ABSTRACT Melting of orthorhombic boron silicide B6Si has been studied at pressures up to 8 GPa using in situ electrical resistivity measurements and quenching. It has been found that in the 2.6–7.7 GPa range B6Si melts congruently, and the melting curve exhibits negative slope of −31(2) K/GPa that points to a higher density of the melt as compared to the solid phase. At very high temperatures B6Si melt appears to be unstable and undergoes disproportionation into silicon and boron-rich silicides B n Si (n ≥ 12). The onset temperature of disproportionation strongly depends on pressure, and the corresponding low-temperature boundary exhibits negative slope of −92(3) K/GPa which is indicative of significant volume decrease in the course of B6Si melt decomposition.

中文翻译：

---

高压下斜方晶系B6Si的熔融分解

摘要 使用原位电阻率测量和淬火研究了正交晶硅化硼 B6Si 在高达 8 GPa 的压力下的熔化。已经发现，在 2.6-7.7 GPa 范围内，B6Si 完全熔化，熔化曲线呈现负斜率 -31(2) K/GPa，与固相相比，这表明熔体密度更高。在非常高的温度下，B6Si 熔体似乎不稳定并且会歧化成硅和富硼硅化物 B n Si (n ≥ 12)。歧化的开始温度强烈依赖于压力，相应的低温边界呈现负斜率 -92(3) K/GPa，这表明在 B6Si 熔体分解过程中体积显着减少。