Electron paramagnetic resonance of vanadyl ion impurities in crystalline solids

Jain, Vimal K.; Seth, V. P.; Malhotra, Rajesh

doi:10.1016/0022-3697(84)90088-x

Cited by 17 publications

(6 citation statements)

References 47 publications

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“…Then using the values obtained above for the spin-Hamiltonian parameters we estimate that the spin densityx at the vanadium nucleus to take the values 2.82 au and 2.85 au for type I (VO)" in vs and vos respectively. These values are in the range of those reported in the literature for the vanadyl ion [21,22,24].…”

Section: = P B [ G I ( S X B X + S Y B Y ) + G L L S Z B Z I + a ( S...supporting

confidence: 78%

Vanadyl metal mesogen derivatives: an ESR study

Alonso¹,

Sanjuán²,

Romero³

et al. 1990

J. Phys.: Condens. Matter

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An EPR study of the metallo-organic compounds bis [N-pentyl, 4-(4-decyloxybenzoyloxy) salicylaldiminato] of oxovanadium (IV) and bis(N-(4-pentyloxyphenyl), 4-(4-decyloxybenzoyloxy) salicylaldiminato] of oxovanadium (IV) is presented. Both materials are mesogenic and undergo some phase transitions between room temperature and 150 "C (for the first compound) and 270 "C (for the second one). The EPR signals are due to the vanadyl group. The spectra have been measured at different temperatures and the changes in them have been correlated with some of the phase transitions. Modifications in the spectra occurring after several heating-cooling cycles dependent on the presence or absence of an applied magnetic field (up to 1.4 mT) are also observed. The behaviour is discussed in terms of molecular orientations in the presence of a magnetic field. A qualitative discussion of the different contributions to the magnetic susceptibility is given.

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Section: = P B [ G I ( S X B X + S Y B Y ) + G L L S Z B Z I + a ( S...supporting

confidence: 78%

Vanadyl metal mesogen derivatives: an ESR study

Alonso¹,

Sanjuán²,

Romero³

et al. 1990

J. Phys.: Condens. Matter

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“…We tentatively suggest the substitution (A13+-OH -) -(V4+-O2-), where OH is an inner hydroxyl of the octahedral sheet. This substitution, taking into account the radius of the VO 2+ unit of 1.56-1.59 A (Cotton & Wilkinson, 1986;Sharpe, 1992) or 1.67 A (Jain et al, 1984), actually induces a local distortion of the sheet, without drastic charge compensation problems (Fig. 5).…”

Section: And Conclusionmentioning

confidence: 99%

Ferriferous and vanadiferous kaolinites from the hydrothermal alteration halo of the Cigar Lake uranium deposit (Canada)

Mosser¹,

Boudeulle

Weber³

et al. 1996

Clay miner.

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The uranium deposit (1350 Ma) of Cigar Lake (Canada) is surrounded by a late hydrothermal alteration halo (330 Ma) containing Fe-illites and kaolinites. Crystallochemical characterization of the kaolinites has been carried on the microscale using XRD, electron microscopy (SEM and TEM) coupled with EDX spectrometry and EPR. The large, well-crystallized particles show large amounts of Fe (0.9-1.8%) and V (0.3-0.5%). According to EPR measurements performed on both random powders and oriented samples, V occurs as the vanadyl ion VO 2 § in substitution within the octahedral sheet of the kaolinite structure in the same way as Fe 3 § Kaolinite growth proceeded through the hydrothermal alteration of anterior phyllosilicates devoid of V, induced by fluids which leached V-rich titano-magnetites in the surrounding sandstones. RESUME: Le gisement d'uranium (1350 Ma) de Cigar Lake (Canada) pr6sente une aur6ole d'alt6ration hydrothermale (330 Ma) contenant des illites ferrif~res et des kaolinites. Nous avons r6alis6 une 6tude cristallochimique des kaolinites h l'6chelle de la particule en combinant la diffraction des RX, la microscopie 61ectronique (MEB et MET) coupl6e h la spectrom6trie RX en dispersion d'6nergie et la r6sonance paramagn6tique 61ectronique (RPE). Les particules, bien form6es et de haute cristaUinit6, montrent un taux 61ev6 de Fe (0.9-1.8%) mais surtout de V (0.3-0.5%). D' apr~s les donn6es RPE, enregistr6es sur des poudres et des 6chantillons orient6s, le V apparait sous forme d'ions vanadyle VO 2+, en substitution, comme Fe 3 § dans la couche octa~drique de la kaolinite. Le ddveloppement des kaolinites r6sulte de l'alt6ration hydrothermale de phyllosilicates ant6rieurs, d6pourvus de V, par des fluides enrichis en cet 616ment lors du lessivage de titanomagn6tites dans les gr~s environnants.The Canadian uranium deposit at Cigar Lake occurs near the unconformity between the metamorphosed Lower Proterozoic basement and the Middle Proterozoic sedimentary cover. This ore deposit is surrounded by a hydrothermal alteration halo which affects the metamorphosed basement for more than 100 m depth and the Athabasca sandstones for more than 200 m above the unconformity (Fouques et al.,

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“…The crystal structure of K 2 C 2 O 4 •H 2 O has been investigated by Hodgson and Ibers [13] from X-ray diffraction and by Chidambaram et al [10] using neutron diffraction techniques. K 2 C 2 O 4 •H 2 O crystallizes as per the C2/c (C 6 2h ) space group in the monoclinic centrosymmetric lattice and the molecular symmetry of the oxalate group is D 2h . It occupies the C i site in the unit cell while the factor group is C 6 2h .…”

Section: Crystal Structurementioning

confidence: 99%

“…Moreover, we are interested in studying the structural changes using an electron spin resonance technique and also where paramagnetic vanadyl ions act as useful probes for electron paramagnetic resonance (EPR) investigations [2]. Many optical absorption and EPR studies are reported for vanadyl ions doped in a number of host lattices [3][4][5][6][7] and changes in energy levels/parameters are observed from one host to another.…”

Section: Introductionmentioning

confidence: 99%

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Effect of vanadyl doping on relative intensities of factor group split Raman bands in potassium oxalate monohydrate

2019

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We report Raman spectral studies of pure potassium oxalate monohydrate, K 2 C 2 O 4 • H 2 O (POM) and its doped varieties with 1 and 5% vanadyl concentrations at room temperature. Apart from many other interesting changes in the Raman spectra on doping with VO 2+ , one of the most intriguing observations is the change in relative intensities of factor group split components of several Raman bands including some bands in the lattice mode region. We have explained the relative intensity changes of factor group split components in terms of locking of adjacent C 2 O 4 −H 2 O−C 2 O 4 −H 2 O chains due to vanadyl doping in the POM lattice. The reduction in the intensities of water bands on vanadyl doping also supports this view.

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Electron paramagnetic resonance of vanadyl ion impurities in crystalline solids

Cited by 17 publications

References 47 publications

Vanadyl metal mesogen derivatives: an ESR study

Vanadyl metal mesogen derivatives: an ESR study

Ferriferous and vanadiferous kaolinites from the hydrothermal alteration halo of the Cigar Lake uranium deposit (Canada)

Effect of vanadyl doping on relative intensities of factor group split Raman bands in potassium oxalate monohydrate

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