Copper(II) acetate

Copper(II) acetate, also referred to as cupric acetate, is the chemical compound with the formula Cu(OAc)2 where AcO− is acetate (CH3CO−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(II) acetate, also referred to as cupric acetate, is the chemical compound with the formula Cu(OAc)2 where AcO− is acetate (CH3CO−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. Copper(II) acetate is prepared industrially by heating copper(II) hydroxide or copper(II) carbonate with acetic acid. Heating a mixture of anhydrous copper(II) acetate and copper metal affords copper(I) acetate: