ChemInform Abstract: INFRARED SPECTROMETRIC AND EPR STUDY ON COPPER CHROMATE AND COPPER CHROMITE

Arsène, J.; Lenglet, M.; Erb, A.; Granger, Pascal

doi:10.1002/chin.197905014

Cited by 3 publications

(3 citation statements)

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“…In the case of tetragonal spinel Li 2 Mn 2 O 4 compound, four phonon lines can be detected in the frequency range 200-650 cm Ϫ1 as for the cubic spinel phase, even though a lowering of crystal symmetry from Fd3m to I4 1 /amd increases the number of Raman active modes. 23 In addition, these spectral features of the tetragonal spinel are found to be more intense and sharper than those of the cubic one, which can be explained by a decrease of electrical conductivity leading to an enhancement of the optical skin depth of the incident laser beam.…”

Section: Resultsmentioning

confidence: 95%

Micro-Raman Spectroscopic Study on Layered Lithium Manganese Oxide and Its Delithiated/Relithiated Derivatives

Hwang

Park

Choy

et al. 2001

Electrochem. Solid-State Lett.

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Micro-Raman spectroscopic analyses have been performed for the layered LiMnO 2 compound and its delithiated/relithiated derivatives in order to probe the effect of Li extraction/insertion on the local structure around manganese ion in this layered material. For this purpose, we have first tried to establish a spectroscopic measure for identifying the lithium manganates with closely related structures. From the detailed comparison among the Raman spectra of layered and spinel-structured lithium manganates, both phases can be easily differentiated from each other by using micro-Raman spectroscopy. Based on these experimental findings, we are able to conclude that the chemical or electrochemical deintercalation of lithium gives rise to the Mn migration into the interlayer lithium site, resulting in the creation of the spinel-like cation ordering.Recently, lithium manganese oxides have received considerable attention as promising cathode materials in lithium secondary batteries, since manganese is more abundant, less expensive, and less toxic than cobalt used in the currently commercialized lithium rechargeable batteries. 1-3 For this reason, intense research efforts have been directed not only to develop new types of manganese-based compounds but also to improve the electrochemical performance of existing lithium manganate cathode materials. Although the spinel LiMn 2 O 4 is the most widely studied among the lithium manganate systems, there is increasing interest in other types of lithium manganese oxides such as layered LiMnO 2 , orthorhombic LiMnO 2 , nanocrystalline manganese oxyiodides, etc. 4-8 Among them, the layered LiMnO 2 exhibits the largest initial capacity for the 4 V region but it suffers from severe capacity fading after the first charge process. 4 Such a remarkable capacity loss would be attributed to the destabilization of layered structure induced by the electrochemical delithiation reaction. 9,10 In fact, most manganese oxides have been known to experience such a structural modification during extended electrochemical charge/discharge cycling. 11,12 Since the local atomic arrangement of the cathode material is closely related to its electrochemical performance, neutron and X-ray diffraction ͑XRD͒ analyses were performed to investigate the variation of the crystal structure of lithium manganese oxides during electrochemical cycling. 13,14 Although these diffraction methods have been reported to be useful in probing the average structure of electrode material, they cannot provide detailed information on the local structure around manganese ion. As an alternative tool, vibrational spectroscopy allows us to examine the local crystal structure of cathode materials including the electrochemically cycled derivative with poor crystallinity, since it does not need long range structural order. 15-20 Moreover, taking into account the fact that the vibrational spectrum is very sensitive to the crystal symmetry, this kind of spectroscopic method should be effective in differentiating various kinds of lithium ma...

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Section: Resultsmentioning

confidence: 95%

Micro-Raman Spectroscopic Study on Layered Lithium Manganese Oxide and Its Delithiated/Relithiated Derivatives

Hwang

Park

Choy

et al. 2001

Electrochem. Solid-State Lett.

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“…A polycrystalline sample of CuCrO 4 was prepared by separately dissolving equimolar amounts of anhydrous Copper(II)acetate and Chromium(VI)oxide in distilled water, similar to the recipe given by Arsene et al 38 . The two solutions were mixed and boiled to dryness.…”

Section: Methodsmentioning

confidence: 99%

Quasi-one-dimensional antiferromagnetism and multiferroicity in CuCrO4

et al. 2011

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The bulk magnetic properties of the new quasi-one-dimensional Heisenberg antiferromagnet, CuCrO4, were characterized by magnetic susceptibility, heat capacity, optical spectroscopy, EPR and dielectric capacitance measurements and density functional evaluations of the intra-and inter-chain spin exchange interactions. We found type-II multiferroicity below the Néel temperature of 8.2(5) K, arising from competing antiferromagnetic nearest-neighbor (Jnn) and next-nearest-neighbor (Jnnn) intra-chain spin exchange interactions. Experimental and theoretical results indicate that the ratio Jnn/Jnnn is close to 2, putting CuCrO4 in the vicinity of the Majumdar-Ghosh point.

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“…In the case of CuCrO 4 , only ESR measurements were performed. The spectra only show a very broad signal with a mean g-value of 2.16 and a band width of around 650 G [166] (see also [119]).…”

Section: Chromatesmentioning

confidence: 99%

Materials belonging to the CrVO4 structure type: preparation, crystal chemistry and physicochemical properties

Baran

1998

Journal of Materials Science

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Crystallographic data of vanadates, phosphates, chromates, sulphates and selenates belonging to the CrVO 4 (b-CrPO 4 ) structure type and of some of its most important polymorphs, are reported. Characteristic structural peculiarities and the effect of pressure on the phase transformations are discussed. A definitive stability field for this structure type could be established. Synthetic procedures for the preparation of the different compounds adopting this and closely related structures are presented and its thermal, spectroscopic and magnetic properties are discussed. A brief overview on the most important characteristics of materials adopting the a-CrPO 4 structure is also presented.

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ChemInform Abstract: INFRARED SPECTROMETRIC AND EPR STUDY ON COPPER CHROMATE AND COPPER CHROMITE

Abstract: CuCrO4 und praktisch chromatfreies CuCr2O4 werden durch Reaktion zwischen Cu(OH)2 und CrO3 bei 100°C bzw. durch Glühen von Cr2O3 und CuO bei 800‐850°C (6‐8 Wochen) dargestellt und thermogravimetrisch, röntgenographisch, IR‐ sowie EPR‐spektroskopisch untersucht.

Cited by 3 publications

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Micro-Raman Spectroscopic Study on Layered Lithium Manganese Oxide and Its Delithiated/Relithiated Derivatives

Micro-Raman Spectroscopic Study on Layered Lithium Manganese Oxide and Its Delithiated/Relithiated Derivatives

Quasi-one-dimensional antiferromagnetism and multiferroicity in CuCrO4

Materials belonging to the CrVO4 structure type: preparation, crystal chemistry and physicochemical properties

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