Zinc acetate
Zinc acetate is a salt with the formula Zn(O2CCH3)2, which commonly occurs as 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. When used as a food additive, it has the E number E650.
Basic properties and structures
In anhydrous zinc acetate the zinc is coordinated to four oxygen atoms to give a tetrahedral environment, these tetrahedral polyhedra are then interconnected by acetate ligands to give a range of polymeric structures. 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.
Basic zinc acetate
Heating Zn(CH3CO2)2 in a vacuum results in a 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 beryllium compound, although it is slightly expanded with Zn-O distances ~1.97 vs ~1.63 Å for Be4O(OAc)6.