Wikipedia
Cyclopentadienylthallium
Cyclopentadienylthallium, also known as thallium cyclopentadienide, is an organothallium compound with formula CHTl. This light yellow solid is insoluble in most organic solvents, but sublimes readily. It is used as a precursor to transition metal and main group cyclopentadienyl complexes, as well as organic cyclopentadiene derivatives.