Lanthanum hexaboride (LaB6) nanoparticles were successfully synthesized via the reaction of lanthanum trichloride (LaCl3) and sodium borohydride (NaBH4) in a molten KCl/LiCl eutectic salt. The changes in the phase composition and morphology of LaB6 as a function of temperature were systemically investigated. By increasing the temperature from 600 degrees C to 800 degrees C, the crystallinity of LaB6 particles increased and the sphere-like morphology of 49.0 nm changed to the cubic shape of 94.7 nm. Additionally, the microstructure and chemical composition of LaB6 nanocubes were further characterized, and the possible synthesis mechanism of LaB6 nano-particles was proposed based on the experimental results. (C) 2017 Published by Elsevier B.V.