Green S

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Green S
Skeletal formula of Green S
Ball-and-stick model of Green S as a sodium salt
IUPAC name
Sodium 4-[(4-dimethylaminophenyl)-(4-dimethylazaniumylidene-1-cyclohexa-2,5-dienylidene)methyl]-3-hydroxynaphthalene-2,7-disulfonate
Other names
  • Food green S
  • FD&C green 4
  • acid green 50
  • lissamine green B
  • wool green S
  • C.I. 44090
  • E142
3D model (JSmol)
ECHA InfoCard 100.019.463 Edit this at Wikidata
E number E142 (colours)
  • InChI=1S/C27H26N2O7S2.Na/c1-28(2)20-9-5-17(6-10-20)25(18-7-11-21(12-8-18)29(3)4)26-23-14-13-22(37(31,32)33)15-19(23)16-24(27(26)30)38(34,35)36;/h5-16H,1-4H3,(H2,31,32,33,34,35,36);/q;+1/p-1 checkY
  • InChI=1/C27H26N2O7S2.Na/c1-28(2)20-9-5-17(6-10-20)25(18-7-11-21(12-8-18)29(3)4)26-23-14-13-22(37(31,32)33)15-19(23)16-24(27(26)30)38(34,35)36;/h5-16H,1-4H3,(H2,31,32,33,34,35,36);/q;+1/p-1
  • [Na+].[O-]S(=O)(=O)c1ccc4c(c1)cc(c(O)c4/C(=C2\C=C/C(=[N+](/C)C)/C=C2)c3ccc(N(C)C)cc3)S([O-])(=O)=O
Molar mass 576.62 g/mol
Melting point 210 °C (410 °F; 483 K) (decomposes)[1]
GHS labelling:[2]
GHS07: Exclamation mark
H302, H315, H319, H335
P261, P305+P351+P338
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Green S is a green synthetic coal tar triarylmethane dye with the molecular formula C27H25N2O7S2Na.

As a food dye, it has E number E142. It can be used in mint sauce, desserts, gravy granules, sweets, ice creams, and tinned peas. Green S is prohibited as a food additive in Canada, United States, Japan, and Norway.[citation needed] It is approved for use as a food additive in the EU[3] and Australia and New Zealand.[4]

Green S is a vital dye, meaning it can be used to stain living cells. It is used in ophthalmology, along with fluorescein and rose bengal, to diagnose various disorders of the eye's surface, dry eyes for example.


  1. ^ "Safety Data Sheet for Green S". Sigma-Aldrich.
  2. ^ Sigma-Aldrich Co., Green B. Retrieved on 2019-06-09.
  3. ^ UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.
  4. ^ Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". Retrieved 2011-10-27.

External links[edit]