indigo
Also known as FD&C blue no 2, E132 Indigo Carmine, indigo dye, Indigotine
chemical compound; food additive and dye
Chemical data
- Formula
- C16H10N2NaO8S2+
- Molecular weight
- 445.4 g/mol
- IUPAC name
- sodium 2-(3-hydroxy-5-sulfo-1H-indol-2-yl)-3-oxoindole-5-sulfonic acid
- SMILES
- C1=CC2=C(C=C1S(=O)(=O)O)C(=C(N2)C3=NC4=C(C3=O)C=C(C=C4)S(=O)(=O)O)O.[Na+]
- InChIKey
- GSFNWGKBQZDYCL-UHFFFAOYSA-N
- Polar surface area
- 191 Ų
- H-bond donors
- 4
- H-bond acceptors
- 9
- Formal charge
- 1
via PubChem
Wikidata facts
- Image
- Indian indigo dye lump.jpg
Sources (3)
Article
Indigo dye is an organic compound with a distinctive blue color. Indigo is a natural dye obtained from the leaves of some plants of the Indigofera genus, in particular Indigofera tinctoria. Dye-bearing Indigofera plants were once common throughout the world. Blue colorants are relatively rare. Since indigo is insoluble, it is also referred to as a pigment (C.I. Pigment Blue 66, C.I.).
Most indigo dye produced today is synthetic, constituting around 80,000 tonnes each year, as of 2023. It is most commonly associated with the production of denim cloth and blue jeans, where its properties allow for effects such as stone washing and acid washing to be applied quickly.