Basic Physical and Chemical Properties of Oxalic acid Dihydrate 99.5% CAS 6153-56-6

Product name: Oxalic Acid Dihydrate

CAS No.: 6153-56-6

Molecular Formula: C2H6O6

Molecular weight: 126.07

Appearance: Colorless, transparent monoclinic crystals / white crystalline particles

Solubility: Soluble in cold and hot water; slightly soluble in ethanol, insoluble in hydrocarbons and fats; aqueous solution exhibits strong acidity

Stability: Stable under sealed storage at room temperature; gradually loses crystalline water and decomposes above 104°C. 

Basic Definition 

Oxalic acid dihydrate, commonly known as ethanedioic acid dihydrate, is the simplest saturated dicarboxylic acid and the most commonly used stable crystalline form in industry. With its strong complexation capability, reducing properties, and mild acidity, it is widely applied across various industries for cleaning, purification, surface treatment, and chemical synthesis. 

Mainstream Industry Applications 

- Metal Processing and Industrial Cleaning (Largest Consumption Sector)

It can form soluble oxalate complexes with rust and iron oxide, widely used for rust removal, scale removal, and polishing of carbon steel, copper parts, aluminum alloys, and hardware components; as well as for removing scale and mineral deposits from equipment and pipelines. Compared to inorganic strong acids, it causes less corrosion to the base metal, making it suitable for cleaning precision parts and maintaining rust removal in ship steel structures.

- Textile, paper, and wood industries

Wood processing: Bleaching and natural color spot removal of wood; additives for waste paper deinking. 

- Rare earth and mineral smelting industry

Core precipitant for rare earth mineral processing and separation purification; oxalate precipitation method for separating various rare earth elements; ore cleaning to remove surface oxidation impurities. 

- Daily chemical, light industry, and stone processing

Stone (marble, limestone) polishing and brightening; raw material for household/commercial rust-removing and cleaning agents; degreasing and softening agent for leather tanning processes. 

- Chemical laboratory & analytical field

Standard reference reagents; Potassium permanganate standard solution calibration material; Metal ion masking agents, gravimetric precipitation reagents. 

- Pharmaceuticals, fine chemical synthesis

As an intermediate, it is used in the synthesis of antibiotics, dyes, and fragrances; as a purification agent for refining pharmaceutical active ingredients. 

- General water treatment scenarios

Heavy metal scavenger for circulating water and process water; complexes calcium, magnesium, and iron ions in water to assist in scale inhibition; typically used in compound formulations, rarely added individually.

Quality specification

Packing and Storage

Packed in 25kg kraft paper bags with PE inner liner.

Store in a cool, dry and well ventilated warehouse. Keep away from sunlight, rain and moisture. Keep sealed to prevent moisture absorption and caking. Separated from strong alkaline materials and oxidizing agents. Do not stack directly on damp ground.