Benzonitrile (c-C₆H₅CN, where ‘c’ indicates a cyclic structure), a polar proxy for benzene (c-C₆H₆), has the potential to serve as a highly convenient radio probe for aromatic chemistry, provided that this ring can be found in other astronomical sources beyond the molecule-rich prestellar cloud TMC-1. Here we present radio astronomical evidence of benzonitrile in four other prestellar, and possibly protostellar, sources: Serpens 1A, Serpens 1B, Serpens 2 and MC27/L1521F. These detections establish that benzonitrile is not unique to TMC-1; rather, aromatic chemistry appears to be widespread throughout the earliest stages of star formation, probably persisting at least until the initial formation of a protostar. The abundance of benzonitrile far exceeds predictions from models that well reproduce the abundances of carbon chains such as HC₇N, a cyanpolyyne with the same heavy atoms, indicating that the chemistry responsible for planar carbon structures (as opposed to linear ones) in primordial sources is favourable but not well understood. The abundance of benzonitrile relative to carbon chain molecules displays sizable variations between sources within the Taurus and Serpens clouds, implying the importance of physical conditions and initial elemental reservoirs of the clouds themselves.

苯甲腈（cC ₆ H ₅ CN，其中“c”表示环状结构），苯的极性代表物（cC ₆ H ₆)，有可能成为芳香化学的一种非常方便的无线电探测器，前提是这个环可以在除富含分子的星前云 TMC-1 之外的其他天文来源中找到。在这里，我们展示了苯腈在其他四个前恒星（可能是原恒星）来源中的射电天文证据：Serpens 1A、Serpens 1B、Serpens 2 和 MC27/L1521F。这些检测表明苯甲腈不是 TMC-1 独有的；相反，芳香化学似乎在恒星形成的最初阶段广泛存在，可能至少持续到原恒星最初形成。苯甲腈的丰度远远超过模型的预测，这些模型很好地再现了 HC _{7等碳链的丰度}N，具有相同重原子的氰基多炔，表明在原始来源中负责平面碳结构（与线性碳结构相反）的化学性质是有利的，但尚未得到很好的理解。相对于碳链分子而言，苯甲腈的丰度在金牛座和巨蛇云内的来源之间显示出相当大的差异，这意味着物理条件和云本身的初始元素储层的重要性。