[{"from": "human", "value": "Describe this molecule. [13C][=Branch1][C][=O][Branch1][C][N][N]"}, {"from": "gpt", "value": "The molecule is a (13)C-modified compound that is urea in which the carbon is present as its (13)C isotope. It is a (13)C-modified compound and a one-carbon compound."}]