Chemists in Germany have measured the strength of a chemical bond directly
for the first time by staging a molecular tug of war.
Hermann Gaub and his colleagues at the Ludwig-Maximilian University in Munich
stretched a single polymer strand between a glass surface and the tip of an
atomic force microscope. By gradually moving the tip away from the surface, the
researchers found that it took 2 nanonewtons to wrench carbon from silicon
(Science,vol 283, p 1727).