Copper(II) carbonate

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Copper(II) carbonate
Copper (II) carbonate
Identifiers
CAS number 1184-64-1 YesY
PubChem 14452
ChemSpider 13799 YesY
RTECS number FF950000
Jmol-3D images Image 1
Properties
Molecular formula CuCO
3
Molar mass 123.555 g/mol
Appearance green powder
Density 3.9 g/cm3
Melting point 200 °C (392 °F; 473 K)
Boiling point 290 °C (554 °F; 563 K) decomposes
Solubility in water insoluble
Solubility product, Ksp 7.08·109
Solubility soluble in acetic acid
Thermochemistry
Std molar
entropy
So298
88 J/mol·K
Std enthalpy of
formation
ΔfHo298
−595 kJ/mol
Hazards
MSDS Oxford MSDS
GHS pictograms The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)[1]
GHS signal word Warning
GHS hazard statements H302, H315, H319, H335[1]
GHS precautionary statements P261, P305+351+338[1]
EU classification Harmful Xn
R-phrases R22, R36/37/38
S-phrases S26, S36
LD50 159 mg/kg (rat, oral)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Copper(II) carbonate (often called copper carbonate or cupric carbonate) is a blue-green compound (chemical formula CuCO3) forming part of the verdigris patina that is found on weathered brass, bronze, and copper. The colour can vary from bright blue to green, because there may be a mixture of both copper carbonate and basic copper carbonate in various stages of hydration.

Reactions[edit]

Copper carbonate was the first compound to be broken down into several, separate elements (copper, carbon, and oxygen). It was broken down in 1794 by the French chemist Joseph Louis Proust (1754–1826). When heated, it thermally decomposes to form CO2 and CuO, cupric oxide, a black solid.

Copper in moist air slowly acquires a dull green coating because its top layer has oxidised with the air. Some architects use this material on rooftops for this interesting colour. The green material is a 1:1 mole mixture of Cu(OH)2 and CuCO3:[2]

2 Cu(s) + H2O(g) + CO2 + O2 → Cu(OH)2 + CuCO3(s)

Copper carbonate decomposes at 290 °C, giving off carbon dioxide and leaving copper(II) oxide:

CuCO3(s) → CuO(s) + CO2(g)

Basic copper(II) carbonate occurs naturally as malachite (Cu2(OH)2CO3) and azurite (Cu3(OH)2(CO3)2).

Copper(II) carbonate crystal structure

Preparation[edit]

Basic copper carbonate is prepared by combining aqueous solutions of copper sulfate and sodium carbonate. Basic copper carbonate precipitates from the solution:

2 CuSO4 + 2 Na2CO3 + H2O → Cu2(OH)2CO3 + 2 Na2SO4 + CO2

The formation of basic copper carbonate can be verified in the following steps: a) Centrifuge the above-mentioned solution, 1 minute at 6000 g is sufficient b) Wash the precipitate with distilled water and centrifuge again c) The colour of the precipitate is blue, like that of several copper salts but none of the sodium salts d) If dilute (1M) hydrochloric acid is added, then bubbles of CO2 will emerge and the precipitate will be fully solubilised. These would not be formed if dilute hydrochloric acid was added to solid Na2SO4.

Basic copper(II) carbonate patina on roofs of Château Frontenac.

Copper carbonate, CuCO3 is obtained from basic copper carbonate, CuO or Cu3(CO3)2(OH)2 in the presence of carbon dioxide at 500 °C and 20 kb (2 GPa) pressure.[3]

Uses[edit]

It was formerly much used as a pigment, and is still in use for artist's colours. It has also been used in some types of make-up, like lipstick, although it can also be toxic to humans. It also has been used for many years as an effective algaecide in farm ponds and in aquaculture operations.

References[edit]

  1. ^ a b c Copper(II) carbonate
  2. ^ Masterson, W. L., & Hurley, C. N. (2004). Chemistry: Principles and Reactions, 5th Ed. Thomson Learning, Inc. (p 498).
  3. ^ Seidel, H.; Ehrhardt, H.; Viswanathan, K.; Johannes, W. (1974). "Darstellung, Struktur und Eigenschaften von Kupfer(II)-Carbonat". Zeitschrift fur anorganische und allgemeine Chemie 410 (2): 138–148. doi:10.1002/zaac.19744100207. ISSN 0044-2313. 

External links[edit]


H2CO3 He
LiCO3 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 Uut Fl Uup Lv Uus Uuo
La2(CO3)3 Ce 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