A low-temperature route for the synthesis of nanocrystalline LaB6

Nanocrystalline lanthanum hexaboride (LaB6) with mean particle size of 30 nm has been successfully synthesized at 400 °C in an autoclave starting from metallic magnesium powder, NaBH4 and LaCl3. In this case, by using B2O3 instead of NaBH4, LaB6 nanocubes with mean size of ∼200 nm were formed at 500 °C. The X-ray diffraction (XRD) pattern can be indexed as cubic LaB6 with the lattice constant of a=4.151 Å for LaB6 nanoparticles and 4.154 Å for LaB6 nanocubes. An atomic ratio of La and B as 1:5.94 was determined from EDS for LaB6 nanoparticles. XPS data of LaB6 nanocubes indicate the atomic ratio of La to B as 1:5.95. Raman spectra indicate the formation of LaB6.