Supramolecular architecture of [AsPh2Br2]2[(Br3)−…(Br2)…(Br3)−] obtained by bromination of (AsPh2)2S

Bromination of (AsPh2)2S leads to cleavage of the sulfide bridge to give AsPh2Br when 1 mol of bromine is used but with 2 mols the product is the polybromide, [AsPh2Br2]2[Br8], containing the previously unknown [AsPh2Br2]+ cation and a rare [(Br3)−…(Br2)…(Br3)−] ensemble whose short (yet not covalent) Br2…Br3 contacts have previously supported tentative description as an octabromide Br82− anion. X-ray crystallography shows that the compound has a three dimensional supramolecular structure based on cooperativity of weak intermolecular Csingle bondH…π, Csingle bondH…Br hydrogen bonds and secondary Br…Br interactions in the solid state. The electronic structure and the stability of the [AsPh2Br2]2[Br8] are rationalized using DFT and HF calculations and molecular orbital considerations

Preferential site substitution of Eu3+ ions in Ca10(PO4)6Cl2 nanoparticles obtained using microwave stimulated wet chemistry technique.

International audienceThe Eu3+ doped Ca10(PO4)6Cl2 nanocrystalline powders were synthesized using a microwave stimulated technique. Additional post heat treatment in the temperature range 800–1100 °C was applied in order to improve the crystallinity of the final product and eliminate the residual amorphous phase. Detailed structural characterization was performed by X-ray diffraction (XRD), Raman and infrared (IR) spectroscopy, transmission electron microscopy (TEM) and X-ray fluorescence (EDX). The optical properties of the Ca10(PO4)6Cl2 samples doped with different Eu3+ concentrations (0.5–5 mol%) were determined by measuring excitation, emission spectra and luminescence. TEM images confirmed the nanoscale nature of the final product with a primary particle size of about 60 nm and a hydrodynamic size of 200 nm when the product was dispersed in Milli-Q purified water (MQ) without further stabilization. The analysis of the 5D0 → 7F0 transition points out that for low concentration Ca(II) (A) site is preferentially substituted whereas increase of Eu3+ above 2 mol% results in domination of the Eu3+ cations located at Ca(I) (B) site. Increase of annealing temperature leads to an increase of the 5D0 → 7F0 intensity associated with the Eu3+ at A site. Preferential site substitution can be solved by analysis of the optical properties of the Eu3+ ion. The Judd–Ofelt parameters were calculated using simplified formalisms. The mechanism of concentration quenching process was identified as a dipole–dipole interaction

World production and possible recovery of cobalt from the Kupferschiefer stratiform copper ore

Cobalt is recognized as a strategic metal and also E-tech element, which is crucial for worlds development. An increasing demand for cobalt forces for searching of new resources that could be explored in European countries. There are many examples of cobalt recoveries, mostly from laterite and sulphide deposits. However, the accurate choice of the technology depends on many factors. The Kupferschiefer stratiform copper ore located in Poland is the biggest deposit of cobalt in Europe. Although KGHM Polska Miedz S.A. recovers many precious metals from this ore, cobalt is not recovered yet. This metal occurs as an accompanying element, mostly in the form of cobaltite (CaAsS), with the average content of 50–80 g/Mg. In this paper a possible recovery of cobalt from the Kupferschiefer ore, with the use of hydrometallurgical methods, was investigated

World production and possible recovery of cobalt from the Kupferschiefer stratiform copper ore

Cobalt is recognized as a strategic metal and also E-tech element, which is crucial for worlds development. An increasing demand for cobalt forces for searching of new resources that could be explored in European countries. There are many examples of cobalt recoveries, mostly from laterite and sulphide deposits. However, the accurate choice of the technology depends on many factors. The Kupferschiefer stratiform copper ore located in Poland is the biggest deposit of cobalt in Europe. Although KGHM Polska Miedz S.A. recovers many precious metals from this ore, cobalt is not recovered yet. This metal occurs as an accompanying element, mostly in the form of cobaltite (CaAsS), with the average content of 50–80 g/Mg. In this paper a possible recovery of cobalt from the Kupferschiefer ore, with the use of hydrometallurgical methods, was investigated