fuchsin

Fuchsine
Identifiers
CAS number	632-99-5 Y
RTECS number	8053-09-6
SMILES	C(\c1cc(c(N)cc1)C)(c1ccc(N)cc1)=C1/C=CC(=N)C=C1.Cl
Properties
Molecular formula	C20H19N3·HCl
Molar mass	337.86 g/mol (hydrochloride)
Melting point	200°C
Solubility in water	2650 mg/L (25°C)
log P	2.920
Vapor pressure	7.49E-10 mm Hg (25°C)
kH	2.28E-15 atm-m3/mole (25°C)
Atmospheric OH rate constant	4.75E-10 cm3/molecule-sec (25°C)
Hazards
Main hazards	Ingestion, inhalation, skin and eye contact, combustible at high temperature, slightly explosive around open flames and sparks.[1]
NFPA 704	1 2 0
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Fuchsine or rosaniline hydrochloride is a magenta dye with chemical formula C₂₀H₁₉N₃·HCl.^[2][3] There are other similar chemical formulations of products sold as fuchsine, and several dozen other synonyms of this molecule.^[2]

It becomes magenta when dissolved in water; as a solid, it forms dark green crystals. As well as dying textiles, fuchsine is used to stain bacteria and sometimes as a disinfectant. In the literature of biological stains the name of this dye is frequently mis-spelled, with omission of the terminal e, which indicates an amine^[4] American and English dictionaries (Webster's, Oxford, Chambers etc) give the correct spelling, which is also used in the literature of industrial dyeing^[5].

History

Fuchsine, named by its original manufacturer Renard frères et Franc,^[6] is usually cited with one of two etymologies: from the color of the flowers of the plant genus Fuchsia,^[7] named in honor of botanist Leonhart Fuchs, or as the German translation Fuchs of the French name Renard, which means fox.^[8] An 1861 article in Répertoire de Pharmacie said that the name was chosen for both reasons.^[9]

Acid fuchsine

Acid fuchsine is a mixture of homologues of basic fuchsin, modified by addition of sulfonic groups. While this yields twelve possible isomers, all of them are satisfactory despite slight differences in their properties.

Basic fuchsine

Basic fuchsine is a mixture of rosaniline, pararosaniline, new fuchsine and Magenta II ^[10]. Formulations usable for making of Schiff reagent must have high content of pararosanilin. The actual composition of basic fuchsine tends to somewhat vary by vendor and batch, making the batches differently suitable for different purposes.

In solution with phenol as an accentuator it is called carbol fuchsin and is used for the staining of the bacterium which causes tuberculosis.^[11]

See also

• New fuchsine and Fuchsine acid are related dyes
• Fuchsine is a component in the Schiff test
• Fuchsine is now often used in the Gram stain procedure in microbiology.

References