Study by X-ray diffraction and Raman spectroscopy of a Dy@C <InlineEquation ID="Equ1"> <EquationSource Format="TEX">$_{\mathsf{82}}$</EquationSource> </InlineEquation> single crystal

We report the first X-ray diffraction and Raman spectroscopy study of a single crystal of the rare-earth endohedral fullerene Dy@C<Subscript>82</Subscript>. The lattice is found to be body-centered cubic (a=25.79 Å, space group <InlineEquation ID="Equ2"> <EquationSource Format="TEX">$I\bar {4}3d)$</EquationSource> </InlineEquation> which is at variance with previous reports and confirms that several types of structures can be stabilized in Dy@C<Subscript>82</Subscript>. X-ray diffraction/diffuse scattering methods reveal no low-temperature change down to 12 K for the present structure. The Raman spectroscopy data are comparable to those of other M@C<Subscript>82</Subscript> endohedral compounds. However, the Dy oxidation state and the force constant of the low-frequency metal-cage stretching mode do not follow the simple relationship observed before. Copyright Springer-Verlag Berlin/Heidelberg 2003