[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is a bis(eta(5)-cyclopentadienyl)metal(II) having Zr(II) as the metal(II) species. The parent of the class of zirconocenes. It is a member of zirconocenes and a bis(eta(5)-cyclopentadienyl)metal(II)."}, {"from": "gpt", "value": "[CH1-1][CH1-1][CH1-1][CH1-1][CH1-1][Ring1][Branch1].[CH1-1][C][=C][C][=C][Ring1][Branch1].[Zr]"}]