[{"from": "human", "value": "What can you tell me about this molecule? [C][=C][C][=C][Branch1][=N][C][=C][Ring1][=Branch1][S][=Branch1][C][=O][=Branch1][C][=O][O-1][C][=Branch2][Ring1][P][=C][Branch1][Ring2][N][Ring1][O][C][=N][C][=C][Branch1][Branch1][C][Ring1][Branch1][=O][C][=C][Branch1][Branch1][C][=C][Ring1][Branch2][S][=Branch1][C][=O][=Branch1][C][=O][O-1][O].[Na+1].[Na+1]"}, {"from": "gpt", "value": "The molecule is an organic sodium salt resulting from the formal condensation of indigo carmine (acid form) with two equivalents of sodium hydroxide. It is an indicator at pH 11.5-14, changing from blue to yellow. It has a role as a food colouring, a histological dye and a two-colour indicator. It contains an indigo carmine(2-)."}]