SUPERCONDUCTIVITY AND SITE-SELECTIVE INTERCALATION IN KRBCSC60

Ternary-alkali-metal-intercalated fullerides, KRbCsC60, was prepared b y method employing alkali metal azides reported by Bensebaa et al. (F. Bensebaa, B. Xiang and L. Kevan: J. Phys. Chem. 96 (1992) 6118). We f ound that KRbCsC60 is a superconductor with the transitipn temperature of 28(bulk) approximately 29 K (onset). It was also found, from nucle ar magnetic resonance (NMR) study of Rb-87 and Cs-133 in this system, that the alkali atoms are site-selectively intercalated into C60 face- centered-cubic (fcc) lattice. The largest alkali-metal ion, Cs, occupi es octahedral sites of the C60 fcc lattice, and the K and Rb atoms occ upy mainly tetrahedral sites.