A tellurium-125 Mössbauer study of bis(trifluoromethyl)- and bis(pentafluorophenyl)- tellurides and their dihalides

1986 ◽  
Vol 64 (5) ◽  
pp. 987-990 ◽  
Author(s):  
C. H. W. Jones ◽  
R. D. Sharma ◽  
D. Naumann
Keyword(s):  
Mössbauer Spectra ◽  
Electronic Excitation ◽  
Chemical Shifts ◽  
Complex Pattern ◽  
Mössbauer Study ◽  
Nmr Chemical Shifts ◽  
Mossbauer Spectra ◽  
Consistent Trend ◽  
The Mean

The 125Te Mössbauer spectra for (CF3)2Te and (C6F5)2Te have been recorded and exhibit significantly larger quadrupole splittings (14.02 and 13.40 mm s−1 respectively) than those of Me2Te (10.5 mm s−1) and Ph2Te (11.0 mm s−1). The dihalides (CF3)2TeX2 and (C66F5)2TeX2 (X = F, Cl,Br) have consistently smaller quadrupole splittings than the dihalides Me2Tex2 and Ph2TeX2. These observations are consistent with the greater electronegativity of the CF3 and C6F5 ligands. The 125Te nmr chemical shifts of (C6F5)Te and its dihalides show a consistent trend to more positive values (increased deshielding) as the electronegativity of the ligands attached to tellurium increases ((C6F5)Te, 297.6 ppm; (C6F5)2TeF2, 1060 ppm). However, for (CF3)2Te and its dihalides a more complex pattern is observed which may be explained by changes in the mean electronic excitation term in the Ramsey paramagnetic shielding term.

scholarly journals Mössbauer study of Fe phases in terrestrial olivine basalts from southern Egypt

Mineralogia ◽  
2013 ◽  
Vol 44 (1-2) ◽  
pp. 3-12 ◽  
Author(s):  
Kamaleldin M. Hassan ◽  
Julius Dekan
Keyword(s):  
Optical Microscopy ◽  
Crystal Chemistry ◽  
Mössbauer Spectra ◽  
Mossbauer Spectroscopy ◽  
X Ray Diffraction ◽  
Mössbauer Study ◽  
Hyperfine Parameters ◽  
X Ray ◽  
Mossbauer Spectra ◽  
Oxidized Iron

AbstractOlivine basalts from southern Egypt were studied by 57Fe Mössbauer spectroscopy at 297 and 77 K, and by optical microscopy and X-ray diffraction. The 57Fe Mössbauer spectra show three-magnetic sextets, three doublets of ferrous (Fe2+), and a weak ferric (Fe3+) doublet that is attributable to a nanophase oxide (npOx). The magnetic sextets relate to titanomagnetite and the Fe2+ doublets to olivine, pyroxene, and ulvöspinel. Variations in the hyperfine parameters of the various Fe components are attributed to changes in the local crystal chemistry. The intensity of oxidation (Fe3+/ΣFe) in the rocks varies from 20-27% with the oxidized iron largely residing in the titanomagnetite.

Mössbauer study of glauconites from Poland

Clay Minerals ◽  
1981 ◽  
Vol 16 (3) ◽  
pp. 221-230 ◽  
Author(s):  
A. Kotlicki ◽  
J. Szczyrba ◽  
A. Wiewióra
Keyword(s):  
Mössbauer Spectra ◽  
Mössbauer Study ◽  
Mossbauer Spectra

AbstractFour bands occur in the Mössbauer spectra of pelletal glauconites ranging in age from Cambrian to Oligocene. Components due to Fe3+ in the cis M(2) positions are visible in all the spectra but their shapes depend on the expanding layer content. In the spectrum of the Oligocene glauconite a very well-developed shoulder due to Fe2+ in the trans M(1) positions is observed. In the younger glauconites (15–20% expanding layers) the conventional assignments of the spectra indicate that Fe2+ occupies the trans M(1) positions, the cis M(2) positions being vacant. Conversely, in the Palaeozoic samples (~5% expanding layers) the cis occupancy significantly prevails over trans occupancy.

A Mössbauer study of a single crystal of the β phase of iron–germanium

1982 ◽  
Vol 60 (11) ◽  
pp. 1564-1572
Author(s):  
J. M. Daniels ◽  
H. Y. Lam ◽  
P. L. Li
Keyword(s):  
Single Crystal ◽  
Basal Plane ◽  
Mössbauer Spectra ◽  
Antiferromagnetic State ◽  
Mössbauer Study ◽  
Mossbauer Spectra ◽  
Narrow Angle ◽  
Β Phase ◽  
Line Patterns

57Fe Mössbauer spectra were obtained by scattering in a narrow angle geometry from a face, containing the basal plane, of a single crystal of the hexagonal β phase Fe1.67 Ge. Spectra were also obtained from a source of 57Co diffused into an a–c face of a single crystal of this alloy. In all cases, the spectra were satisfactorily resolved into three six-line patterns, and measurements of the relative intensities of the lines indicate that the antiferromagnetic state has a canted structure with all the spins lying in the basal plane.

Calculation of chemical shifts in the Mössbauer spectra of some tin(IV) compounds

1967 ◽  
Vol 1 (0) ◽  
pp. 51-59 ◽  
Author(s):  
N. N. Greenwood ◽  
P. G. Perkins ◽  
D. H. Wall
Keyword(s):  
Mössbauer Spectra ◽  
Chemical Shifts ◽  
Mossbauer Spectra

scholarly journals Mössbauer study of treated Nd2Fe14B

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 7-10 ◽  
Author(s):  
Mieczysław Budzyński ◽  
Virgil C. Constantin ◽  
Ana-Maria J. Popescu ◽  
Zbigniew Surowiec ◽  
Tamara M. Tkachenka ◽  
...  
Keyword(s):  
Mössbauer Spectroscopy ◽  
Grain Boundaries ◽  
Mössbauer Spectra ◽  
Mossbauer Spectroscopy ◽  
Main Phase ◽  
Surface Material ◽  
Mössbauer Study ◽  
Water Solutions ◽  
Mossbauer Spectra ◽  
Neodymium Magnets

Abstract The Nd2Fe14B cylindrical magnets were treated with water solutions of alkali, acid, and salt. Mössbauer spectroscopy was applied to study the composition and properties of the surface material of the treated magnets. It is shown that the main phase of the permanent Nd2Fe14B magnet partly decomposes. The released α-Nd at the grain boundaries interacts with water and forms neodymium hydroxide matrix, and the released Fe diffuses into it. The presence of Fe-Nd(OH)3 is reflected in the paramagnet doublet in the Mössbauer spectra of treated neodymium magnets.

Mixed oxidation state compounds of antimony: a 121Sb Mössbauer study of some antimony–fluorine systems

1978 ◽  
Vol 56 (18) ◽  
pp. 2417-2421 ◽  
Author(s):  
Jack G. Ballard ◽  
Thomas Birchall ◽  
Ronald J. Gillespie ◽  
Edward Maharajh ◽  
David Tyrer ◽  
...  
Keyword(s):  
Oxidation State ◽  
Mössbauer Spectra ◽  
Mössbauer Study ◽  
Mossbauer Spectra ◽  
Mixed Oxidation ◽  
Mössbauer Data

Antimony-121 Mössbauer spectra for [Sb2F42+][SbF6−]2 and three compounds containing the [Sb3F14−] ion are reported. The Mössbauer data are discussed in relation to their known structures. Two of the compounds give spectra which, on analysis, give η values of unity.

Résonance magnétique nucléaire 13C des dérivés allyliques de la colonne IV-A, de type (C6H5)3ECH2CH=CH—CH3. Effets électroniques du substituant du noyau aromatique

1984 ◽  
Vol 62 (1) ◽  
pp. 133-135 ◽  
Author(s):  
E. Matarasso-Tchiroukhine
Keyword(s):  
Excitation Energy ◽  
Electronic Excitation ◽  
Inductive Effect ◽  
Chemical Shifts ◽  
Aromatic Nucleus ◽  
Electronic Excitation Energy ◽  
Nmr Study ◽  
Résonance Magnétique ◽  
The Mean ◽  
C Nmr

The 13C nmr study of the series (C6H5)3ECH2CH=CH—CH31E shows, for the aromatic nucleus, a polarization consistent with a mesomeric electron withdrawing effect of the substituent in the case of E = Si, Ge, Sn; inversely, a mesomeric donating effect, in the case E = Pb, involving a higher electronegativity for Pb; and a donating π inductive effect, in the case E = C. The mean electronic excitation energy seems to dominate the chemical shifts of the aromatic carbons Cipso and Cortho, as well as the coupling 0J(13C—207Pb).

A125Te Mössbauer study of hexahalotellurates, pentahalotellurates, and tetrahaloaryltellurates

1981 ◽  
Vol 59 (6) ◽  
pp. 913-917 ◽  
Author(s):  
Nigel S. Dance ◽  
Pablo Dobud ◽  
Colin H. W. Jones
Keyword(s):  
Quadrupole Splitting ◽  
Mössbauer Spectra ◽  
Additive Model ◽  
Single Line ◽  
Mössbauer Study ◽  
Mossbauer Spectra ◽  
Mössbauer Parameters

The 125Te Mössbauer spectra of a number of hexahalotellurates have been measured and no significant effects of the size or symmetry of the cation on the Mössbauer parameters were observed. The mixed hexahalotellurates, M2TeX4Y2 (X, Y = Cl, Br, or I), do not exhibit a quadrupole splitting, Δ, and the trends in δ with variation in X and Y are discussed. The pentahalotellurates MTeCl5, MTeBr5, and MTeBr4Cl also yield single line spectra and this is interpreted as evidence of intermolecular bridging. The tetrahaloaryltellurates MArTeX4 and MArTeX3Y (X, Y = Cl, Br, or I) have been studied and the trends in Δ with variation X and Y are consistent with an additive model. The trends in δ are more complex.

scholarly journals Mössbauer Study of Weathered H-meteorite from the Desert of Oman

2020 ◽  
Vol 25 (1) ◽  
pp. 48
Author(s):  
Ahmed D. Al-Rawas ◽  
Abbasher M. Gismelseed ◽  
Subhi Nasir ◽  
Ali A. Yousif ◽  
Mohamed E. Elzain ◽  
...  
Keyword(s):  
Mössbauer Spectra ◽  
57Fe Mössbauer Spectroscopy ◽  
Ordinary Chondrites ◽  
Mössbauer Study ◽  
Magnetic Phases ◽  
Silicate Minerals ◽  
Mossbauer Spectra ◽  
57Fe Mossbauer Spectroscopy ◽  
H Chondrites ◽  
Terrestrial Age

A number of meteorites from the desert of Oman, classified as H-chondrites, with known and unknown ages, were studied by using 57Fe Mössbauer spectroscopy to determine their Fe3+-bearing compositions. Mössbauer spectra measured at 78 K were composed of paramagnetic doublets superimposed on magnetic sextets. The doublets are assigned to the silicate minerals olivine and pyroxene and Fe3+ phases. The magnetic sextets in most samples showed the presence of at least three magnetic phases, namely troilite, magnetite and kamacite, which commonly exist in most ordinary chondrites. The relative amounts (area %) of Fe3+ in the known-age meteorites, determined from the Mössbauer spectra, were plotted against their terrestrial ages. The plot was used to estimate the terrestrial ages of meteorites with unknown terrestrial age.

A Mössbauer Study of the Iron Tetracarbonyl Halides

1973 ◽  
Vol 51 (3) ◽  
pp. 405-410 ◽  
Author(s):  
P. Vasudev ◽  
C. H. W. Jones
Keyword(s):  
Absorption Spectrum ◽  
Mössbauer Spectra ◽  
Mössbauer Study ◽  
Mossbauer Spectra

The 57Fe Mössbauer spectra of the cis-Fe(CO)4X2 compounds (X = Cl, Br, I) have been measured and the values of δ (~0.3 mm s−1) and Δ (~0.3 mm s−1) found to differ significantly from those previously reported for Fe(CO)4I2. The Δ values are analyzed in terms of p.q.s. values of the ligands.The photolysis of cyclohexane solutions of Fe(CO)4I2 was studied and no evidence was found in the 57Fe Mössbauer spectra of frozen samples for the previously proposed formation of trans-Fe(CO)4I2.The 129I Mössbauer absorption spectrum of cis-Fe(CO)4129I2 is reported and the parameters found to be δ = +0.11 ± 0.02 mm s−1, e2qQ = −980 ± 10 Mc s−1, η = 0.00 ± 0.02. The parameters are interpreted as evidence of ca. 5% 5s character on the iodine in the Fe—I bond.

Sign in / Sign up

Export Citation Format

Share Document