Oxalic acid dihydrate
Oxalic acid dihydrate (CAS: 6153-56-6) is a dicarboxylic acid with the chemical formula HO₂CCO₂H · 2H₂O. This white crystalline solid, with a molecular weight of 126.07 g/mol, is known for its acidic properties and reducing capabilities. It finds application in various industrial processes, including cleaning, bleaching, and as a reagent in chemical synthesis and analysis. Tech Serve Solutions supplies this compound in a puriss. p.a. grade.
- IUPAC
- Ethanedioic acid
- Synonyms
- Ethanedioic acidOxalic acidOxalic acid, ...dihydrate

Analytical Reagent
Oxalic acid dihydrate serves as a standard for acid-base titrations and as a precipitating agent in analytical chemistry due to its ability to form insoluble oxalates with many metal ions.
Cleaning and Bleaching Agent
Its reducing properties make it effective for removing rust stains from various materials and for bleaching wood and textiles. It is also used in metal surface treatment.
Chemical Synthesis
This compound is employed as a precursor or reagent in the synthesis of various organic and inorganic compounds, contributing to the production of dyes, pharmaceuticals, and other specialty chemicals.
Laboratory Research
In research laboratories, oxalic acid dihydrate is utilized for its properties in experimentation, particularly in fields requiring acidic or reducing agents.
| Molecular weight | 126.07 |
|---|---|
| Linear formula | HO2CCO2H · 2H2O |
| Assay | ≥99.5% (RT) |
| Grade | puriss. p.a. |
| Solubility | H2O: soluble1 M at 20 °C, clear, colorless |
| pH | ~1.0 (25 °C, 1 M in H2O) |
| Vapour pressure | <0.01 mmHg (20 °C) |
| Melting point | 100-102 °C104-106 °C(lit.) |
| Vapour density | 4.4 (vs air) |
| Impurities tested | ≤0.001% total nitrogen (N) |

Hazard statements
- H302Harmful if swallowed
- H312Harmful in contact with skin
Precautionary statements
- P280Wear protective gloves, clothing and eye/face protection
| Protective equipment | dust mask type N95 (US), Eyeshields, Gloves |
|---|---|
| Transport (UN / ADR) | UN 3261 8 / PGIII |
| Water hazard class (WGK, DE) | 1 |
| Hazard codes (EU) | Xn |
| Risk statements (R) | 21/22 |
| Safety statements (S) | 24/25 |
| Cation traces | Ca: ≤10 mg/kgCd: ≤5 mg/kgCo: ≤5 mg/kgCr: ≤5 mg/kgCu: ≤5 mg/kgFe: ≤2 mg/kgK: ≤50 mg/kgMg: ≤5 mg/kgMn: ≤5 mg/kgNa: ≤50 mg/kgNi: ≤5 mg/kgPb: ≤5 mg/kgZn: ≤5 mg/kg |
| Anion traces | chloride (Cl-): ≤5 mg/kgsulfate (SO42-): ≤50 mg/kg |
| Ignition residue | ≤0.01% (as SO4) |
Hazard information is provided for guidance. Always consult the product Safety Data Sheet (SDS), available on request, before handling.
| Absorption | absorption1M/303 nm, H2O cut-off |
|---|---|
| Ign Residue 900 °C | ≤0.01% (as SO4) |
Documentation
Every batch ships with a Certificate of Analysis covering assay, identity and purity; the grade is confirmed against your enquiry. Safety Data Sheets and technical data sheets are available on request.
Supply & logistics
Samples for technical evaluation; bulk MOQ by grade and packaging. In-stock material ships in 7–10 working days, worldwide, with full export documentation.
What is oxalic acid dihydrate used for?
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Oxalic acid dihydrate is used as an analytical reagent, a cleaning and bleaching agent, in chemical synthesis, and for general laboratory research.
What is the CAS number and chemical formula for oxalic acid dihydrate?
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The CAS number for oxalic acid dihydrate is 6153-56-6, and its chemical formula is HO₂CCO₂H · 2H₂O.
What grade and purity does Tech Serve Solutions supply?
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Tech Serve Solutions supplies oxalic acid dihydrate in a puriss. p.a. grade with an assay of ≥99.5% (RT).
What are the primary safety concerns when handling oxalic acid dihydrate?
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Oxalic acid dihydrate is harmful if swallowed (H302) and harmful in contact with skin (H312). Appropriate personal protective equipment, including a dust mask type N95, eyeshields, and gloves, should be used.
How is oxalic acid dihydrate packed, shipped, and exported?
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Oxalic acid dihydrate is classified under UN 3261, Hazard Class 8, Packing Group III, indicating it is shipped as corrosive material. TSS complies with all regulations for safe handling and export.
How can I request a sample or quote for oxalic acid dihydrate?
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To request a sample or quote, please contact our sales team through the website or by calling us directly. Provide the product name and CAS number for efficient processing.
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