CRUSHING C60 TO DIAMOND AT ROOM-TEMPERATURE

C60 MOLECULES are extremely stable, withstanding hydrostatic pressures of up to at least 20 GPa (ref. 1). It has been proposed that at high pressures they could form a solid harder than diamond 2. On the other hand, electrical resistivity measurements 3 have revealed the formation of an insulating phase above 20 GPa, which was attributed to the low-symmetry state found in X-ray diffraction studies under nonhydrostatic compression 1. Here we report that rapid, nonhydrostatic compression of C60 to pressures of 20 +/- 5 GPa transforms it instantaneously into bulk polycrystalline diamond at room temperature. Our measurements place a limit on the stability of the C60 molecular phase under nonhydrostatic pressure. The high efficiency and fast kinetics at room temperature suggest the possibility of using this transformation for fabrication of industrial diamonds.