Copper(II) oxalate

Copper(II) oxalate
Names
	Other names Copper (II) oxalate, cupric oxalate, copper(2+) ethanedioate
Identifiers
CAS Number	814-91-5 ; hemihydrate: 55671-32-4;
3D model (JSmol)	Interactive image;
ChemSpider	12596;
ECHA InfoCard	100.011.283
EC Number	212-411-4;
PubChem CID	54602330;
UNII	BN136S94FS ;
UN number	3077
CompTox Dashboard (EPA)	DTXSID0041802 ;
	InChI Key: QYCVHILLJSYYBD-UHFFFAOYSA-N; InChI=1S/C2H2O4.Cu/c3-1(4)2(5)6;/h(H,3,4)(H,5,6);/q;+2;
	SMILES O=C([O-])C([O-])=O.[Cu+2];
Properties
Chemical formula	CuC; 2O; 4
Molar mass	151.56
Appearance	blue solid
Density	6.57 g/cm3
Solubility in water	insoluble
Solubility product (Ksp)	4.43×10−10
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H302+H312, H312
Precautionary statements	P264, P270, P280, P301+P312, P302+P352, P312, P322, P330, P363, P501
Related compounds
Related compounds	Calcium oxalate; Sodium oxalate; Magnesium oxalate; Strontium oxalate; Barium oxalate; Iron(II) oxalate; Iron(III) oxalate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Copper(II) oxalate are inorganic compounds with the chemical formula CuC₂O₄(H₂O)_x. The value of x can be 0, 0.44, and 1. Two of these species are found as secondary minerals (degradation of minerals), whewellite (monohydrate) and moolooite (0.44 hydrate).^[3] The anhydrous compound has been characterized by X-ray crystallography.^[4] Many transition metal oxalate complexes are known.

Copper(II) monooxalates are practically insoluble in all solvents. They are coordination polymers.^[5]

Synthesis

Copper(II) oxalate can be produced by precipitation from acidified aqueous copper(II) salts and oxalic acid.^[6]^[7]

CuSO₄ + H₂C₂O₄ + H₂O → CuC₂O₄·H₂O + H₂SO₄

Reactions

Upon heating to 130 °C, the hydrated copper(II) oxalates convert to the anhydrous cupric oxalate. Further heating at higher temperatures under an atmosphere of hydrogen gives copper metal, suitable as a reagent.^[6]

The hydrates bind Lewis bases.

Hydrated copper(II) oxalate reacts with alkali metal oxalates and ammonium oxalate to give bis(oxalato)cuprate:^[8]

CuC₂O₄)(H₂O)_x + C₂O2−4 → [Cu(C₂O₄)₂]²⁻ + x H₂O

Uses

Copper oxalate is used as a catalyst for organic reactions, as a stabilizer for acetylated polyformaldehyde.^[9]^[10]

Related compounds

Cuprous oxalates.^[11]

References

^ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–188. ISBN 978-1138561632.
^ "Copper oxalate - Substance Information - ECHA". European Chemical Agency. Retrieved 17 June 2021.
^ Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel; Grivel, Jean-Claude (2014). "The Crystal structure of paramagnetic copper(<SCP>ii</SCP>) oxalate (CuC₂O₄): Formation and thermal decomposition of randomly stacked anisotropic nano-sized crystallites" (PDF). Dalton Trans. 43 (44): 16754–16768. doi:10.1039/C4DT01689K. PMID 25278188.
^ Schmittler, H. (1968). "Zum Strukturprinzip des fehlgeordneten Kupfer(II)-Oxalats CuC₂O₄·nH₂O". Monatsberichte der Deutschen Akademie der Wissenschaften zu Berlin. 10: 581-604.
^ "Hazardous Substances Data Bank (HSDB) : 265". National Library of Medicine. Retrieved 17 June 2021.
^ ^a ^b O. Glemser; R. Sauer (1963). "Copper(II) Sulfide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2pages=1017-1018. NY,NY: Academic Press.
^ Gooch, Frank Austin (1909). The precipitation of copper oxalate in analysis. p. 448. OCLC 890741677.
^ Kirschner, Stanley; McLean, John A.; Meerman, Gerardine (1960). "Potassium Dioxalatocuprate(II) 2-Hydrate". Inorganic Syntheses. Vol. 6. pp. 1–2. doi:10.1002/9780470132371.ch1. ISBN 978-0-470-13165-7.
^ Richardson, H. Wayne (1997). Handbook of Copper Compounds and Applications. CRC Press. p. 84. ISBN 978-0-8247-8998-5.
^ Richardson, H. Wayne (2000). "Copper Compounds". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a07_567. ISBN 978-3-527-30385-4.
^ Royappa, A. Timothy; Royappa, Andrew D.; Moral, Raphael F.; Rheingold, Arnold L.; Papoular, Robert J.; Blum, Deke M.; Duong, Tien Q.; Stepherson, Jacob R.; Vu, Oliver D.; Chen, Banghao; Suchomel, Matthew R.; Golen, James A.; André, Gilles; Kourkoumelis, Nikolaos; Mercer, Andrew D.; Pekarek, Allegra M.; Kelly, Dylan C. (November 2016). "Copper(I) oxalate complexes: Synthesis, structures and surprises". Polyhedron. 119: 563–574. doi:10.1016/j.poly.2016.09.043.

[crc-1] John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–188. ISBN 978-1138561632.

[2] "Copper oxalate - Substance Information - ECHA". European Chemical Agency. Retrieved 17 June 2021.

[3] Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel; Grivel, Jean-Claude (2014). "The Crystal structure of paramagnetic copper(<SCP>ii</SCP>) oxalate (CuC₂O₄): Formation and thermal decomposition of randomly stacked anisotropic nano-sized crystallites" (PDF). Dalton Trans. 43 (44): 16754–16768. doi:10.1039/C4DT01689K. PMID 25278188.

[4] Schmittler, H. (1968). "Zum Strukturprinzip des fehlgeordneten Kupfer(II)-Oxalats CuC₂O₄·nH₂O". Monatsberichte der Deutschen Akademie der Wissenschaften zu Berlin. 10: 581-604.

[5] "Hazardous Substances Data Bank (HSDB) : 265". National Library of Medicine. Retrieved 17 June 2021.

[Brauer-6] O. Glemser; R. Sauer (1963). "Copper(II) Sulfide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2pages=1017-1018. NY,NY: Academic Press.

[7] Gooch, Frank Austin (1909). The precipitation of copper oxalate in analysis. p. 448. OCLC 890741677.

[8] Kirschner, Stanley; McLean, John A.; Meerman, Gerardine (1960). "Potassium Dioxalatocuprate(II) 2-Hydrate". Inorganic Syntheses. Vol. 6. pp. 1–2. doi:10.1002/9780470132371.ch1. ISBN 978-0-470-13165-7.

[9] Richardson, H. Wayne (1997). Handbook of Copper Compounds and Applications. CRC Press. p. 84. ISBN 978-0-8247-8998-5.

[10] Richardson, H. Wayne (2000). "Copper Compounds". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a07_567. ISBN 978-3-527-30385-4.

[11] Royappa, A. Timothy; Royappa, Andrew D.; Moral, Raphael F.; Rheingold, Arnold L.; Papoular, Robert J.; Blum, Deke M.; Duong, Tien Q.; Stepherson, Jacob R.; Vu, Oliver D.; Chen, Banghao; Suchomel, Matthew R.; Golen, James A.; André, Gilles; Kourkoumelis, Nikolaos; Mercer, Andrew D.; Pekarek, Allegra M.; Kelly, Dylan C. (November 2016). "Copper(I) oxalate complexes: Synthesis, structures and surprises". Polyhedron. 119: 563–574. doi:10.1016/j.poly.2016.09.043.

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