The oxidation state of europium in halide glasses

Abstract

The luminescent properties of divalent europium ions can be exploited to produce storage phosphors for x-ray imaging applications. The relatively high cost and limited availability of divalent europium halides makes it desirable to synthesize them from the readily available trivalent salts. In this work, samples of pure EuCl3 and fluoride glass melts doped with EuCl3 were processed at 700-800 °C in an inert atmosphere furnace. The Eu oxidation state in the resulting materials was determined using fluorescence and Mössbauer spectroscopy. Heat treatment of pure EuCl3 for 10 minutes at 710 °C resulted in a material comprising approximately equal amounts of Eu2+ and Eu3+. Glasses made using mixtures of EuCl2 and EuCl3 in the starting material contained both oxidation states. This paper describes the sample preparation and analysis and discusses the results in the context of chemical equilibria in the melts.

Characterization of Luminescent Materials with 151Eu Mössbauer Spectroscopy

“…Weber et al [91] showed that EuCl${}_3$ heated at 710 ${}^{\circ }$C for 10 min resulted in almost equal amounts of EuCl${}_2$ and EuCl${}_3$. This could be important for production of EuCl${}_2$ storage phosphors since EuCl${}_2$ is more expensive than EuCl${}_3$.…”

“…Mössbauer spectra of ZBLAN samples made with ( a ) 5.0 mol % EuCl${}_2$; and ( b ) 2.5 mol % EuCl${}_2$ and 2.5 mol % EuCl${}_3$ [91]. The solid lines represent a fit of the Mössbauer spectra using simple Lorentzian functions.…”

Opportunities for Fluorochlorozirconate and Other Glass-Ceramic Detectors in Medical Imaging Devices

“…Neither oxide nor oxyfluoride medical imaging plates have been developed, so far, but could possibly be in the future. Fluoride glass ceramics have shown great potential as x-ray image plates [6–13]. The development of new glass-ceramic materials is currently a busy field, especially in the sol-gel area due to the room temperature options for synthesis and ability to produce uniform dispersion of nanoparticles.…”

Crystallization studies on rare-earth co-doped fluorozirconate-based glasses

“…At this moment, several routes are being explored to reduce costs of Eu 2+ -doped glasses and to achieve a higher total luminescence output [9, 10]. It was shown that during glass melting cheaper Eu 3+ is partially reduced to the more expensive Eu 2+ , meaning that multivalent doping of Eu 2+ and Eu 3+ in the starting materials can reduce costs.…”