Octatetraynyl radical

Octatetraynyl radical (C8H) is an organic free radical with eight carbon atoms linked in a linear chain with alternating single bonds and triple bonds (H\sC\tC\sC\tC\sC\tC\sC\tC•).

In 2007 negatively charged octatetraynyl was detected in Galactic molecular source TMC-1, making it the second type of anion to be found in the interstellar medium (after hexatriynyl radical) and the largest such molecule detected to date.