Copper(Ii) Carbonate

Copper(II) carbonate
Names
	IUPAC name Copper(II) carbonate
	Other names Cupric carbonate, neutral copper carbonate
Identifiers
CAS Number	1184-64-1 [ECHA];
3D model (JSmol)	Interactive image;
ChemSpider	13799;
EC Number	214-671-4;
PubChem CID	14452;
UNII	9AOA5F11GJ ;
	InChI InChI=1S/CH2O3.Cu/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Key: GEZOTWYUIKXWOA-UHFFFAOYSA-L;
	SMILES C(=O)([O-])[O-].[Cu+2];
Properties
Chemical formula	CuCO3
Molar mass	123.5549
Appearance	green or blue Powder
Solubility in water	insoluble in water [clarification needed]
Solubility product (Ksp)	10−11.45 ± 0.10 at 25 °C.
Structure
Space group	Pa-C2s (7)
Lattice constant	a = 6.092 Å, b = 4.493 Å, c = 7.030 Å α = 90°, β = 101,34°°, γ = 90°
Coordination geometry	5
Hazards
Flash point	Non-flammable
Related compounds
Other anions	Copper(II) sulfate
Other cations	Nickel(II) carbonate; Zinc carbonate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
	(what is ?)
	Infobox references

Short description: Chemical compound

Copper(II) carbonate or cupric carbonate is a chemical compound with formula CuCO₃. At ambient temperatures, it is an ionic solid (a salt) consisting of copper(II) cations Cu²⁺ and carbonate anions CO2−3.

This compound is rarely encountered because it is difficult to prepare^[2] and readily reacts with water moisture from the air. The terms "copper carbonate", "copper(II) carbonate", and "cupric carbonate" almost always refer (even in chemistry texts) to a basic copper carbonate (or copper(II) carbonate hydroxide), such as Cu₂(OH)₂CO₃ (which occurs naturally as the mineral malachite) or Cu₃(OH)₂(CO₃)₂ (azurite). For this reason, the qualifier neutral may be used instead of "basic" to refer specifically to CuCO₃.

Preparation

Reactions that may be expected to yield CuCO₃, such as mixing solutions of copper(II) sulfate CuSO₄ and sodium carbonate Na₂CO₃ in ambient conditions, yield instead a basic carbonate and CO₂, due to the great affinity of the Cu²⁺ ion for the hydroxide anion HO⁻.^[5]

Thermal decomposition of the basic carbonate at atmospheric pressure yields copper(II) oxide CuO rather than the carbonate.

In 1960, C. W. F. T. Pistorius claimed synthesis by heating basic copper carbonate at 180 °C in an atmosphere of carbon dioxide CO₂ (450 atm) and water (50 atm) for 36 hours. The bulk of the products was well-crystallized malachite Cu₂CO₃(OH)₂, but a small yield of a rhombohedral substance was also obtained, claimed to be CuCO₃.^[6] However, this synthesis was apparently not reproduced.^[2]

Reliable synthesis of true copper(II) carbonate was reported for the first time in 1973 by Hartmut Ehrhardt and others. The compound was obtained as a gray powder, by heating basic copper carbonate in an atmosphere of carbon dioxide (produced by the decomposition of silver oxalate Ag₂C₂O₄) at 500 °C and 2 GPa (20,000 atm). The compound was determined to have a monoclinic structure.^[7]

Chemical and physical properties

The stability of dry CuCO₃ depends critically on the partial pressure of carbon dioxide (p_CO₂). It is stable for months in dry air, but decomposes slowly into CuO and CO₂ if p_CO₂ is less than 0.11 atm.^[3]

In the presence of water or moist air at 25 °C, CuCO₃ is stable only for p_CO₂ above 4.57 atmospheres and pH between about 4 and 8.^[8] Below that partial pressure, it reacts with water to form a basic carbonate (azurite, Cu₃(CO₃)₂(OH)₂).^[3]

3 CuCO₃ + H₂O → Cu₃(CO₃)₂(OH)₂ + CO₂

In highly basic solutions, the complex anion Cu(CO₃)2−2 is formed instead.^[3]

The solubility product of the true copper(II) carbonate was measured by Reiterer and others as pK_so = 11.45 ± 0.10 at 25 °C.^[2]^[3]^[4]

Structure

In the crystal structure of CuCO₃, copper adopts a distorted square pyramidal coordination environment with coordination number 5. Each carbonate ion bonds to 5 copper centres.^[1]

Unit cell of CuCO₃
Copper coordination environment
Carbonate coordination environment

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 H. Seidel, H. Ehrhardt, K. Viswanathan, W. Johannes (1974): "Darstellung, Struktur und Eigenschaften von Kupfer(II)-Carbonat". Z. anorg. allg. Chem., volume 410, pages 138-148. doi:10.1002/zaac.19744100207
↑ ^2.0 ^2.1 ^2.2 ^2.3 Rolf Grauer (1999) "Solubility Products of M(II) Carbonates ". Technical Report NTB-99-03, NAGRA - National Cooperative for the Disposal of Radioactive Waste; pages 8, 14, and 17. Translated by U. Berner.
↑ ^3.0 ^3.1 ^3.2 ^3.3 ^3.4 F. Reiterer, W. Johannes, H. Gamsjäger (1981): "Semimicro Determination of Solubility Constants: Copper(II) Carbonate and Iron(II) Carbonate". Mikrochim. Acta, volume 1981, page 63. doi:10.1007/BF01198705
↑ ^4.0 ^4.1 F. Reiterer (1980): "Löslichkeitskonstanten und Freie Bildungsenthalpien neutraler Übergangsmetallcarbonate". Thesis, Montanuniversität Leoben.
↑ Ahmad, Zaki (2006). Principles of Corrosion Engineering and Corrosion Control. Oxford: Butterworth-Heinemann. pp. 120–270. ISBN 9780750659246.
↑ C. W. F. T. Pistorius (1960): "Synthesis at High Pressure and Lattice Constants of Normal Cupric Carbonate". Experientia, volume XVI, page 447-448. doi:10.1007/BF02171142
↑ Hartmut Erhardt, Wilhelm Johannes, and Hinrich Seidel (1973): "Hochdrucksynthese von Kupfer(II)-Carbonat", Z. Naturforsch., volume 28b, issue 9-10, page 682. doi:10.1515/znb-1973-9-1021
↑ H. Gamsjäger and W. Preis (1999): "Copper Content in Synthetic Copper Carbonate." Letter to J. Chem. Educ., volume 76, issue 10, page 1339. doi:10.1021/ed076p1339.1

Carbonates
H₂CO₃																	He
Li₂CO₃, LiHCO₃	BeCO₃											B	C	(NH₄)₂CO₃, NH₄HCO₃	O	F	Ne
Na₂CO₃, NaHCO₃, Na₃H(CO₃)₂	MgCO₃, Mg(HCO₃)₂											Al₂(CO₃)₃	Si	P	S	Cl	Ar
K₂CO₃, KHCO₃	CaCO₃, Ca(HCO₃)₂	Sc	Ti	V	Cr	MnCO₃	FeCO₃	CoCO₃	NiCO₃	CuCO₃	ZnCO₃	Ga	Ge	As	Se	Br	Kr
Rb₂CO₃	SrCO₃	Y	Zr	Nb	Mo	Tc	Ru	Rh	Pd	Ag₂CO₃	CdCO₃	In	Sn	Sb	Te	I	Xe
Cs₂CO₃, CsHCO₃	BaCO₃		Hf	Ta	W	Re	Os	Ir	Pt	Au	Hg	Tl₂CO₃	PbCO₃	(BiO)₂CO₃	Po	At	Rn
Fr	Ra		Rf	Db	Sg	Bh	Hs	Mt	Ds	Rg	Cn	Nh	Fl	Mc	Lv	Ts	Og
		↓
		La₂(CO₃)₃	Ce₂(CO₃)₃	Pr	Nd	Pm	Sm	Eu	Gd	Tb	Dy	Ho	Er	Tm	Yb	Lu
		Ac	Th	Pa	UO₂CO₃	Np	Pu	Am	Cm	Bk	Cf	Es	Fm	Md	No	Lr

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Original source: https://en.wikipedia.org/wiki/Copper(II) carbonate. Read more

[seidel-1] 1.0 ^1.1 ^1.2 ^1.3 H. Seidel, H. Ehrhardt, K. Viswanathan, W. Johannes (1974): "Darstellung, Struktur und Eigenschaften von Kupfer(II)-Carbonat". Z. anorg. allg. Chem., volume 410, pages 138-148. doi:10.1002/zaac.19744100207

[grauer-2] 2.0 ^2.1 ^2.2 ^2.3 Rolf Grauer (1999) "Solubility Products of M(II) Carbonates ". Technical Report NTB-99-03, NAGRA - National Cooperative for the Disposal of Radioactive Waste; pages 8, 14, and 17. Translated by U. Berner.

[reit81-3] 3.0 ^3.1 ^3.2 ^3.3 ^3.4 F. Reiterer, W. Johannes, H. Gamsjäger (1981): "Semimicro Determination of Solubility Constants: Copper(II) Carbonate and Iron(II) Carbonate". Mikrochim. Acta, volume 1981, page 63. doi:10.1007/BF01198705

[reit80-4] 4.0 ^4.1 F. Reiterer (1980): "Löslichkeitskonstanten und Freie Bildungsenthalpien neutraler Übergangsmetallcarbonate". Thesis, Montanuniversität Leoben.

[5] Ahmad, Zaki (2006). Principles of Corrosion Engineering and Corrosion Control. Oxford: Butterworth-Heinemann. pp. 120–270. ISBN 9780750659246.

[pistorius-6] C. W. F. T. Pistorius (1960): "Synthesis at High Pressure and Lattice Constants of Normal Cupric Carbonate". Experientia, volume XVI, page 447-448. doi:10.1007/BF02171142

[erhardt-7] Hartmut Erhardt, Wilhelm Johannes, and Hinrich Seidel (1973): "Hochdrucksynthese von Kupfer(II)-Carbonat", Z. Naturforsch., volume 28b, issue 9-10, page 682. doi:10.1515/znb-1973-9-1021

[gams-8] H. Gamsjäger and W. Preis (1999): "Copper Content in Synthetic Copper Carbonate." Letter to J. Chem. Educ., volume 76, issue 10, page 1339. doi:10.1021/ed076p1339.1

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
Cu(I,II)	Cu₃H₄O₈S₂
Cu(II)	Cu(BF₄)₂ CuBr₂ CuC₂ CuCO₃ Cu(CN)₂ Cu(ClO₃)₂ CuCl₂ CuF₂ Cu(NO₃)₂ Cu₃(PO₄)₂ Cu(N₃)₂ CuO CuO₂ Cu(OH)₂ CuI₂ CuS CuSO₄ Cu₃(AsO₄)₂
Cu(III)	K₃CuF₆ Cu₂O₃
Cu(IV)	Cs₂CuF₆ Rb₂CuF₆