Molekula
Calconcarboxylic acid
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 1999 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Calconcarboxylic acid is a chromogenic reagent used in analytical chemistry for complexometric titrations, particularly in the detection of metal ions. It functions as an indicator due to its color change upon metal ion binding. Available with CAS number 3737-95-9, molecular formula C21H14N2O7S, and molecular weight 438.41 g/mol. Stored at ambient temperatures. Signal word: Warning.
Molekula supplies Calconcarboxylic acid in 25 g packs, from £50.40 inc. VAT. It is in stock for same-day dispatch. Every batch ships with a certificate of analysis, and safety data sheets are available in 5 languages. Larger quantities, up to multi-tonne, are quoted on request.
Example image for illustration only. Other packaging and pack sizes are available.
Often bought together
Pricing & pack sizes
In stock — same-day dispatch
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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25 g — £42.00 per pack ex VAT · £50.40 inc. VAT
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 | Black/dark violet powder |
| Identification | Conforms to reference |
| Residue on Ignition | ≤0.3% |
| Dissolution Test | Conforms |
| Complexing ability | Conforms |
| Titration Test | Conforms |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Acidity | Acid |
Identification
| Property | Value |
|---|---|
| SKU | 26273667 |
| CAS Number | 3737-95-9 |
| IUPAC Name | 3-hydroxy-4-[(2-hydroxy-4-sulfonaphthalen-1-yl)diazenyl]naphthalene-2-carboxylic acid |
| EC Number | 223-117-0 |
| Molecular Formula | C21H14N2O7S |
| Molecular Weight | 438.41 |
| Exact Mass | 438.0522 |
| SMILES | C1=CC=C2C(=C1)C=C(C(=C2N=NC3=C(C=C(C4=CC=CC=C43)S(=O)(=O)O)O)O)C(=O)O |
| InChIKey | MVQBFZXBLLMXGS-UHFFFAOYSA-N |
| InChI | InChI=1S/C21H14N2O7S/c24-16-10-17(31(28,29)30)13-7-3-4-8-14(13)18(16)22-23-19-12-6-2-1-5-11(12)9-15(20(19)25)21(26)27/h1-10,24-25H,(H,26,27)(H,28,29,30) |
| PubChem CID | 77330 |
| REACH Code | Y113 |
| TSCA Listed | Yes |
| HTS Code | 29270050 |
| Tariff Code | 2927000090 |
Safety & GHS
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Health Hazard
GHS07
Hazard statements
- H315 Causes skin irritation
- H319 Causes serious eye irritation
- H335 May cause respiratory irritation
Precautionary statements
- P261 Avoid breathing dust/fume/gas/mist/vapours/spray
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P302+352 IF ON SKIN: Wash with soap and water
- P305+351+338 IF IN EYES: Rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing
- P333+313 IF skin irritation or a rash occurs: Get medical advice/attention
- P337+313 If eye irritation persists get medical advice/attention
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, 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.
Quality certificates
Molekula Group is certified to ISO 9001:2015 (quality) and ISO 14001:2015 (environmental management), audited by a UKAS-accredited body. Both certificates are valid to 17 May 2028.
Synonyms
- 2-Hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoic acid
- 2-Hydroxy-1-(2-hydroxy-4-sulfo-1-napthylazo)-3-naphthoic acid
- 2,2'-Dihydroxy-4'-sulpho-1,1'-azonaphthalene-3-carboxylic acid
- 3-Hydroxy-4-((2-hydroxy-4-sulfonaphthalen-1-yl)diazenyl)-2-naphthoic acid
- Cal Red
- Calcon 3-carboxylic acid
- Calconcarbonic acid
- Kalces
- Patton and Reeder's indicator
- Patton-Reeder indicator
Frequently asked questions
What is calconcarboxylic acid used for?
Calconcarboxylic acid, also known as the Patton–Reeder indicator, is primarily used as a metal ion indicator in complexometric titrations. It determines calcium in the presence of magnesium. At the high pH used (12–14), magnesium precipitates as the hydroxide and does not respond, so the indicator is selective for calcium.
What is the chemical formula and molecular weight of calconcarboxylic acid?
The chemical formula is C21H14N2O7S and the molecular weight is 438.41 g/mol.
How should calconcarboxylic acid be stored?
It should be stored at ambient temperature, protected from moisture and light.
What grade is available for calconcarboxylic acid?
Molekula supplies calconcarboxylic acid to a specification covering appearance (black/dark violet powder), identification, residue on ignition (≤0.3%), dissolution, complexing ability and titration tests. Please contact our sales team for further details.
Can Molekula supply calconcarboxylic acid in bulk?
Yes, Molekula can supply calconcarboxylic acid in bulk quantities—please contact our sales team for details.
What documentation comes with a purchase of calconcarboxylic acid?
Each order includes a Certificate of Analysis (CoA) and Safety Data Sheet (SDS) with the shipment.
Where can I buy Calconcarboxylic acid?
Directly from Molekula, which lists Calconcarboxylic acid in 25 g packs from £50.40 inc. VAT, with a certificate of analysis for every batch. Larger quantities are quoted on request. Molekula's offices: United Kingdom, France, Spain, Germany, Italy, United States and China.
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.