Lanthanum Hexaboride (LaB6, also called lanthanum boride and LaB6) is an inorganic chemical. With a melting point of 2528 K, LaB6 is a refractory ceramic material, which is insoluble in water or hydrochloric acid and very stable in the vacuum. Stoichiometric samples are colored as intense purple-violet, while boron-rich ones (above LaB6.07) are blue. Ion bombardment changes its color from purple to emerald green. LaB6 is a superconductor with a relatively low transition temperature of 0.45 K.