Synthesis of boron suboxide from boron and boric acid under mild pressure and temperature conditions

Abstract

Boron suboxide (B 6O) was synthesized by reacting boron and boric acid (H 3BO 3) at pressures between 1 and 10 GPa, and at temperatures between 1300 and 1400 °C. The B 6O samples prepared were icosahedral with diameters ranging from 20 to 300 nm. Well-crystallized and icosahedral crystals with an average size of ∼100 nm can be obtained at milder reaction conditions (1 GPa and 1300 °C for 2 h) as compared to previous work. The bulk B 6O sample was stable in air at 600 °C and then slowly oxidized up to 1000 °C. The relatively mild synthetic conditions developed in this study provide a more practical synthesis of B 6O, which may potentially be used as a substitute for diamond in industry as a new superhard material.