You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
diiodoytterbium;1,2,3,4,5-pentamethylcyclopenta-1,3-diene;1,2,3,4,5-pentamethylcyclopentane is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H30I2Yb-6
assistant