Zinc acetate

Zinc acetate is the chemical compound with the formula Zn(O₂CCH₃)₂ but more commonly refers to the dihydrate Zn(O₂CCH₃)₂(H₂O)₂. Both the hydrate and the anhydrous forms are colorless solids that are commonly used in chemical synthesis and as dietary supplements. Zinc acetates are prepared by the action of acetic acid on zinc carbonate or zinc metal.

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Basic properties and structures

Like virtually all zinc compounds, this salt consists of Zn²⁺ ions. The acetate group is capable of binding to metal ions in a variety of ways through its two oxygen atoms and several connectiviites are observed for the various hydrates of zinc acetate. Anhydrous zinc acetate adopts a polymeric structure consisting of zinc coordinated to four oxygen atoms in a tetrahedral environment, each tetrahedron being connected to neighbors by the acetate groups.^[1] The acetate ligands are not bidentate. In contrast, most metal diacetates feature metals in octahedral coordination with bidentate acetate groups. In zinc acetate dihydrate the zinc is octahedral, wherein both acetate groups are bidentate.^[2]

Basic zinc acetate

Heating Zn(CH₃CO₂)₂ in a vacuum results in loss of acetic anhydride, leaving a residue of "basic zinc acetate," with the formula Zn₄O(CH₃CO₂)₆. This cluster compound has the tetrahedral structure shown below. This species closely resembles the corresponding the analogous beryllium compound, although it is slightly expanded with Zn-O distances ~1.97 vs ~1.63 Å for Be₄O(OAc)₆.^[3]

Applications

Dietary and medicinal applications

Zinc acetate is used as a dietary supplement and in lozenges used to treat the common cold. Zinc acetate alone is thought to be more effective at treating the common cold than zinc gluconate.^[4]

Zinc acetate can also used to treat zinc deficiencies. As an oral daily supplement it is used to inhibit the body's absorption of copper as part of the treatment for Wilson's disease. Zinc acetate is also sold as an astringent in the form of an ointment, a topical lotion; or combined with an antibiotic (erythromycin) for the topical treatment of acne.

Industrial applications

Industrial applications include wood preserving, manufacturing other zinc salts, polymers, manufacture of ethylene acetate, as a dye mordant, and analytical reagent.

Zinc acetate is a precursor via a sol-gel route to the transparent semiconductor zinc oxide.

References

1. ^ Capilla, A. V.; Aranda, R. A. “Anhydrous Zinc(II) Acetate (CH₃-COO)₂Zn” Crystal Structure Communications 1979 ,volume 8, 795-797.
2. ^ Van Niekerk, J. N.; Schoening, F. R. L.; Talbot, J. H. “The Crystal Structure of Zinc Acetate Dihydrate, Zn(CH₃COO)₂.H₂O” Acta Crystallographica 1953, volume 6, pages 720-723.
3. ^ Koyama, H.; Saito, Y. “The Crystal Structure of Zinc Oxyacetate, Zn₄O(CH₃COO)₆” Bulletin of the Chemical Society of Japan, 1954, volume 27, pages 112-114.
4. ^ Eby GA (2004). "Zinc lozenges: cold cure or candy? Solution chemistry determinations". Biosci. Rep. 24 (1): 23–39. PMID 15499830.