Mössbauer effect in the system Ca2Fe2O5-Ca2FeAlO5

1967 ◽  
Vol 20 (5) ◽  
pp. 859 ◽  
Author(s):  
HJ Whitfield
Keyword(s):  
Magnetic Structure ◽  
Octahedral Site ◽  
Mössbauer Spectra ◽  
Mossbauer Spectrum ◽  
Ferric Ions ◽  
Mossbauer Effect ◽  
Mossbauer Spectra ◽  
Tetrahedral Sites ◽  
Hyperfine Splittings ◽  
Calcium Ferrites

Mossbauer spectra were measured on Ca2Fe2O5, Ca2Fe1.5Al0.5O5, Ca2FeAlO5, and Ca2Fe0.67Al1.33O5 at temperatures from 95�K to above the Neel points. The Mossbauer spectrum of Ca2Fe2O5 below its Neel point shows lines which were assigned to tetrahedral and octahedral site ferric ions on the basis of the observed isomer shifts and hyperfine splittings. The Mossbauer spectra of the aluminium-substituted calcium ferrites give unequivocal evidence that the aluminium goes preferentially into tetrahedral sites. A four-sublattice magnetic structure is suggested for Ca2Fe2O5.

Study of the interaction of Pu(IV) and Np(IV,V,VI) with Fe hydroxides to predict the behavior of actinides in environmental media

2001 ◽  
Vol 89 (2) ◽  
Author(s):  
M. S. Grigoriev ◽  
A. M. Fedosseev ◽  
A.V. Gelis ◽  
N.A. Budantseva ◽  
V.P. Shilov ◽  
...  
Keyword(s):  
Mössbauer Effect ◽  
Mössbauer Spectra ◽  
Mossbauer Effect ◽  
Environmental Media ◽  
Mossbauer Spectra ◽  
Effect Method

A Mössbauer effect method was used to study the formation of mixed hydroxides in the alkaline coprecipitation of Pu(IV) or Np(IV) with Fe(III). The Mössbauer spectra of mixed

Positive Temperature Dependence of Quadrupole Splittings in Mössbauer Spectra of Fe1.33Nb2.67Se10

2002 ◽  
Vol 57 (6-7) ◽  
pp. 627-630 ◽  
Author(s):  
Takashi Suzuki ◽  
Noriaki Okubo
Keyword(s):  
Temperature Dependence ◽  
Mössbauer Effect ◽  
Mössbauer Spectra ◽  
Positive Temperature ◽  
Mossbauer Effect ◽  
Mossbauer Spectra ◽  
Positive Temperature Dependence ◽  
Low Dimensional

The Mössbauer effect in the low-dimensional compound Fe1.33Nb2.67Se10 has been examined between 78 and 414 K. An anusual positive temperature dependence of the quadrupole splittings was found above 250 K. As a possible origin a mechanism due to π bonding is suggested

scholarly journals Variation of Quadrupole Splitting in Modified Oxyhemoglobin: A Mössbauer Effect Study

2000 ◽  
Vol 55 (1-2) ◽  
pp. 193-198 ◽  
Author(s):  
M. I. Oshtrakh ◽  
O. B. Milder ◽  
V. A. Semionkin ◽  
A. L. Berkovsky ◽  
M. A. Azhigirova ◽  
...  
Keyword(s):  
Quadrupole Splitting ◽  
Mössbauer Spectra ◽  
Effect Study ◽  
Heme Iron ◽  
Mossbauer Effect ◽  
Frozen Solution ◽  
Mossbauer Spectra ◽  
Human Adult ◽  
Adult Hemoglobin ◽  
Α And Β Subunits

Human adult hemoglobin modified by both pyridoxal-5'-phosphate and glutaraldehyde in the oxy-form was studied by Mössbauer spectroscopy. Mössbauer spectra were measured at 87 and 295 K (hemoglobin in lyophilized form) and at 87 K (hemoglobin in frozen solution). The values of the quadrupole splitting for modified oxyhemoglobin were found to be lower then those of oxyhemoglobin without modifications in lyophilized form and frozen solution, respectively. The Mössbauer spectra of modified oxyhemoglobin were also analyzed in terms of the heme iron inequivalence in α-and β-subunits of the tetramer. Differences of the tendencies of temperature dependencies of quadrupole splitting for modified and non-modified oxyhemoglobin in lyophilized form were shown.

Mössbauer and X-ray data on β-FeOOH (akaganéite)

Clay Minerals ◽  
1979 ◽  
Vol 14 (4) ◽  
pp. 273-283 ◽  
Author(s):  
E. Murad
Keyword(s):  
Room Temperature ◽  
Mössbauer Spectra ◽  
Unit Cell ◽  
Mossbauer Spectrum ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Mossbauer Spectra ◽  
Hydrolysis Of

Abstractβ-FeOOH (akaganéite) was prepared by slow hydrolysis of an FeCl3 solution. X-ray diffraction measurements gave refined unit-cell parameters of a=10·535 Å, c=3·030 Å.Two doublets with δ(Fe)=0·39, ΔEQ=0·95, and δ=0·38, ΔEQ=0·55 mm s−1, respectively, can be fitted to the Mössbauer spectrum taken at room temperature.Magnetically split Mössbauer spectra were registered at 135 and 4°K. These can be resolved into at least three superimposed sextets, corresponding to different Fe3+ sites in the β-FeOOH structure. At 4°K a three sextet model gives parameters of δ=0·36, ΔEQ=0·90, Hi=473; δ=0·35, ΔEQ=0·30, Hi=479; and δ=0·37, ΔEQ=−0·05 mm s−1, Hi=486kOe, respectively.The complexity of the Mössbauer spectra of β-FeOOH limits the usefulness of this method as a tool for the identification of akaganéite in composite natural samples.

The 125Te Mössbauer Absorption Spectra of the Thiourea, Ethylenethiourea, and Tetramethylthiourea Derivatives of Tellurium(II) and Tellurium(IV)

1972 ◽  
Vol 50 (22) ◽  
pp. 3677-3685 ◽  
Author(s):  
B. M. Cheyne ◽  
C. H. W. Jones ◽  
P. Vasudev
Keyword(s):  
Isomer Shift ◽  
Quadrupole Splitting ◽  
Absorption Spectra ◽  
Mössbauer Spectra ◽  
Mossbauer Spectrum ◽  
Mössbauer Spectrum ◽  
Mossbauer Spectra ◽  
Derivatives Of ◽  
Bonding Scheme

The 125Te Mössbauer spectra of a number of Te(II) and Te(IV) complexes of thiourea and related derivatives have been measured. The isomer shifts and quadrupole splittings for several of the compounds are interpreted in terms of a bonding scheme utilizing three-center, two-electron bonds in which the tellurium 5p orbitals participate. The 129I Mössbauer spectrum of trans-TeEtu2129I2 is reported and the isomer shift and quadrupole splitting are shown to be consistent with the proposal that the iodine uses only a 5p orbital in bonding to the tellurium.

The role of iron in the weathering of a climosequence of soils derived from schist

Soil Research ◽  
1991 ◽  
Vol 29 (3) ◽  
pp. 387 ◽  
Author(s):  
LP Aldridge ◽  
GJ Churchman
Keyword(s):  
New Zealand ◽  
Mössbauer Spectra ◽  
Ferric Ions ◽  
Ferrous Ions ◽  
Rock Samples ◽  
Mossbauer Spectra ◽  
Muscovite Mica ◽  
Primary Minerals ◽  
Close Parallel

Mossbauer spectra were obtained of the whole soil and clay fractions and some of the sand fractions, as well as some rock samples that were taken from eight soils forming a climosequence on schist in South Island, New Zealand. They show that the main changes in iron across the sequence involve the oxidation of ferrous ions in muscovite mica and its initial weathering products to ferric ions in these minerals and also in oxyhydroxides. The extremes of weathering in the sequence led to the mobilization of iron from primary minerals in soils at the surface of profiles into oxyhydroxides that were deposited lower down in these profiles. While these changes in iron have occurred alongside the loss of K+ from the interlayers of the micas to form expanded phases, there is not a close parallel between the changes on oxidation and those from the initial loss of interlayer potassium.

scholarly journals Hyperfine structure of [57Fe]iron in the Mössbauer spectrum of the high-potential iron protein from Chromatium

1970 ◽  
Vol 119 (2) ◽  
pp. 289-291 ◽  
Author(s):  
M. C. W. Evans ◽  
D. O. Hall ◽  
C. E. Johnson
Keyword(s):  
Hyperfine Structure ◽  
Mössbauer Spectra ◽  
High Potential ◽  
Magnetic Hyperfine ◽  
Mossbauer Spectrum ◽  
Hyperfine Fields ◽  
Iron Protein ◽  
57Fe Mössbauer ◽  
Mossbauer Spectra ◽  
Magnetic Hyperfine Structure

The magnetic hyperfine structure observed in the 57Fe Mössbauer spectra of the high-potential iron protein from Chromatium shows that the iron atoms are inequivalent in pairs, with hyperfine fields of 121 and 90kG.

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