A. Wheeler. Chemical Formula = 4,5,6,8-(C₆H₅)4-1,4,5,7,8-(eta-C₅H₅)Co(C₄B₃H₃)

Cobalt is central between two (almost) parallel sets of five-membered atoms; (a) a cyclopentadienyl anion ring, and (b) three C atoms plus 2 B atoms from a polyhedral cluster. An example of a "sandwich" compound.