Isothermal equations of state were determined for the open-framework silicon allotrope ${\mathrm{Si}}_{24}$ and its sodium-filled precursor $\left({\mathrm{Na}}_4{\mathrm{Si}}_{24}\right)$ using different pressure media including hydrogen and argon, and with no pressure medium. ${\mathrm{Si}}_{24}$ does not transform into diamond-cubic silicon under compression, and the low-density phase possesses a bulk modulus of 91(2) GPa. The sodium-filled precursor exhibits a comparable volumetric compressibility with different axial trends that are explained by the crystallographic structure. Above 11 GPa, ${\mathrm{Si}}_{24}$ transforms to the β-tin structure, followed by other high-pressure silicon allotropes similar to diamond-cubic silicon, driven by a large increase in density. Small molecules such as ${\mathrm{H}}_2$ do not enter the channels of ${\mathrm{Si}}_{24}$ during compression at room temperature, however, hydrostaticity strongly influences the transformation pressure and range of coexistence with other phases including β-Sn, $Imma$, and simple-hexagonal Si.

中文翻译：

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准静水和非静水条件下充满钠的空的开放骨架Si24的压缩

确定了开放骨架硅同素异形体的等温状态方程 ${硅}_{24}$ 及其钠填充前体 $（{娜}_4{硅}_{24}）$ 使用包括氢气和氩气在内的不同压力介质，并且没有压力介质。 ${硅}_{24}$在压缩下不会转变成金刚石立方硅，并且低密度相的体积模量为91（2）GPa。钠填充的前体表现出相当的体积可压缩性，具有不同的轴向趋势，这由晶体结构解释。高于11 GPa，${硅}_{24}$转变为β-锡结构，然后是其他密度与金刚石立方晶硅相似的高压硅同素异形体，这是由于密度的大幅提高所致。小分子如${\mathrm{H}}_2$ 不要进入 ${硅}_{24}$ 但是，在室温下压缩时，静水压会强烈影响相变压力和与其他相（包括β-Sn， $\mathrm{一世}米米\mathrm{一种}$，和简单的六边形Si。