C 2465
Congo Red 4B, Cosmos Red, Cotton Red B, Cotton Red C, Direct Red 28, Direct Red R, Direct Red Y
573-58-0
for microscopy
C32H22N6Na2O6S2
32041421
696.65
Bottle / Drum
18%
Congo red is the sodium salt of 3,3'-([1,1'-biphenyl]-4,4'-diyl)bis(4-aminonaphthalene-1-sulfonic acid) (formula: C32H22N6Na2O6S2; molecular weight: 696.66 g/mol). It is a secondary diazo dye. Congo red is water-soluble, yielding a red colloidal solution; its solubility is better in organic solvents such as ethanol.
C 2465 (OTTO) Congo red, indicator Cas 573-58-0 - used with litmus paper in a simple parlor trick: add a drop or two of Congo red to both an acid solution and a base solution.
Hematology & histology
Powder
Dye content, ≥85%
>360 °C(lit.)
22120
Hazard Codes TRisk Statements 45-63Safety Statements 53-45WGK Germany 3
845-10-3
7114-03-6
1064-48-8
1934-16-3