EXAMPLE: TITLE: PHASE DIAGRAM and ELECTRICAL CONDUCTIVITY of NdBr₃ - KBr
AUTHORS: Madjid Berkani¹, Yassine Bounouri¹, Marcelle Gaune- Escard²
AFFILIATION: ¹Université de Bejaia, Bejaia, Algeria;
²Aix-Marseille Université/Polytech, Marseille, France;

KEYWORDS: Electrical conductivity, NdBr₃-KBr binary system

ABSTRACT
The lanthanide halides and their mixtures with alkali metal halides play a very important role in many modern technologies. They are extensively used in optical and scintillation devices [1] and are attractive components for doses in high-intensity discharge lamps and new highly efficient light sources with energy saving features, lasers, etc. [2] The wide band gap materials like fluorides and other halides co-doped by lanthanide ions provide valuable insight into many aspects of luminescence centers and have wide applications. [3] Such wide applications of these compounds requires knowledge of their structural, physicochemical, and, in particular, their thermodynamic properties. In connection with our research program on lanthanide halides and their systems with alkali metal halides [4], we have investigated the binary system of neodymium(III) bromide with potassium bromide.

The only literature information on this system was the phase diagram reported, as a graphic, by Blachnik and Jaeger-Kasper [5]. The phase equilibrium in the NdBr₃-KBr binary system was established in the present work by differential scanning calorimetry (SETARAM LABSYS evo TG/DSC 1600).

This system includes the K₃NdBr₆, K₂NdBr₅, and KNd₂Br₇ compounds and three eutectics located at the NdBr₃ molar fractions x = 0.192 (T = 849 K), x = 0.532 (T = 754 K) and x = 0.689 (T = 802 K), respectively. K₃NdBr₆ undergoes a solid-solid phase transition at 680 K and melts congruently at 918 K. K₂NdBr₅ melts incongruently at 822 K with the formation of solid K₃NdBr₆ and finally KNd₂Br₇ melts congruently at 814 K.

The electrical conductivity of NdBr₃-KBr liquid mixtures was measured over the whole composition range and a wide temperature range.

REFERENCES:
[1] V.B. Motalov, M.F. Butman, L.S. Kudin, K.W. Kramer, L. Rycerz, M. Gaune-Escard, J. Mol. Liq. 142 (2008) 78-82.
[2] T. Markus, U. Nieman, K. Hilpert, J. Phys. Chem. Solids 66 (2005) 372-375.[3] J. Cybinska, J. Legendziewicz, G. Boulon, A. Bensalah, G. Meyer, Opt. Mater. 28 (2006) 41-52.
[4] I. Chojnacka, L. Rycerz, M. Berkani, M. Gaune-Escard, Journal of Alloys and Compounds 582 (2014) 505-510.
[5] R. Blachnik and A. Jaeger-Kasper, Z. Anorg. Allg. Chem., 461 (1980) 74-86.