts a hybrid conformation whose structural characteristics are between the common linear and bent conformers with medium short P-N distances (1.562 Å) and large P-N-P angles in the range 165.6° (1) > 158.3° (2) > 156.1° (3). The strong IR bands at ca. 1375 cm-1 assigned to the asym. (P-N) stretch are diagnostic for this hybrid conformation. The presence of water of crystallization in the periphery of the diphthalocyanine anion is confirmed. The shortest contact distance is observed to one of the bridging nitrogen atoms of the Pc2- ligand (3.02 Å) indicating a weak (HO-H•••N) hydrogen bond

scholarly journals ELECTRON PROBE ANALYSIS OF THE CALCIUM DISTRIBUTION IN CELLS OF THE EMBRYONIC CHICK CHORIOALLANTOIC MEMBRANE I. A CRITICAL EVALUATION OF TECHNIQUES

1972 ◽  
Vol 20 (6) ◽  
pp. 401-413 ◽  
Author(s):  
JAMES R. COLEMAN ◽  
A. RAYMOND TEREPKA
Keyword(s):  
Electron Probe ◽  
Critical Evaluation ◽  
Chorioallantoic Membrane ◽  
Embryonic Chick ◽  
Total Calcium ◽  
Electron Probe Analysis ◽  
X Ray ◽  
Chick Chorioallantoic Membrane ◽  
Minor Losses

The chorioallantoic membrane of the developing chick embryo is an epithelium that actively transports calcium. The methodology utilized to prepare this soft tissue for calcium localization with the electron probe x-ray microanalyzer is presented in detail. The preparative procedures are evaluated according to general histochemical principles and in relationship specifically to electron probe investigations. It is shown that the method employed in these studies preserves the normal fine structure of the tissue, prevents selective loss of calcium, permits only minor losses of total calcium and appears to maintain the distribution of calcium that existed in vivo. Examples are presented of artifacts that can be induced during tissue sectioning and mounting procedures. Problems of defining electron probe resolution in biologic specimens are discussed, and the critical importance of evaluating x-ray images in association with simultaneously generated sample current images is emphasized.

Cosmochlore—a new examination

1981 ◽  
Vol 44 (335) ◽  
pp. 265-267 ◽  
Author(s):  
A. G. Couper ◽  
M. H. Hey ◽  
R. Hutchison
Keyword(s):  
Electron Probe ◽  
Optical Data ◽  
Electron Probe Analysis ◽  
X Ray ◽  
Probe Analysis

AbstractExamination of cotype cosmochlore from the Toluca meteorite confirms Laspeyres's observations (1897) in every respect, except that what he determined as iron was largely titanium. His data are completed by an electron-probe analysis and by full optical and X-ray data. Accepting the identity of cosmochlore and ureyite, the optical data of Frondel and Klein (1965) for the latter are partly in error or misprinted.

scholarly journals Untersuchungen am System Vanadium—Gallium

1966 ◽  
Vol 21 (5) ◽  
pp. 531-540 ◽  
Author(s):  
R. G. Maier ◽  
Y. Uzel ◽  
H. Kandler
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
Electron Probe ◽  
Liquidus Curve ◽  
X Ray Diffraction ◽  
Equilibrium Conditions ◽  
Electron Probe Analysis ◽  
X Ray ◽  
Oxygen System ◽  
Annealing Experiments

The phase diagram of the vanadium-gallium system was investigated by means of thermoanalysis, microscopy, x-ray diffraction, and electron probe analysis.The liquidus curve was measured in the range from 40—80% Gallium. The existence of the known phases V3Ga (Cr3Si-typ), V6Ga5 (Ti6Sn5-typ), V6Ga7 (Cu5Zn8-typ), V2Ga5 (Mn2Hg5-typ), V4GaO and V5Ga3Ox (Mn5Si3-typ) was reestablished. The existence of V3GaOx and V5 (Ga, Si)3Ox is stated and their crystal structure investigated.It is shown that the oxygen content of he samples greatly influences the equilibrium conditions of the system. By means of annealing experiments and dilatometric measurements the phase diagram of the vanadium-gallium-oxygen system was investigated in the range of small oxygen contents.

Barium Rare Earth Titanates: X-Ray Characterization of BaR2Ti3O10 and BaR2Ti4O12: R = Lanthanide

1992 ◽  
Vol 7 (3) ◽  
pp. 176-178 ◽  
Author(s):  
X. Jing ◽  
C. Zheng ◽  
A.R. West
Keyword(s):  
Rare Earth ◽  
Solid State ◽  
Unit Cell ◽  
Lanthanide Ion ◽  
X Ray ◽  
Ion Size ◽  
Cell Data ◽  
Unit Cell Data ◽  
Cell Volumes

AbstractThe compounds, BaR2Ti3O10: R = La, Pr, Nd and Sm; BaR2Ti4O12: R = La, Pr, Sm, Gd, Eu have been prepared by solid state reaction and characterized by X-ray powder diffraction. Unit cell data are summarised; lattice parameters and unit cell volumes increase approximately linearly with lanthanide ion size.

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