Congo Red, Certified 

Congo red is a benzidine-based anionic diazo histological dye.  It is used as a counterstain.

Specifications:

Synonyms:                                                              Congo Red 4B, Cosmos Red, Cotton Red B, Cotton Red C, Direct Red 28, Direct Red R, Direct Red Y

CAS No:                                                                   573-58-0

Chemical Formula:                                                C32H22N6Na2O6S2

Formula Weight:                                                    696.66

Color Index No.:                                                    22120

Form:                                                                      Powder

Solubility:                                                               H2O: 10 mg/mL