Wikipedia
An actinocene is a type of metallocene compound that contains an element from the actinide series. The typical structure is a sandwich compound, with two cyclooctatetraenyl di anions (cot, which is ) bound to an actinide-metal center (An) in the oxidation state IV, with the resulting general formula An(CH)
The most studied actinocene is uranocene, U(CH).
The actinide-cyclooctatetraenyl bonding was shown by computational chemistry to be mainly due to mixing of actinide 6d orbitals into ligand π- orbitals and therefore donation of electronic charge to the actinide, with a smaller such interaction involving the actinide 5f orbitals.
Other actinocenes include protactinocene (Pa(CH)), thorocene (Th(CH)), neptunocene (Np(CH)), and plutonocene (Pu(CH)).
Sandwiched M(CH) compounds (actinocenes and lanthanocenes) exist for M = ( Nd, Tb, Pu, Pa, Np, Th, U and Yb).