Spectral Properties of Marennine-like Pigments Reveal Minor Differences Between Blue Species and Strains.

Marennine is the specific bluish pigment produced by the marine diatom Gaillon (Simonsen), responsible for the greening of oysters in France's Atlantic coast. For decades, was considered the only blue diatom and described as such. However, new blue species have been described recently, among which Davidovich, Gastineau, and Mouget (Black Sea, Crimea, Ukraine); Gastineau, Hansen, and Mouget (Mediterranean Sea, southern France) Gastineau, Hansen, and Mouget (West Atlantic Ocean, USA); and one not characterized yet, sp.

An unusual O/F distribution in the new pyrochlore oxyfluorides: NaBOF (B = Nb, Ta).

Two new oxyfluorides with a pyrochlore-type structure, NaNbOF and NaTaOF, have been obtained, for which the XRD crystallographic study coupled with F solid state NMR reveals an unusual O/F distribution. Both materials are n-type semiconductors exhibiting photoconductive properties.

Towards Reversible High-Voltage Multi-Electron Reactions in Alkali-Ion Batteries Using Vanadium Phosphate Positive Electrode Materials.

Vanadium phosphate positive electrode materials attract great interest in the field of Alkali-ion (Li, Na and K-ion) batteries due to their ability to store several electrons per transition metal. These multi-electron reactions (from V to V) combined with the high voltage of corresponding redox couples (e.g.

Local atomic and electronic structure in the LiVPO (F,O) tavorite-type materials from solid-state NMR combined with DFT calculations.

Li, P, and F solid-state nuclear magnetic resonance (NMR) spectroscopy was used to investigate the local arrangement of oxygen and fluorine in LiVPO F O materials, interesting as positive electrode materials for Li-ion batteries. From the evolution of the 1D spectra versus y, 2D Li radiofrequency-driven recoupling (RFDR) experiments combined, and a tentative signal assignment based on density functional theory (DFT) calculations, it appears that F and O are not randomly dispersed on the bridging X position between two X-VO -X octahedra (X = O or F) but tend to segregate at a local scale. Using DFT calculations, we analyzed the impact of the different local environments on the local electronic structure.

Crystal Structure and Lithium Diffusion Pathways of a Potential Positive Electrode Material for Lithium-Ion Batteries: LiV(HPO).

A new potentially interesting material as a positive electrode for lithium-ion batteries, LiV(HPO), was obtained by hydrothermal synthesis. Its crystal structure was solved thanks to single-crystal X-ray diffraction. This material is isostructural to LiFe(PO)(HPO) and also closely related to LiFe(SO).