What Is Zinc Acetate?
Zinc acetate is a salt with the formula Zn(CH3CO2)2. Colorless solids, both the hydrate and anhydrous forms are widely used in chemical synthesis and as dietary supplements. Acetic acid reacts with zinc carbonate or zinc metal to produce zinc acetates. It has the E number E650 when used as a food additive.
It can be found in two forms: anhydrous and dihydrate. It's a crystalline white solid. It has astringent properties. It's a zinc molecular object as well as an acetate salt.
The formula of Zinc acetate is Zn(CH3COO)2(H2O)2
The molecular weight of Zinc acetate is 219.50 g/mol (dihydrate)
The density of Zinc acetate is 1.735 g/cm3 (dihydrate)
The melting point of Zinc acetate is 237 °C (Decomposes)
The boiling point of Zinc acetate
The appearance of zinc acetate is White solid (all forms)
Solubility in water is 43 g/100 mL (20 °C, dihydrate)
Solubility in methanol is 1.5 g/100 mL
Magnetic susceptibility (χ) is −101.0·10−6 cm3/mol (H2O)
Zinc Acetate Structure
Zinc is coordinated to four oxygen atoms in anhydrous zinc acetate to form a tetrahedral environment; these tetrahedral polyhedra are then interconnected by acetate ligands to form a variety of polymeric structures.
The zinc in zinc acetate dihydrate is octahedral, with both acetate groups being bidentate.
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Let us look at the Properties of Zinc acetate.
Properties of Zinc Acetate
In a vacuum, heating Zn(CH3CO2)2 allows the acetic anhydride to evaporate, leaving a trace of basic zinc acetate with the formula Zn4O(CH3CO2)6. The tetrahedral structure of this cluster compound is shown above. While it is slightly extended with Zn-O lengths, this species closely resembles the corresponding beryllium compound.
Uses of Zinc Acetate
Lozenges containing zinc acetate have been used to treat the common cold. Treatment for zinc deficiency can also be done with zinc acetate. As part of the cure for Wilson's disease, it is taken as an oral daily supplement to prevent the body from absorbing copper. Zinc acetate is also available as an astringent in the form of an ointment, a topical lotion, or a combination of zinc acetate and an antibiotic such as erythromycin for the treatment of acne on the skin. It's most widely used as an anti-itch ointment.
Wood protection, the manufacture of other zinc salts, polymers, the manufacture of ethyl acetate, as a dye mordant, and analytical reagent are all examples of industrial applications. It's used as a plating inhibitor on primary water piping in commercial nuclear power plants.
Health Hazards
Inhaling zinc diacetate can cause slight irritation of the throat and nose, resulting in sneezing and coughing. Swallowing damages or irritates the gastrointestinal tract, resulting in vomiting. It's a non-flammable substance.
Did You Know?
Acrodermatitis enteropathica is a rare disease in Denmark, with a prevalence of one in every 500000 people. The exact cause of poor zinc absorption is unclear, but a tryptophan derivative called picolinic acid has been suggested as the deficient ligand. Symptoms typically occur 4–6 weeks after weaning, or sometimes earlier in infants who are not consuming breast milk. The child becomes irritable and withdraws, and photophobia grows. Untreated cases may result in anorexia, pica, growth deficiency, hypogonadism, impaired taste and smell, night blindness, and neuropsychiatric symptoms (mood swings, tremors, dysarthria, and jitteriness).
Zinc has been used as a therapeutic modality for decades, whether in its elemental form or its different forms (salts). Zinc oxide, calamine, and zinc pyrithione are topical formulations that have been used as photo protectants, relaxing agents, and active ingredients in anti-dandruff shampoos. It's been used for a range of dermatological conditions over the years, including infections (warts, leishmaniasis), inflammatory dermatoses (acne vulgaris, rosacea), pigmentary disorders (melasma), and neoplasias (skin cancers) (basal cell carcinoma). While the importance of oral zinc in human zinc deficiency syndromes such as acrodermatitis enteropathica has been recognized for some time, the importance of zinc as a micronutrient necessary for infant growth and development has only recently been recognized.
FAQs on Zinc Acetate
1. What is zinc acetate and what is its chemical formula?
Zinc acetate is a salt that is commonly found as a white crystalline solid. It is used in various chemical synthesis processes and as a dietary supplement. The chemical formula for its most common form, the dihydrate, is Zn(CH₃COO)₂(H₂O)₂. The anhydrous (water-free) form has the formula Zn(CH₃CO₂)₂.
2. How can zinc acetate be prepared?
A common method for preparing zinc acetate involves an acid-base reaction. It is typically synthesised by reacting acetic acid with either zinc carbonate or zinc metal. The reaction with zinc carbonate produces zinc acetate, water, and carbon dioxide, while the reaction with zinc metal yields zinc acetate and hydrogen gas.
3. What are the key physical properties of zinc acetate dihydrate?
The key physical properties of zinc acetate dihydrate, as per the CBSE curriculum for 2025-26, include:
- Appearance: White crystalline solid.
- Molecular Weight: Approximately 219.50 g/mol.
- Melting Point: It decomposes at around 237 °C.
- Solubility: It is highly soluble in water (43 g/100 mL at 20 °C) and moderately soluble in methanol.
4. What are the most important uses of zinc acetate in medicine and industry?
Zinc acetate has several important applications:
- In Medicine: It is used as a dietary supplement to treat zinc deficiency, in lozenges to help manage common cold symptoms, and in ointments to treat acne and itching. It also plays a role in managing Wilson's disease by preventing copper absorption.
- In Industry: It is used for wood preservation, as a mordant in dyeing fabrics, in the manufacturing of other zinc salts and polymers, and as a catalyst for producing ethyl acetate.
5. How does the molecular structure of anhydrous zinc acetate differ from zinc acetate dihydrate?
The key difference lies in the coordination geometry around the zinc ion. In anhydrous zinc acetate, the zinc atom is coordinated to four oxygen atoms, resulting in a tetrahedral environment that forms polymeric structures. In contrast, the zinc atom in zinc acetate dihydrate is octahedral, where both acetate groups act as bidentate ligands, and water molecules complete the coordination.
6. Why is zinc acetate considered effective in treating certain skin conditions like acne?
Zinc acetate is effective for skin conditions like acne due to its astringent and anti-inflammatory properties. As an astringent, it helps to cleanse the skin, tighten pores, and dry out excess oil. Its anti-inflammatory action can reduce the redness and swelling associated with acne. It is often combined with antibiotics like erythromycin in topical treatments to also target bacterial growth.
7. What happens when zinc acetate is heated, and what is “basic zinc acetate”?
When zinc acetate is heated strongly in a vacuum, it undergoes decomposition. It doesn't simply melt but loses acetic anhydride to form a residue of basic zinc acetate. This is a cluster compound with the formula Zn₄O(CH₃CO₂)₆. Its structure is a notable example of a metal-oxo cluster, featuring a central oxygen atom tetrahedrally bonded to four zinc atoms.
8. Are there any safety concerns when handling zinc acetate?
Yes, while it is a non-flammable substance, certain precautions are necessary. Inhaling zinc acetate dust can irritate the nose and throat, leading to coughing and sneezing. If swallowed, it can irritate the gastrointestinal tract and cause vomiting. Therefore, when handling it in a laboratory, it is important to use proper ventilation and personal protective equipment (PPE) like gloves and safety glasses.
