[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is colorless, odorless gas shipped as a liquefied gas under its vapor pressure. Contact with the liquid can cause frostbite. It is easily ignited. Its vapors are heavier than air and a flame can travel back to the source of leak very easily. This leak can be either a liquid or vapor leak. It can asphyxiate by the displacement of air. Under prolonged exposure to fire or heat the containers may rupture violently and rocket."}, {"from": "gpt", "value": "[C][C][Branch1][C][F][F]"}]