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

We report the mechanically induced chemical decomposition of C60-n-pen tane. This material is a typical C60 clathrate with a well-characteriz ed structure and is stable up to 400 K. However, at room temperature t he grinding of C60-n-pentane induces the loss of n-pentane from the or iginally orthorhombic structure and the material transforms to pure C6 0 with the face-centered-cubic structure. The average crystallite size of the final powder is quite small, from x-ray powder diffraction pea k widths it is estimated to be 150 angstrom. This unusual chemical dec omposition at room temperature points to the highly strained nature of the structure. Similar chemical decomposition might exist for other C 60 clathrates such as C60 acetone.