Letters from the February 19, 2005, issue of Science News
By Science News
Negative thinking
The article “Sweet Glow: Nanotube sensor brightens path to glucose detection” (SN: 1/1/05, p. 3) 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