Basic copper carbonate
Names | |
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IUPAC name
Dicopper carbonate dihydroxide
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Other names
copper carbonate hydroxide, cupric carbonate, copper carbonate
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Identifiers | |
12069-69-1 | |
Properties | |
Cu2(OH)2CO3 | |
Molar mass | 221.116 g/mol |
Appearance | green powder |
Density | 4 g/cm3 |
Melting point | 200 °C (392 °F; 473 K) |
Boiling point | 290 °C (554 °F; 563 K) decomposes |
insoluble | |
Solubility product (Ksp)
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7.08·109 |
Thermochemistry | |
Std molar
entropy (S |
88 J/mol·K |
Std enthalpy of
formation (ΔfH |
−595 kJ/mol |
Vapor pressure | {{{value}}} |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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verify (what is ?) | |
Infobox references | |
Basic copper carbonate normally refers to the compound (Cu2(OH)2CO3) (the mineral malachite). Sometimes the name is used for Cu3(OH)2(CO3)2 (the related mineral azurite). Malachite and azurite can be found in the verdigris patina that is found on weathered brass, bronze, and copper. The composition of the patina can vary, in a maritime environment depending on the environment a basic chloride may be present, in an urban environment basic sulfates may be present.[1]
The compound Copper(II) carbonate CuCO3 is not known to occur naturally.[2] There is a report from 1973 of the production of CuCO3 from CuO or Cu3(CO3)2(OH)2 in the presence of carbon dioxide at 500 °C and 20 kb (2 GPa) pressure.[3] What is often called copper(II) carbonate or cupric carbonate is actually basic copper carbonate.
Preparation
Basic copper carbonate is prepared by combining aqueous solutions of copper(II) 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 (or filter) the above-mentioned solution; 1 minute at 6000 g is sufficient b) Wash the precipitate with distilled water and centrifuge or filter 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.
Reactions
"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. The basic copper carbonates, malachite and azurite, both decompose forming CO2 and CuO, cupric oxide.[4]
Uses
Both malachite and azurite basic copper carbonates have been used as pigments.[5] 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.[citation needed]
References
- ↑ Encyclopedia Of Corrosion Technology (Google eBook), Philip A. Schweitzer P.E.; CRC Press, 2004, ISBN 08247-4878-6
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- ↑ Valentine Walsh, Tracey Chaplin, Pigment Compendium: A Dictionary and Optical Microscopy of Historical Pigments, 2008, Routledge, ISBN 978-0-7506-8980-9
External links
Wikimedia Commons has media related to Copper(II) carbonate. |
H2CO3 | He | ||||||||||||||||
Li2CO3 | 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 |
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- Carbonates
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