Copper(II) acetate

Small crystals of copper(II) acetate

Copper(II) acetate hydrate

Copper(II) acetate monohydrate

Names
IUPAC name

Tetra-μ2-acetatodiaquadicopper(II)

Other names

Copper(II) ethanoate
Cupric acetate
Copper acetate
Verdigris

Identifiers

CAS Number

* 142-71-2 (anhydrous) Y
* 6046-93-1 (hydrate) Y

3D model (JSmol)

* Interactive image

ChemSpider |

* 8555 Y

ECHA InfoCard | 100.005.049
EC Number |

* 205-553-3

PubChem CID

* 8895

UNII |

* 39M11XPH03 (anhydrous) Y
* 39J9V52S86 (hydrate) Y

UN number | 3077

CompTox Dashboard (EPA)

* DTXSID2059720

InChI

* InChI=1S/2C2H4O2.Cu/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 Y

Key: OPQARKPSCNTWTJ-UHFFFAOYSA-L Y

* InChI=1/2C2H4O2.Cu/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2

Key: OPQARKPSCNTWTJ-NUQVWONBAO

SMILES

* [O+]1C(C)O[Cu-3]23([OH2+])[O+]C(C)O[Cu-3]1([OH2+])(OC(C)[O+]2)OC(C)[O+]3

Properties

Chemical formula

| Cu(CH3COO)2
Molar mass | 181.63 g/mol (anhydrous)
199.65 g/mol (hydrate)
Appearance  | Dark green crystalline solid
Odor | Odorless (hydrate)
Density | 1.882 g/cm3 (hydrate)
Melting point | 115 °C (anhydrous) [1]

Undetermined (hydrate)[2]

Boiling point | 240 °C (464 °F; 513 K)

Solubility in water

| Hydrate:
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)

| 1.545 (hydrate)
Structure

Crystal structure

| Monoclinic
Hazards
GHS labelling:

Pictograms

Signal word

| Danger

Hazard statements

| H301, H302, H311, H314, H410, H411, H412

Precautionary statements

| P260, P264, P270, P273, P280, P301+P310, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P361, P363, P391, P405, P501
NFPA 704 (fire diamond)  |

Flash point | Non-flammable
Lethal dose or concentration (LD, LC):

LD50 (median dose)

| 710 mg/kg oral rat[4]
NIOSH (US health exposure limits):

PEL (Permissible)

| TWA 1 mg/m3 (as Cu)[3]

REL (Recommended)

| TWA 1 mg/m3 (as Cu)[3]

IDLH (Immediate danger)

| TWA 100 mg/m3 (as Cu)[3]
Safety data sheet (SDS)  | Baker MSDS

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

N verify (what is YN ?)

Infobox references

Chemical compound

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, Cu2(OAc)4(H2O)2, which contains one molecule of water for each copper atom, is available commercially. Anhydrous copper(II) acetate 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.[5] Copper acetate, like all copper compounds, emits a blue-green glow in a flame.

## Structure

[edit]

* Copper(II) acetate monohydrate

Copper acetate hydrate adopts the paddle wheel structure seen also for related Rh(II) and Cr(II) tetraacetates.[6][7] One oxygen atom on each acetate is bound to one copper atom at 1.97 Å (0.197 nm). Completing the coordination sphere are two water ligands, with Cu-O distances of 2.20 Å (0.220 nm). The two copper atoms are separated by only 2.62 Å (0.262 nm), which is close to the Cu-Cu separation in metallic copper.[8][9][10][11] The two copper centers interact resulting in a diminishing of the magnetic moment such that at temperatures below 90 K (−297.7 °F), Cu2(OAc)4(H2O)2 is essentially diamagnetic. Cu2(OAc)4(H2O)2 was a critical step in the development of modern theories for antiferromagnetic exchange coupling, which ascribe its low-temperature diamagnetic behavior to cancellation of the two opposing spins on the adjacent copper atoms.[12]

## Synthesis

[edit]

Copper(II) acetate is prepared industrially by heating copper(II) hydroxide or basic copper(II) carbonate with acetic acid.[5]

## Uses in chemical synthesis

[edit]

Copper(II) acetate has found some use as an oxidizing agent in organic syntheses. In the Eglinton reaction Cu2(OAc)4 is used to couple terminal alkynes to give a 1,3-diyne:[13][14]

Cu2(OAc)4 \+ 2 RC≡CH → 2 CuOAc + RC≡C−C≡CR + 2 HOAc

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.[15] It has been used for hydroamination of acrylonitrile.[16]

In chemical analysis, it serves as an oxidizing agent in both the Barfoed's test for presence of monosaccharides and as a precursor to a copper-fatty acid complex in the colorimetric copper soap assay to test for free fatty acids.[17]

It reacts with arsenic trioxide to form copper acetoarsenite, a powerful insecticide and fungicide called Paris green.

### Related compounds

[edit]

Heating a mixture of anhydrous copper(II) acetate and copper metal affords copper(I) acetate:[18][19]

Cu + Cu(OAc)2 → 2 CuOAc

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.[citation needed]

## Other uses

[edit]

A mixture of copper acetate and ammonium chloride is used to chemically color copper with a bronze patina.[20]

## Mineralogy

[edit]

The mineral hoganite is a naturally occurring form of copper(II) acetate.[21][22] A related mineral, also containing calcium, is paceite.[22] Both are very rare.[23][24]

* Copper(II) acetate, crystalline

* Copper(II) acetate, milled

## References

[edit]

1. ^ "Copper(II) acetate | C4H6CuO4 | ChemSpider".
2. ^ Trimble, R. F. (1976). "Copper(II) acetate monohydrate - An erroneous melting point". Journal of Chemical Education. 53 (6): 397. Bibcode:1976JChEd..53..397T. doi:10.1021/ed053p397.
3. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0150". National Institute for Occupational Safety and Health (NIOSH).
4. ^ "Mineral Safety Data Sheet: Copper (II) Acetate, Monohydrate" (PDF). Archived from the original (PDF) on 2011-09-28. Retrieved 2011-06-14.
5. ^ a b Richardson, H. Wayne. "Copper Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a07_567. ISBN 978-3-527-30673-2.
6. ^ Van Niekerk, J. N.; Schoening, F. R. L. (1953). "X-Ray Evidence for Metal-to-Metal Bonds in Cupric and Chromous Acetate". Nature. 171 (4340): 36–37\. Bibcode:1953Natur.171...36V. doi:10.1038/171036a0. S2CID 4292992.
7. ^ Wells, A. F. (1984). Structural Inorganic Chemistry. Oxford: Clarendon Press. ISBN 978-0-19-855370-0.
8. ^ Catterick, J.; Thornton, P. (1977). "Structures and physical properties of polynuclear carboxylates". Adv. Inorg. Chem. Radiochem. Advances in Inorganic Chemistry and Radiochemistry. 20: 291–362\. doi:10.1016/s0065-2792(08)60041-2. ISBN 9780120236206.
9. ^ van Niekerk, J. N.; Schoening, F. R. L. (1953-03-10). "A new type of copper complex as found in the crystal structure of cupric acetate, Cu2(CH3COO)4.2H2O". Acta Crystallographica. 6 (3): 227–232\. Bibcode:1953AcCry...6..227V. doi:10.1107/S0365110X53000715. ISSN 0365-110X.
10. ^ Meester, Patrice de; Fletcher, Steven R.; Skapski, Andrzej C. (1973-01-01). "Refined crystal structure of tetra-µ-acetato-bisaquodicopper(II)". Journal of the Chemical Society, Dalton Transactions (23): 2575–2578\. doi:10.1039/DT9730002575. ISSN 1364-5447.
11. ^ Brown, G. M.; Chidambaram, R. (1973-11-15). "Dinuclear copper(II) acetate monohydrate: a redetermination of the structure by neutron-diffraction analysis". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 29 (11): 2393–2403\. Bibcode:1973AcCrB..29.2393B. doi:10.1107/S0567740873006758. ISSN 0567-7408.
12. ^ Carlin, R. L. (1986). Magnetochemistry. Berlin: Springer. pp. 77–82\. ISBN 978-3642707353.
13. ^ Stöckel, K.; Sondheimer, F. "[18]Annulene". Organic Syntheses. 54: 1. doi:10.15227/orgsyn.054.0001; Collected Volumes, vol. 6, p. 68.
14. ^ Campbell, I. D.; Eglinton, G. "Diphenyldiacetylene". Organic Syntheses. 45: 39. doi:10.15227/orgsyn.045.0039; Collected Volumes, vol. 5, p. 517.
15. ^ Vogel, P.; Srogl, J. (2005). "Copper(II) Acetate". EROS Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons. doi:10.1002/047084289X.rc194.pub2. ISBN 978-0-470-84289-8..
16. ^ Heininger, S. A. "3-(o-Chloroanilino)propionitrile". Organic Syntheses. 38: 14. doi:10.15227/orgsyn.038.0014; Collected Volumes, vol. 4, p. 146.
17. ^ Mustafa, Ahmad; Karmali, Amin; Abdelmoez, Wael (2016). "A Sensitive Microplate Assay for Lipase Activity Measurement Using Olive Oil Emulsion Substrate: Modification of the Copper Soap Colorimetric Method". Journal of Oleo Science. 65 (9): 775–784\. doi:10.5650/jos.ess16066. ISSN 1347-3352. PMID 27581492.
18. ^ Kirchner, S. J.; Fernando, Q.; Darby, Dana; Dilts, J. A. (2007). "Copper(I) Acetate". In Busch, Daryle H. (ed.). Inorganic Syntheses. Vol. 20 (1 ed.). Wiley. pp. 53–55\. doi:10.1002/9780470132517.ch16. ISBN 9780470132517.
19. ^ Parish, E. J.; Kizito, S. A. (2001). "Copper(I) Acetate". Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons. doi:10.1002/047084289X.rc193. ISBN 0471936235.
20. ^ Budija, Goran. "Collection of formulas for the chemical,electrochemical and heat colouring of metals,the cyanide free immersion plating and electroplating" (PDF). Finishing.com. Retrieved December 30, 2023.
21. ^ Musumeci, Anthony; Frost, Ray L. (2007-05-01). "A spectroscopic and thermoanalytical study of the mineral hoganite". Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 67 (1): 48–57\. Bibcode:2007AcSpA..67...48M. doi:10.1016/j.saa.2006.05.037. ISSN 1386-1425. PMID 17321784.
22. ^ a b Hibbs, D. E.; Kolitsch, U.; Leverett, P.; Sharpe, J. L.; Williams, P. A. (June 2002). "Hoganite and paceite, two new acetate minerals from the Potosi mine, Broken Hill, Australia". Mineralogical Magazine. 66 (3): 459–464\. Bibcode:2002MinM...66..459H. doi:10.1180/0026461026630042. ISSN 0026-461X. S2CID 97116531.
23. ^ "Paceite".
24. ^ "List of Minerals". 21 March 2011.

## External links

[edit]

Wikimedia Commons has media related to Copper(II) acetate.

* Copper.org – Other Copper Compounds Archived 2013-08-15 at the Wayback Machine 5 Feb. 2006
* Infoplease.com – Paris green 6 Feb. 2006
* Verdigris – History and Synthesis 6 Feb. 2006
* Australian - National Pollutant Inventory 8 Aug. 2016
* USA NIH National Center for Biotechnology Information 8 Aug. 2016

* v
* t
* e

Copper compounds

Cu(0,I)|

* Cu5Si

Cu(I)|

* CuBr
* CuCN
* CuCl
* CuF
* CuH
* CuI
* Cu2C2
* Cu2Cr2O5
* Cu2O
* CuOH
* CuNO3
* Cu3P
* Cu2S
* CuSCN
* C6H5Cu

Cu(I,II)|

* Cu4O3
* Cu3H4O8S2

Cu(II)|

* Cu(BF4)2
* CuBr2
* CuC2
* Cu(CH3COO)2
* Cu(CF3COO)2
* Cu(C3H5O3)2
* CuCO3
* Cu2CO3(OH)2
* Cu(CN)2
* CuCl2 / KCuCl3 / K2CuCl4
* Cu(ClO3)2
* Cu(ClO4)2
* CuF2
* Cu(NO3)2
* Cu3(PO4)2
* Cu3(BO3)2
* Cu(N3)2
* CuC2O4
* CuO
* CuO2
* Cu(OH)2
* CuS
* Cu(SCN)2
* CuSO4
* Cu3(AsO4)2
* Cu(C
11H
23COO)

* Cu(C17H35COO)2
* Cu(O2CC6H5)2
* CuTe
* CuTe2

Cu(III)|

* K3CuF6
* CuO−

Cu(IV)|

* CuO2
* Cs2CuF6

* v
* t
* e

Acetyl halides and salts of the acetate ion

| AcOH |  |  |  | He

|
|
|
|

LiOAc | Be(OAc)2
Be4O(OAc)6 | B(OAc)3
B2O(OAc)4 | AcOAc
ROAc | NH4OAc | AcOOH | FAc
FOAc | Ne
NaOAc
NaH(OAc)2 | Mg(OAc)2 | Al(OAc)3
ALSOL
Al(OAc)2OH
Al(OH)2OAc
Al2SO4(OAc)4 | Si  | P  | S  | ClAc
ClOAc | Ar
KOAc | Ca(OAc)2 |  | Sc(OAc)3 | Ti(OAc)4 | VO(OAc)2 | Cr(OAc)2
Cr(OAc)3 | Mn(OAc)2
Mn(OAc)3 | Fe(OAc)2
Fe(OAc)3 | Co(OAc)2 | Ni(OAc)2 | CuOAc
Cu(OAc)2 | Zn(OAc)2 | Ga(OAc)3 | Ge  | As(OAc)3 | Se  | BrAc
BrOAc | Kr
RbOAc | Sr(OAc)2 |  | Y(OAc)3 | Zr(OAc)4 | Nb  | Mo(OAc)2 | Tc  | Ru2(OAc)4Cl
Ru(OAc)3 | Rh2(OAc)4 | Pd(OAc)2 | AgOAc | Cd(OAc)2 | In(OAc)3 | Sn(OAc)2
Sn(OAc)4 | Sb(OAc)3 | Te  | IAc
IOAc
I(OAc)3 | Xe
CsOAc | Ba(OAc)2 | *  | Lu(OAc)3 | Hf  | Ta  | W  | Re  | Os  | Ir  | Pt(OAc)2 | Au(OAc)3 | Hg2(OAc)2
Hg(OAc)2 | TlOAc
Tl(OAc)3 | Pb(OAc)2
Pb(OAc)4 | Bi(OAc)3 | Po  | At  | Rn
Fr  | Ra  | **  | Lr  | Rf  | Db  | Sg  | Bh  | Hs  | Mt  | Ds  | Rg  | Cn  | Nh  | Fl  | Mc  | Lv  | Ts  | Og

*  | La(OAc)3 | Ce(OAc)3 | Pr(OAc)3 | Nd(OAc)3 | Pm  | Sm(OAc)3 | Eu(OAc)3 | Gd(OAc)3 | Tb(OAc)3 | Dy(OAc)3 | Ho(OAc)3 | Er(OAc)3 | Tm(OAc)3 | Yb(OAc)3
**  | Ac(OAc)3 | Th(OAc)4 | Pa  | UO2(OAc)2 | NpO2(OAc)2 | PuO2(OAc)2 | Am  | Cm  | Bk  | Cf  | Es  | Fm  | Md  | No
*[CID]: Compound ID
*[EPA]: U.S. Environmental Protection Agency
*[H301]: H301: Toxic if swallowed
*[H302]: H302: Harmful if swallowed
*[H311]: H311: Toxic in contact with skin
*[H314]: H314: Causes severe skin burns and eye damage
*[H410]: H410: Very toxic to aquatic life with long lasting effects
*[H411]: H411: Toxic to aquatic life with long lasting effects
*[H412]: H412: Harmful to aquatic life with long lasting effects
*[P260]: P260: Do not breathe dust/fume/gas/mist/vapours/spray.
*[P264]: P264: Wash ... thoroughly after handling.
*[P270]: P270: Do not eat, drink or smoke when using this product.
*[P273]: P273: Avoid release to the environment.
*[P280]: P280: Wear protective gloves/protective clothing/eye protection/face protection.
*[P301+P310]: P301+P310: IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician.
*[P301+P312]: P301+P312: IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell.
*[P301+P330+P331]: P301+P330+P331: IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
*[P302+P352]: P302+P352: IF ON SKIN: Wash with soap and water.
*[P303+P361+P353]: P303+P361+P353: IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water [or shower].
*[P304+P340]: P304+P340: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing.
*[P305+P351+P338]: P305+P351+P338: IF IN EYES: Rinse continuously with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing.
*[P310]: P310: Immediately call a POISON CENTER or doctor/physician.
*[P312]: P312: Call a POISON CENTER or doctor/physician if you feel unwell.
*[P321]: P321: Specific treatment (see ... on this label).
*[P322]: P322: Specific measures (see ... on this label).
*[P330]: P330: Rinse mouth.
*[P361]: P361: Remove/Take off immediately all contaminated clothing.
*[P363]: P363: Wash contaminated clothing before reuse.
*[P391]: P391: Collect spillage.
*[P405]: P405: Store locked up.
*[P501]: P501: Dispose of contents/container to ...
*[v]: View this template
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