MECHANICALLY INDUCED CHEMICAL DECOMPOSITION OF C-60-N-PENTANE CLATHRATE AT ROOM-TEMPERATURE

We report the mechanically induced chemical decomposition of C60-n-pentane. This material is a typical C60 clathrate with a well-characterized structure and is stable up to 400 K. However, at room temperature the grinding of C60-n-pentane induces the loss of n-pentane from the originally orthorhombic structure and the material transforms to pure C60 with the face-centered-cubic structure. The average crystallite size of the final powder is quite small, from x-ray powder diffraction peak widths it is estimated to be 150 angstrom. This unusual chemical decomposition at room temperature points to the highly strained nature of the structure. Similar chemical decomposition might exist for other C60 clathrates such as C60 acetone.