Congo Red

Also known as: C.I. Direct Red 28, Direct Red 28, Congo Red 4B, Cotton Red B, Cotton Red C, Direct Red R, Direct Red Y, Cosmos Red, Benzo Congo Red, Haemonorm, Congazone sodium, Congo Ared 4b, Congo Red K, Hemorrhagyl, Solucongo, 3,3'-[(1,1'-Biphenyl)-4,4'-diylbis(azo)]bis(4-amino-1-naphthalenesulfonic acid) disodium salt, 3,3'-[[1,1'-Biphenyl]-4,4'-diylbis(azo)]bis[4-amino-1-naphthalenesulfonic acid sodium] salt, disodium 4-amino-3-[[4-[4-[(1-amino-4-sulfonatonaphthalen-2-yl)diazenyl]phenyl]phenyl]diazenyl]naphthalene-1-sulfonate, benzidinediazo-bis-1-naphtylamine-4 sulfonic acid disodium, sodium salt of benzidinediazobis-1-naphthylamine-4-sulfonic acid

Congo Red (CAS 573-58-0) is a compound in the Organic Compounds category listed in the Jingsj chemical database. It has the molecular formula C32H22N6Na2O6S2 and a molecular weight of 696.663 g/mol. Key properties include a melting point of >360 °C(lit.) and a density of 0.995 g/mL at 25 °C. It is classified under GHS with signal word Danger and hazard statements H350 — May cause cancer. It is listed by 1 supplier; request a quote for pricing. Record last updated Nov 3, 2026.

CAS No.

573-58-0

Jingsj CID

J-1098057-0

Molecular Formula

C₃₂H₂₂N₆Na₂O₆S₂

Molecular Weight

696.663 g/mol

Category

Organic Compounds

Last updated

11/3/2026