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Astronomers using the Robert C. Byrd Green Bank Telescope found the negatively-charged form of octatetraynyl (C8H-) in a cold interstellar cloud (middle left) and in the gaseous envelope surrounding an old, evolved star (middle right). This is the largest negatively-charged molecule yet found in space. The scientists believe it probably is formed in steps, illustrated here, proceeding downward.

1. A molecule of C2H attaches to a molecule of C6H2, producing a molecule of C8H2 and a hydrogen atom.

2. Radiation (squiggly line) breaks one hydrogen atom from the C8H2, leaving C8H and a hydrogen atom.

3. Finally, an electron attaches itself to the C8H molecule, freeing a burst of radiation (overall glow seen around the molecule) and leaving the negatively-charged ion C8H-.