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This article mentions “ferricyanide, an electron-hungry molecule.” This puzzled me no end. Aren’t ferricyanide molecules, unlike their ions, electrically neutral? I’m trying to visualize ravenous molecules gobbling up innocent electrons.

Ernest Nussbaum
Bethesda, Md.

Ferricyanide is indeed an ion, with a negative charge of –3. It’s electron hungry because, counterintuitively, it draws an electron from the carbon nanotube to become ferrocyanide (charge of –4). The reaction tends in that direction because ferrocyanide is more stable thermodynamically than ferricyanide is .—A. Goho