Chemistry:Copper oxalate

Copper oxalate

Names
Other names Copper (II) oxalate, cupric oxalate, copper(2+) ethanedioate
Identifiers
CAS Number	814-91-5 Y hemihydrate: 55671-32-4
3D model (JSmol)	Interactive image
ChemSpider	12596
EC Number	212-411-4
PubChem CID	54602330
UNII	BN136S94FS N
UN number	3077
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	CuC2O4
Molar mass	151.56
Appearance	blue-white solid (as a hemihydrate)
Melting point	310 °C (590 °F; 583 K)
Solubility in water	insoluble
Solubility product (Ksp)	4.43×10−10
Hazards
GHS pictograms
GHS Signal word	Warning
GHS hazard statements	H302+312Category:GHS errors, H302, H312
GHS precautionary statements	P264, P270, P280, P301+312, P302+352, 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 Lithium oxalate Praseodymium oxalate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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Copper oxalate is an inorganic compound, a salt of copper metal and oxalic acid with the chemical formula CuC₂O₄. The compound is practically insoluble in water, alcohol, ether, and acetic acid but soluble in ammonium hydroxide. Copper oxalate forms a hydrate, which forms acid-blue crystals.

Synthesis

Copper oxalate can be produced by precipitation from a mixture of a copper (II) salt and a sodium oxalate solution or by reacting copper sulfate with oxalic acid.

$\mathsf{C}\mathsf{u}\mathsf{S}{\mathsf{O}}_{\mathsf{4}}\mathsf{+}{\mathsf{H}}_{\mathsf{2}}{\mathsf{C}}_{\mathsf{2}}{\mathsf{O}}_{\mathsf{4}}\mathsf{+}{\mathsf{H}}_{\mathsf{2}}\mathsf{O}\stackrel{}{\to }\mathsf{C}\mathsf{u}{\mathsf{C}}_{\mathsf{2}}{\mathsf{O}}_{\mathsf{4}}\mathsf{\cdot }{\mathsf{H}}_{\mathsf{2}}\mathsf{O}\mathsf{\downarrow }\mathsf{+}{\mathsf{H}}_{\mathsf{2}}\mathsf{S}{\mathsf{O}}_{\mathsf{4}}$

Properties

As a hemihydrate, copper oxalate is a blue-white solid that is practically insoluble in water. At 200 °C, it loses its water of crystallization.

The compound also forms complex salts with alkali metal oxalates and ammonium oxalate:

$\mathsf{C}\mathsf{u}{\mathsf{C}}_{\mathsf{2}}{\mathsf{O}}_{\mathsf{4}}\mathsf{+}{\mathsf{K}}_{\mathsf{2}}{\mathsf{C}}_{\mathsf{2}}{\mathsf{O}}_{\mathsf{4}}\mathsf{+}\mathsf{2}{\mathsf{H}}_{\mathsf{2}}\mathsf{O}\stackrel{}{\to }{\mathsf{K}}_{\mathsf{2}}\mathsf{[}\mathsf{C}\mathsf{u}\mathsf{(}{\mathsf{C}}_{\mathsf{2}}{\mathsf{O}}_{\mathsf{4}}{\mathsf{)}}_{\mathsf{2}}\mathsf{]}\mathsf{\cdot }\mathsf{2}{\mathsf{H}}_{\mathsf{2}}\mathsf{O}$

Uses

Copper oxalate is used as a catalyst for organic reactions, as a stabilizer for acetylated polyformaldehyde and in seed treatment (to repel birds and rodents).

See also

• Moolooite
• Antipinite