You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
cyclopenta-2,4-dien-1-ylcycloheptane;1,2,3,5-tetramethylcyclopenta-1,3-diene;zirconium(4+);dichloride The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H30Cl2Zr
assistant