Abstract: It is believed that it is difficult to synthesize cyclopentadienyl light RE chloride from tri-cyclopentadienide compounds of RE because of disproportionation reaction which is related to lanthanide contraction and coordination unsaturation. In this work, the dinuclear organic compounds of RE-lithium were synthesized using THF solution of LnCl₃·nLiCl.The disproportionation reaction is considered to be avoided by the stable effect of chloro-bridge link. Mono-cyclopentadienyl light RE chlorides were synthesized from tri-cyclopentadienide compounds of RE successfully.

Key words: Mono-cyclopentadienyl, light RE chlorides, Tri-cyclopentadienide, Disproportionation reaction