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Small crystals of copper(II) acetate
Copper(II) acetate crystals on copper wire
3D model (JSmol)
|Molar mass||181.63 g/mol (anhydrous)|
199.65 g/mol (hydrate)
|Appearance||Dark green crystalline solid|
|Density||1.882 g/cm3 (hydrate)|
|Melting point||Undetermined |
|Boiling point||240 °C (464 °F; 513 K)|
7.2 g/100 mL (cold water)
20 g/100 mL (hot water)
|Solubility||Soluble in alcohol|
Slightly soluble in ether and glycerol
Refractive index (nD)
|Safety data sheet||Baker MSDS|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|710mg/kg oral rat |
|US health exposure limits (NIOSH):|
|TWA 1 mg/m3 (as Cu)|
|TWA 1 mg/m3 (as Cu)|
IDLH (Immediate danger)
|TWA 100 mg/m3 (as Cu)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Copper(II) acetate, also referred to as cupric acetate, is the chemical compound with the formula Cu(OAc)2 where AcO− is acetate (CH
2). The hydrated derivative, which contains one molecule of water for each Cu atom, is available commercially. Anhydrous Cu(OAc)2 is a dark green crystalline solid, whereas Cu2(OAc)4(H2O)2 is more bluish-green. Since ancient times, copper acetates of some form have been used as fungicides and green pigments. Today, copper acetates are used as reagents for the synthesis of various inorganic and organic compounds. Copper acetate, like all copper compounds, emits a blue-green glow in a flame. The mineral hoganite is a naturally occurring form of copper(II) acetate.
Copper acetate hydrate adopts the paddle wheel structure seen also for related Rh(II) and Cr(II) tetraacetates. One oxygen atom on each acetate is bound to one copper at 1.97 Å (197 pm). Completing the coordination sphere are two water ligands, with Cu–O distances of 2.20 Å (220 pm). The two five-coordinate copper atoms are separated by only 2.62 Å (262 pm), which is close to the Cu–Cu separation in metallic copper. The two copper centers interact resulting in a diminishing of the magnetic moment such that near 90 K, Cu2(OAc)4(H2O)2 is essentially diamagnetic due to cancellation of the two opposing spins. Cu2(OAc)4(H2O)2 was a critical step in the development of modern theories for antiferromagnetic coupling.
Unlike the copper(II) derivative, copper(I) acetate is colourless and diamagnetic.
"Basic copper acetate" is prepared by neutralizing an aqueous solution of copper(II) acetate. The basic acetate is poorly soluble. This material is a component of verdigris, the blue-green substance that forms on copper during long exposures to atmosphere.
The reaction proceeds via the intermediacy of copper(I) acetylides, which are then oxidized by the copper(II) acetate, releasing the acetylide radical. A related reaction involving copper acetylides is the synthesis of ynamines, terminal alkynes with amine groups using Cu2(OAc)4. It has been used for hydroamination of acrylonitrile.
It is also an oxidising agent in Barfoed's test.
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Acetyl halides and salts of the acetate ion