Description:
<jats:title>Abstract</jats:title><jats:p>The formation of dianions in helium nanodroplets is reported for the first time. The fullerene cluster dianions (C<jats:sub>60</jats:sub>)<jats:sub><jats:italic>n</jats:italic></jats:sub><jats:sup>2−</jats:sup> and (C<jats:sub>70</jats:sub>)<jats:sub><jats:italic>n</jats:italic></jats:sub><jats:sup>2−</jats:sup> were observed by mass spectrometry for <jats:italic>n</jats:italic>≥5 when helium droplets containing the appropriate fullerene were subjected to electron impact at approximately 22 eV. A new mechanism for dianion formation is described, which involves a two‐electron transfer from the metastable He<jats:sup>−</jats:sup> ion. As well as the prospect of studying other dianions at low temperature using helium nanodroplets, this work opens up the possibility of a wider investigation of the chemistry of He<jats:sup>−</jats:sup>, a new electron‐donating reagent.</jats:p>