
Indigo carmine
Indigo carmine 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 two-colour indicator, a histological dye and a food colouring. It contains an indigo carmine(2-). — ChEBI
- IUPAC name
- disodium;2-(3-hydroxy-5-sulfonato-1H-indol-2-yl)-3-oxoindole-5-sulfonate
- Molecular formula
- C16H8N2Na2O8S2
- Molecular weight
- 466.4 g/mol
- Exact mass
- 465.95174613 Da
- Topological polar surface area
- 197.0 Ų
- Hydrogen-bond donors
- 2
- Hydrogen-bond acceptors
- 9
- Covalent units
- 3
- Defined stereocentres
- 0
Also known as
16 more reported names
External database identifiers
- ChEBI:CHEBI:31695
- ChEMBL:CHEMBL2105023
- EPA DTXSID:DTXSID1020190
Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.