Acid fuchsin or fuchsine acid, (also called Acid Violet 19^[1] and C.I. 42685^[1]) is an acidic magenta dye with the chemical formula C₂₀H₁₇N₃Na₂O₉S₃. It is a sodium sulfonate derivative of fuchsine. Acid fuchsin has wide use in histology,^[1] and is one of the dyes used in Masson's trichrome stain.^[2] This method is commonly used to stain cytoplasm and nuclei of tissue sections in the histology laboratory in order to distinguish muscle from collagen. The muscle stains red with the acid fuchsin, and the collagen is stained green or blue with Light Green SF yellowish or methyl blue. It can also be used to identify growing bacteria.^[3]

Quick Facts Names, Identifiers ...

Acid fuchsin

Names
IUPAC name Disodium 2-amino-5-[(Z)-(4-amino-3-sulfonatophenyl)(4-iminio-3-sulfonato-2,5-cyclohexadien-1-ylidene)methyl]-3-methylbenzenesulfonate
Identifiers
CAS Number	3244-88-0 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:87052 Y
ChemSpider	16736101 Y
ECHA InfoCard	100.019.833
EC Number	221-816-5
PubChem CID	5464362
UNII	8RA6L21QTM Y
CompTox Dashboard (EPA)	DTXSID8044418
InChI InChI=1S/C20H19N3O9S3.2Na/c1-10-6-13(9-18(20(10)23)35(30,31)32)19(11-2-4-14(21)16(7-11)33(24,25)26)12-3-5-15(22)17(8-12)34(27,28)29;;/h2-9,21H,22-23H2,1H3,(H,24,25,26)(H,27,28,29)(H,30,31,32);;/q;2*+1/p-2/b19-11-,21-14?;; Y Key: RZUBARUFLYGOGC-MTHOTQAESA-L Y InChI=1/C20H19N3O9S3.2Na/c1-10-6-13(9-18(20(10)23)35(30,31)32)19(11-2-4-14(21)16(7-11)33(24,25)26)12-3-5-15(22)17(8-12)34(27,28)29;;/h2-9,21H,22-23H2,1H3,(H,24,25,26)(H,27,28,29)(H,30,31,32);;/q;2*+1/p-2/b19-11-,21-14?;; Key: RZUBARUFLYGOGC-LOQRZINWBG
SMILES CC1=CC(=CC(=C1N)S(=O)(=O)[O-])/C(=C\2/C=CC(=[NH2+])C(=C2)S(=O)(=O)[O-])/C3=CC(=C(C=C3)N)S(=O)(=O)[O-].[Na+].[Na+]
Properties
Chemical formula	C20H17N3Na2O9S3
Molar mass	585.53 g·mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

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• New fuchsine
• Pararosanilin
• Verhoeff’s Stain
• Pollen grain staining (Alexander's stain)