[{"from": "human", "value": "Provide a brief overview of this molecule. [C][=C][C][=C][C][=Branch1][Ring2][=C][Ring1][=Branch1][C][=C][C][=C][Ring1][#Branch1][C][=C][C][=C][C][=C][C][=C][Ring1][=Branch1][Ring1][#Branch2]"}, {"from": "gpt", "value": "The molecule is an aromatic hydrocarbon in coal tar, allied to naphthalene and anthracene. It is a white crystalline substance, C18H12, of strong blue fluorescence, but generally colored yellow by impurities."}]