Project Details Mutual Solubility of Rare Earth Metal (Sc, Y, Lanthanides) Bromides in Molten Alkali Bromides

Project No.:
Start Date:
01 September 2013
End Date:


Series: Solubility Data Series

This project will compile and evaluate all available solubility data of rare earth metal bromides in molten alkali bromides.

Indeed, the versatility and specificity of the rare earth elements (REE) has given them a level of technological, environmental and economic importance, considerably greater than might be expected from their relative obscurity. They are used: for glasses (polishing compounds, UV resistant glass), ceramics (sensors, scintillators), metallurgical alloys (NiMH batteries, lighter flints, super alloys), magnets (motors, disc drivers, speakers) and phosphors (fluorescent lightning, lasers, LCD). A lot of applications are found in medicine (contrast agent, MRI, PET), in electronics (semiconductors, cathodes, capacitors) and in automotive (catalytic converter, fuel cells). REE can be used in nuclear industry, as hydrogen fuel storage, in sonar systems, in photography and also in trichromatic fluorescent lamps. This growing importance of REE in people’s everyday living requires searching, finding and characterizing the basic thermodynamic properties of new compounds containing lanthanides.

Since several years we have initiated an extensive experimental research program focused on thermodynamic properties, structural and electrical conductivity of the LnX3-MX systems (Ln=lanthanide, X=halide, M=akali) together with phase equilibrium calculations and data mining techniques having predictive capabilities.

The present project will focus and assess all available solubility data of rare earth metal bromides in molten alkali bromides. This will constitute the first phase of a larger project that will include the same approach on other lanthanide halides melts at large.


A complete set of compilations will be prepared for the solubility of all rare earth metal bromides in molten alkali bromides. The set of compilations related to a selected metal will be introduced with a critical evaluation of all related solubility results, equilibrium solid phases and a selection of suggested solubility data. Lanthanide halides are used in a number of applications ranging from lighting to catalysis through pyrochemical reprocessing of nuclear fuel or new scintillation materials. Much has been done to achieve fundamental insight that is required by those many industrial processes still under development. The mutual solubility of molten lanthanide bromides (LnBr3) and alkali bromides (MBr) has been investigated intensively over the past two decades.


Dec 2018 update – All experimentally determined solubility data of the molten rare earth metal bromides in molten alkali bromide systems have been collected from original data sources. Data were tabulated and a critical evaluation of all related solubility results and equilibrium solid phases was performed, resulting in a selection of suggested solubility data. For each system, additional information on the method, apparatus and procedure was also provided in order to support the data selection or recommendation as best data. The collected data are being processed as a volume of the Solubility Data Series according to the guidelines in Pure Appl. Chem., Vol. 82, No. 5, pp. 1137–1159, 2010 (, for preparation and use of compilations and evaluations.

Feb 2021 update – A revised draft has been prepared and is being checked.

Last update: 14 Apr 2021