Titan, the largest satellite of Saturn, possesses a complex photochemical cycle producing a broad inventory of organic molecules in its thick atmosphere and on its surface. Two of the most common molecules in this inventory include acetylene (C₂H₂) and acetonitrile (CH₃CN). We have previously demonstrated that certain organic molecules (such as benzene and ethane) readily form co-crystals under Titan-relevant conditions. Here, we report Raman spectroscopic and X-ray diffraction evidence for a co-crystal between acetonitrile and acetylene at Titan surface conditions. This molecular mineral could be relatively abundant on Titan, in particular in the large fluvially dissected plateaux of labyrinth terrains and possibly the undifferentiated plains, which are believed to be the end-stage product of the labyrinth terrains. Co-crystals might provide a mechanism for storing energy-rich molecules such as acetylene, permitting sequestration and transport to the subsurface where these deposits could be accessed by putative life.

中文翻译：

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泰坦表面条件下乙腈-乙炔共晶的性质和行为

土星最大的卫星土卫六拥有复杂的光化学循环，在其浓厚的大气层及其表面上会产生大量的有机分子。此清单中最常见的两个分子包括乙炔（C ₂ H ₂）和乙腈（CH ₃CN）。先前我们已经证明，某些有机分子（例如苯和乙烷）在与泰坦有关的条件下很容易形成共晶体。在这里，我们报告了泰坦表面条件下乙腈和乙炔之间共晶体的拉曼光谱和X射线衍射证据。这种分子矿物质在土卫六上可能相对丰富，特别是在迷宫地形的大型河流平地，可能还有未分化的平原上，据信这是迷宫地形的最终产物。共晶可能提供了一种用于存储能量丰富的分子（例如乙炔）的机制，从而可以螯合并运输到地下，在这些地下可以通过假定的生命来访问这些沉积物。