- Cadmium acetate is an inorganic-organic salt with the formula Cd(CH₃COO)₂ in its anhydrous form, most often encountered as the dihydrate Cd(CH₃COO)₂·2H₂O. The compound consists of a cadmium(II) cation (Cd²⁺) coordinated by two acetate anions (CH₃COO⁻).
- The anhydrous form has a molar mass of 230.50 g/mol, while the dihydrate has a molar mass of 266.53 g/mol.
- It is a colorless to white crystalline solid with a mild vinegar-like odor due to the acetate group.
- Cadmium acetate dihydrate typically crystallizes in the monoclinic crystal system. The cadmium ion is coordinated by oxygen atoms from the acetate groups and water molecules, forming distorted octahedral geometry.
- It is readily soluble in water and ethanol, producing neutral to slightly acidic solutions.
- The dihydrate melts at about 256 °C (with decomposition), and upon heating, it loses its water of crystallization before decomposing to cadmium oxide and organic byproducts. The specific gravity of the dihydrate is around 2.01.
- Cadmium acetate can be prepared by reacting cadmium oxide, cadmium hydroxide, or cadmium carbonate with acetic acid:
- CdO + 2 CH₃COOH → Cd(CH₃COO)₂ + H₂O
- CdCO₃ + 2 CH₃COOH → Cd(CH₃COO)₂ + CO₂↑ + H₂O
- The resulting solution is evaporated to crystallize cadmium acetate, often yielding the dihydrate under normal atmospheric conditions.
- Cadmium acetate is stable under normal storage but should be kept in tightly closed containers to prevent moisture uptake or contamination. In aqueous solutions, it dissociates completely into cadmium(II) ions and acetate ions. Upon heating, it undergoes thermal decomposition, yielding cadmium oxide (CdO), water, acetic acid vapors, and other volatile organic products. In organic synthesis, cadmium acetate can act as a cadmium source in the preparation of other cadmium salts, organocadmium compounds, and cadmium-based catalysts.
- Cadmium acetate is used in the preparation of cadmium-containing pigments (e.g., cadmium sulfide, cadmium sulfoselenide) and as a precursor for cadmium plating solutions. It finds use in the synthesis of quantum dots and semiconductor nanoparticles due to its good solubility in organic solvents when paired with coordinating ligands. In specialized organic synthesis, cadmium acetate has been used in carbon-carbon bond-forming reactions, including some cross-coupling processes as an additive. It has also been applied in the textile industry as a mordant for dyeing and printing fabrics, although this use is now rare due to toxicity concerns.
- Cadmium acetate is highly toxic and carcinogenic. It is harmful if inhaled, ingested, or absorbed through the skin. Acute exposure may cause severe irritation of the respiratory tract, nausea, vomiting, abdominal pain, and diarrhea. Chronic exposure to cadmium compounds is linked to kidney damage, bone demineralization, and increased cancer risk, particularly of the lungs and prostate. Cadmium has a long biological half-life (10–30 years), leading to bioaccumulation in the body over time.
- Cadmium acetate is highly toxic to aquatic life and persistent in the environment. If released into water or soil, it can contaminate ecosystems and bioaccumulate in plants and animals, ultimately entering the food chain. Disposal requires it to be collected as hazardous waste; it must not be discharged into sewers or natural waterways.
- Cadmium acetate is regulated under numerous international chemical safety frameworks, including EU REACH and U.S. EPA hazardous substances lists. It is generally transported under UN 2570 – Cadmium compounds, n.o.s., hazard class 6.1 (toxic substances). Occupational exposure limits for cadmium compounds are typically ≤0.005 mg/m³ (as Cd) for an 8-hour time-weighted average.
