Barium hexaboride is a hard, black crystalline compound with a high melting point.
Synthesis It can be synthesized by passing barium vapour over boron crystals at >:
It can also be synthesized by reacting barium chloride with boron in two stages: firstly at for 30 minutes and then at for 60 minutes.
Potential applications Barium hexaboride has been considered as a candidate for use in hot-cathode electron guns.
References
Further reading An analysis of the fine structure of :