Molekula
Congo Red (CI.22120)
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 2000 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Congo Red (CI.22120) is a synthetic azo dye used in histology for staining connective tissues and in biochemical assays. It is a sodium salt with the molecular formula C32H22N6Na2O6S2 and a molecular weight of 696.66 g/mol. CAS number: 573-58-0. Store at ambient temperature. Hazardous: Signal word Danger. Molekula supplies Congo Red (CI.22120) from research to bulk quantities with full documentation and ISO 9001:2015 traceability.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
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100 g — $82.40 per pack
Need a different quantity or pack?
Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
Prices exclude VAT/sales tax and shipping.
Specifications
| Property | Value |
|---|---|
| Appearance | Red powder |
| Loss on Drying | ≤10% |
| Wavelength of Max. Absorption | 495.0 - 503.0nm |
| Specific Absorbance (E 1%/1cm) | ≤500 |
| Solubility (0.1% water) | Clear red solution |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Acidity | Base |
Identification
| Property | Value |
|---|---|
| SKU | 24120761 |
| CAS Number | 573-58-0 |
| IUPAC Name | disodium;4-amino-3-[[4-[4-[(1-amino-4-sulfonatonaphthalen-2-yl)diazenyl]phenyl]phenyl]diazenyl]naphthalene-1-sulfonate |
| EC Number | 209-358-4 |
| Molecular Formula | C32H22N6Na2O6S2 |
| Molecular Weight | 696.66 |
| Exact Mass | 696.0838 |
| SMILES | C1=CC=C2C(=C1)C(=CC(=C2N)N=NC3=CC=C(C=C3)C4=CC=C(C=C4)N=NC5=C(C6=CC=CC=C6C(=C5)S(=O)(=O)[O-])N)S(=O)(=O)[O-].[Na+].[Na+] |
| InChIKey | IQFVPQOLBLOTPF-UHFFFAOYSA-L |
| InChI | InChI=1S/C32H24N6O6S2.2Na/c33-31-25-7-3-1-5-23(25)29(45(39,40)41)17-27(31)37-35-21-13-9-19(10-14-21)20-11-15-22(16-12-20)36-38-28-18-30(46(42,43)44)24-6-2-4-8-26(24)32(28)34;;/h1-18H,33-34H2,(H,39,40,41)(H,42,43,44);;/q;2*+1/p-2 |
| PubChem CID | 11313 |
| REACH Code | Y110 |
| TSCA Listed | Yes |
| HTS Code | 3212.90.00.50 |
| Tariff Code | 3212900000 |
Safety & GHS
-
Health Hazard
GHS07
-
Serious Health Hazard
GHS08
Hazard statements
- H319 Causes serious eye irritation
- H350 May cause cancer
- H361d Suspected of damaging fertility. Suspected of damaging the unborn child.
Precautionary statements
- P201 Obtain special instructions before use
- P260 Do not breathe dust/fume/gas/mist/vapours/spray
- P263 Avoid contact during pregnancy/while nursing
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P305+351+338 IF IN EYES: Rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing
- P308+313 IF exposed or concerned: Get medical advice/attention
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Portuguese, Spanish.
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Synonyms
- Benzo Congo Red
- C.I. Direct Red 28
- Congazone sodium
- Congo red
- Cotton Red L
- DIRECT RED 28
- Haemomedical
- Haemonorm
- Hemorrhagyl
- Mitsui Congo Red
Frequently asked questions
What is Congo Red used for?
Congo Red is primarily used as a pH indicator and in dyeing textiles and paper. It is also employed in histology for staining connective tissues.
What is the chemical formula and molecular weight of Congo Red?
The formula is C32H22N6Na2O6S2 with a molecular weight of 696.66 g/mol.
How should Congo Red be stored?
Congo Red should be stored at ambient temperature, protected from light and moisture.
What grade of Congo Red does Molekula supply?
Molekula supplies Congo Red in analytical grade, suitable for laboratory and research use.
Can Molekula supply Congo Red in bulk?
Yes, Molekula can supply Congo Red in bulk quantities—please contact our sales team for pricing and availability.
What documentation comes with a Congo Red order?
Each order includes a Certificate of Analysis (CoA) and Safety Data Sheet (SDS) compliant with GHS standards.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.