Spin crossover in iron(II) tris(2-(2′-pyridyl)benzimidazole) complex monitored by variable temperature methods: synchrotron powder diffraction, DSC, IR spectra, Mössbauer spectra, and magnetic susceptibility

2003 ◽  
Vol 293 (3) ◽  
pp. 375-395 ◽  
Author(s):  
R Boča ◽  
M Boča ◽  
H Ehrenberg ◽  
H Fuess ◽  
W Linert ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Ir Spectra ◽  
Powder Diffraction ◽  
Mössbauer Spectra ◽  
Spin Crossover ◽  
Variable Temperature ◽  
Mossbauer Spectra ◽  
Synchrotron Powder Diffraction

Preparation and characterization of iron oxide pillared montmorillonite

Clay Minerals ◽  
1988 ◽  
Vol 23 (4) ◽  
pp. 367-377 ◽  
Author(s):  
D. H. Doff ◽  
N. H. J. Gangas ◽  
J. E. M. Allan ◽  
J. M. D. Coey
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Powder Diffraction ◽  
Mössbauer Spectra ◽  
Pillared Clay ◽  
Cross Linking ◽  
X Ray ◽  
Pillared Montmorillonite ◽  
Mossbauer Spectra

AbstractPillared smectites in which the pillars consist of iron oxide are expected to have interesting and unusual magnetic properties. Several possible routes by which such materials might be made have been investigated, namely intercalation of hydroxy-Fe(III) polycations, mixed hydroxy-Fe(III)/Al polycations, phenanthroline-Fe(II) cations, and trinuclear Fe(III) acetato cations into Na-montmorillonite. Only the last of these yielded a pillared clay (PILC) on calcination. The products have been characterized using X-ray powder diffraction and 57Fe Mössbauer spectroscopy. The precursor Fe-PILC has a d-spacing of 21 Å and expands to 23 Å on solvation with glycol. The calcined Fe-PILC has a d-spacing of 19 Å (gallery height 9·4 Å) and does not expand with glycol, confirming cross-linking of the layers. From Mössbauer spectra at 4·2 K it is estimated that there are of the order of some hundred Fe atoms per pillar.

scholarly journals Manganese/Yttrium Codoped Strontium Nanohexaferrites: Evaluation of Magnetic Susceptibility and Mossbauer Spectra

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 24 ◽  
Author(s):  
Munirah Almessiere ◽  
Yassine Slimani ◽  
Hakan Güngüneş ◽  
Abdulhadi Baykal ◽  
S.V. Trukhanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Mössbauer Spectra ◽  
Ac Susceptibility ◽  
Sol Gel ◽  
Hyperfine Magnetic Field ◽  
Analytical Techniques ◽  
Magnetic Interactions ◽  
Mossbauer Spectra

Manganese (Mn)- and yttrium (Y)-substituted Sr-nanohexaferrites (MYSNHFs) of composition Sr1−xMnxFe12−xYxO19 (with 0.0 ≤ x ≤ 0.5) were prepared by citrate sol-gel autocombustion method. As-prepared MYSNHFs were characterized via diverse analytical techniques to determine the influence of Mn and Y cosubstitution on their microstructures and magnetic properties. 57Fe Mössbauer spectra of the MYSNHFs were used to evaluate the variation in the line width, isomer shift, quadrupole splitting, and hyperfine magnetic field values. It was shown that the dopant ions could preferentially occupy the 12k, 4f2, and 2b sites. Furthermore, the observed shift in the blocking temperatures of the studied MYSNHFs towards lower values with rising Mn2+ and Y3+ contents was attributed to the overall particles size reduction. Meanwhile, the AC susceptibility of the proposed MYSNHFs revealed that the magnetic interactions were weakened with the increase in dopant contents which was ascribed to the replacement of both Sr2+ and Fe3+ ions by the Mn2+ and Y3+ dopants.

Mössbauer studies in transition metal chemistry. IV. Iron(II) complexes of 2-(2'-Pyridyl)benzimidazole

1978 ◽  
Vol 31 (3) ◽  
pp. 487 ◽  
Author(s):  
RL Martin ◽  
IAG Roos ◽  
DML Goodgame ◽  
AASC Machado
Keyword(s):  
Temperature Dependence ◽  
Mössbauer Spectra ◽  
Spin Crossover ◽  
Complex Cation ◽  
Octahedral Symmetry ◽  
Line Lattice ◽  
Metal Chemistry ◽  
Mossbauer Spectra ◽  
Iv Iron ◽  
Mössbauer Parameters

Mossbauer spectra of a number of compounds containing the [Fe(pyb)3]2+ complex cation [pyb, 2-(2'-pyridyl)benzimidazole] confirm that these compounds undergo a change of spin state with temperature consistent with a 5T2-1A1 spin crossover. The nature of the Mossbauer spectra and their temperature-dependence are sensitive to the associated anion and the method of preparation. ��� The temperature-dependence of the Mossbauer parameters has been used to derive information about the distortions from octahedral symmetry and it is concluded that the dimensions of the crystal-line lattice are changing slightly with temperature.

scholarly journals Structures of FeII spin-crossover complexes from synchrotron powder-diffraction data

2004 ◽  
Vol 60 (5) ◽  
pp. 528-538 ◽  
Author(s):  
Eva Dova ◽  
René Peschar ◽  
Makoto Sakata ◽  
Kenichi Kato ◽  
Arno F. Stassen ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Structural Changes ◽  
Spin Crossover ◽  
Structural Model ◽  
Rietveld Method ◽  
Space Structure ◽  
Powder Diffraction Data ◽  
Synchrotron Powder Diffraction

Crystal structure determination and analysis have been carried out for the two spin-crossover compounds [Fe(teeX)6](BF4)2 (teeX is haloethyltetrazole; X = I: teei; X = Br: teeb), in both their high-spin (near 300 K) and their low-spin states (T = 90 K), using high-resolution powder-diffraction data collected at the ESRF (Grenoble, France) and SPring8 (Japan) synchrotron radiation facilities. The structures of teei have been solved using various direct-space structure determination techniques (grid search, genetic algorithm and parallel tempering) and refined with the Rietveld method using geometrical restraints. In the case of teeb, a structural model was found but a full refinement was not successful because of the presence of a significant amount of an amorphous component. Analysis of the structures (space group P21/c, Z = 2) and diffraction data, and the absence of phase transitions, show the overall structural similarity of these compounds and lead to the conclusion that the gradual spin-crossovers are likely to be accompanied by small structural changes only.

Study of NH4 + in the zeolite phillipsite by combined synchrotron powder diffraction and IR spectroscopy

2000 ◽  
Vol 56 (4) ◽  
pp. 584-593 ◽  
Author(s):  
A. F. Gualtieri
Keyword(s):  
Hydrogen Bonding ◽  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Powder Diffraction ◽  
Minor Role ◽  
Water Molecules ◽  
Absorption Bands ◽  
Synchrotron Powder Diffraction ◽  
Three Samples ◽  
A Minor

The Rietveld refinement on synchrotron data of three natural hydrated NH4 +-exchanged phillipsites with different Si/Al ratios allowed acceptable assignment of the NH4 + sites. These phillipsites display the typical monoclinic P21/m cell, whose volume increases with increasing numbers of NH4 + ions, which are refined in the two sites labelled I and II. Some residual Na+ is retained in the site labelled II′. Distortion of the Si/Al tetrahedra, which affects some absorption bands in the IR spectra, seems to be mainly due to the distribution of Al in the framework, while the interaction of NH4 + with the O atoms of the framework seems to play a minor role. NH4 + in both sites acts as a donor in hydrogen bonding with O atoms of the framework and water molecules. NH4 + in site I has three H atoms interacting with O atoms of the framework and a number of interactions with water O atoms. In all three samples, monocentric and dicentric connections are formed. NH4 + in site II has one H atom interacting with O atoms of the framework and a number of interactions with water O atoms. Two monocentric connections and a quadricentric one were found in sample (1), three dicentric connections and a monocentric one in sample (2), and three monocentric connections and a dicentric one in sample (3).

57Fe Mössbauer Spectra, Crystal Structure, and Spin-Crossover Behavior of [Fe(mbpN)(lut)]BPh4

1992 ◽  
Vol 65 (7) ◽  
pp. 1825-1831 ◽  
Author(s):  
Yonezo Maeda ◽  
Yosuke Noda ◽  
Hiroki Oshio ◽  
Yoshimasa Takashima
Keyword(s):  
Crystal Structure ◽  
Mössbauer Spectra ◽  
Spin Crossover ◽  
57Fe Mössbauer ◽  
Mossbauer Spectra ◽  
Crossover Behavior

Crystal structures and Mössbauer spectra of spin-crossover iron(III) complexes of quinquedentate ligands

1994 ◽  
Vol 84 (1) ◽  
pp. 471-476 ◽  
Author(s):  
Yonezo Maeda ◽  
Yosuke Noda ◽  
Hiroki Oshio ◽  
Yoshimasa Takashima ◽  
Naohide Matsumoto
Keyword(s):  
Crystal Structures ◽  
Mössbauer Spectra ◽  
Spin Crossover ◽  
Mossbauer Spectra

Magnetische und Mößbauer-spektroskopische Untersuchungen von zeolithischen Eisenkontakten/ Magnetic and Mössbauer Spectroscopic Studies of Iron-Clusters in Zeolites

1975 ◽  
Vol 30 (12) ◽  
pp. 1627-1632 ◽  
Author(s):  
F. Schmidt ◽  
W. Gunsser ◽  
A. Knappwost
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Mössbauer Spectra ◽  
Bulk Material ◽  
Spectroscopic Studies ◽  
Ferrous Ions ◽  
Iron Clusters ◽  
Mossbauer Spectra

Abstract Iron clusters have been prepared within zeolite holes by reduction of zeolites containing ferrous ions. The diameter of these particles must therefore be smaller than 13 Å. They are super-paramagnetic and their Mössbauer spectra show no HFS, even at 4 K.The temperature dependence of the magnetic susceptibility of the unreduced zeolites obeys a Curie-Weiss law with peff = 4,54 μB and Θ = 105 K. The Weiss curves of the reduced samples lie distinctly below those of the bulk material.

Sign in / Sign up

Export Citation Format

Share Document