[{"from": "human", "value": "Could you give me a brief overview of this molecule? [C][=O]"}, {"from": "gpt", "value": "The molecule appears as a colorless liquid with a pungent irritating odor. Contains 37-50% formaldehyde by mass and varying amounts of methanol, added to prevent precipitation of formaldehyde polymers (formaldehyde exists in solution as CH2(OH)2 and its polymers HO(CH2O)xH where x averages about three). Formalin free of methanol is also shipped but must be kept warm (about 30 \u00b0C (86 \u00b0F)) to prevent polymerization. Pure formaldehyde, a gas, is not handled commercially because it tends to polymerize exothermally and may ignite. Vapor from formalin solution is flammable and an explosion hazard when exposed to flame or heat. Skin and eye irritant. Confirmed carcinogen."}]