Fuchsine

[1][2] There are other similar chemical formulations of products sold as fuchsine, and several dozen other synonyms of this molecule.

In the literature of biological stains the name of this dye is frequently misspelled, with omission of the terminal -e, which indicates an amine.

[7][8] François-Emmanuel Verguin [fr] discovered the substance independently of Hofmann the same year and patented it.

They leave dark greenish streaks on paper and when these are moistened with a solvent, the strong magenta colour appears.

If one of these is protonated to form ABCNH+, the positive charge is delocalized across the whole symmetrical molecule due to pi cloud electron movement.

The positive charge can be thought of as residing on the central carbon atom and all three "wings" becoming identical aromatic rings terminated by a primary amine group.

The ability of fuchsine to be protonated by a stronger acid gives it its basic property.

Solid Basic Fuchsine
Solid Basic Fuchsine
Basic Fuchsine in aqueous solution
Basic Fuchsine in aqueous solution
NFPA 704 four-colored diamond Health 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroform Flammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oil Instability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogen Special hazards (white): no code
Basic fuchsine pieces. The two magenta stains on the paper were made by placing one drop of ethanol -water azeotrope , centre , and water, right , on the streaks remaining on the paper after the 'crystals' were removed. The 'crystals' were then replaced and the photograph taken.