[{"from": "human", "value": "Could you provide a description of this molecule? [C][C][=Branch1][C][=O][C][Br]"}, {"from": "gpt", "value": "The molecule is an alpha-bromoketone that is acetone in which one of the hydrogens is replaced by a bromine atom. A poweful lachrymator, it was formerly used as a chemical weapon. It has a role as a lachrymator. It is functionally related to an acetone."}]