863 Project [2009AA033101]; "973" Projects [2010CB833102]; NSFC [50972164, 51222210]; CAS project [KJCX2-YW-W26]; 100 Talent Project of the Chinese Academy of Sciences, Program for New Century Excellent Talents in University [NCET-09-0628]; SRF for ROCS, SEM

Superior Electrochemical Performance and Storage Mechanism of Na3V2(PO4)3 Cathode for Room-Temperature Sodium-Ion Batteries

Impedance spectroscopy measurements evidence superionic Li+ mobility (>10−3 S cm−1) at room temperature and fast ionic mobility for Na+ (5 × 10−6 S cm−1) in high entropy oxides, a new family of oxide-based materials with the general formula (MgCoNiCuZn)1−x−yGayAxO (with A = Li, Na, K). Structural investigations indicate that the conduction path probably involves oxygen vacancies.

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Room temperature lithium superionic conductivity in high entropy oxides

Publisher Summary The intensities of intraconfigurational f–f transitions are reviewed in the chapter The chapter presents the transition mechanisms for lanthanide ions—namely, the magnetic dipole transition, the induced electric dipole transition, and the electric quadrupole transition It discusses the way experimental intensities can be determined from the spectra The chapter also focuses on the expression of the dipole strength and the oscillator strength in oriented and in randomly-oriented systems Correction factors for lanthanide ions in a dielectric medium are described in the chapter Although only a few magnetic dipole transitions exist for the trivalent lanthanide ions, magnetic dipole transitions are of interest, because their intensities are in a first approximation independent of the ligand environment and can, thus, be used as intensity standards The intensity of a magnetic dipole transition can be calculated exactly, provided that suitable wavefunctions are available These wavefunctions can be obtained from diagonalization of the energy matrix

Chapter 167 Spectral intensities of f-f transitions

Inorganic framework solids are no longer limited to just the silicates and phosphates. Recent research has revealed that carboxylates, arsenates, sulfates, selenates, selenites, germanates, phosphites can also form such structures. One of the emerging areas combines the rich coordination chemistry of the central metal ions of many of these structures with the flexibility and functionality of the organic linkers to give rise to organic-inorganic hybrid compounds. The compounds of the transition-metals appear to provide many variations arising from their coordination preferences, ligand geometry, and the valence state. In addition, the combination of the magnetic nature of the transition metal center with the channel structure of open frameworks suggests interesting potential applications. In this Review the synthesis, structures and properties of the various transition-metal open-framework compounds are discussed.

Open-framework structures of transition-metal compounds.

The structure of the Nasicon-type phase Li3Ti2(PO4)3, obtained by chemical lithiation of LiTi2(PO4)3, has been characterised using neutron diffraction for the long range structure and 7Li NMR for more local information. The lithium atoms were precisely located from the neutron diffraction data, using nuclear difference Fourier maps. The lithium ions, which were known to be in the large M2 cavity, occupy two M3 and M′3 subsites (distorted tetrahedra) with occupation factors of 2/3 and 1/3, respectively. From these two intermediate sites, it was shown that the diffusion pathway between two M1 sites in these Nasicon-type structures consists of a set of seven face-sharing tetrahedra. A variable temperature 7Li MAS NMR study showed a set of signals due to a distribution of environments for a given Li+ ion, in terms of occupied or vacant M3/M′3 sites in its vicinity. Elevation of the temperature to 353 K leads to a reversible exchange of these signals, due to fast hopping of Li between the two sites within a given M2 cavity.

On the structure of Li3Ti2(PO4)3

Nonlinear optical properties of some tellurium (IV) oxide glasses

Determination of Local Geometries around Tellurium in TeO2–Nb2O5and TeO2–Al2O3Oxide Glasses by XANES and EXAFS: Investigation of Electronic Properties of Evidenced Oxygen Clusters byAb InitioCalculations

The study of sodium borate glasses over the compositional range 10–35 mol.% Na2O by using Pb2+, Eu3+ and Nd3+ as local sounds shows the existence of two possible situations depending on whether the Na2O content is lower or higher than about 25 mol.%. In the first composition range the simultaneous increase of optical basicity and of modifier ion site asymmetry implies rather a 2D-character of the network former. The properties of the glasses with high Na2O content involve more 3D-character for the former sublattice.

A structural interpretation of the Pb2+, Eu3+ and Nd3+ optical spectra in doped sodium borate glasses

A modified Mach–Zehnder interferometer has been built for measurement of nonlinear-optical susceptibilities in bulk materials. Both slow- and fast-intensity-dependent refractive-index changes can be measured in absolute value, with femtosecond time resolution, high sensitivity, and precision, by means of a new fringe-locking technique. Results on fast nonlinearities of CS2 liquid and glasses are presented.

Time-resolved absolute interferometric measurement of third-order nonlinear-optical susceptibilities

Les composes K3VO4, K3CrO4 et K3MnO4 existent sous deux formes allotropiques isotypes respectivement de K3Cr(O2)4 et de Na2CaSiO4. Des mesures magnetiques confirment le degre d'oxydation +V du chrome et du manganese.



Darstellung und kristallographische und magnetische Eigenschaften der Phasen K3XO4 (XV, Cr, Mn)



Die Verbindungen K3VO4, K2CrO4 und K3MnO4 treten in zwei Formen auf, isotyp mit K3Cr(O2)4 und Na2CaSiO4. Magnetische Messungen bestatigen die Oxydationsstufe +V von Chrom und Mangan.



Preparation and Crystallographic and Magnetic Properties of the Phases K3XO4 (XV, Cr, Mn)



The compounds K3VO4, K3CrO4 and K3MnO4 occur with two allotropic forms, which are isostructural with K3Cr(O2)4 and Na2CaSiO4. Magnetic measurements confirm the oxidation state +V for both chromium and manganese.

R. Olazcuaga

Papers

Nonlinear optical properties of some tellurium (IV) oxide glasses

Determination of Local Geometries around Tellurium in TeO2–Nb2O5and TeO2–Al2O3Oxide Glasses by XANES and EXAFS: Investigation of Electronic Properties of Evidenced Oxygen Clusters byAb InitioCalculations

A structural interpretation of the Pb2+, Eu3+ and Nd3+ optical spectra in doped sodium borate glasses

Time-resolved absolute interferometric measurement of third-order nonlinear-optical susceptibilities

Préparation, Proprietés Cristallographiques et Magnétiques des Phases K3XO4 (XV, Cr, Mn)