 | |
 | |
| Names | |
|---|---|
| IUPAC name Dicopper carbonate dihydroxide | |
| Other names copper carbonate hydroxide, cupric carbonate, copper carbonate | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.031.909 |
| UNII | |
| |
| |
| Properties | |
| Cu2(OH)2CO3 | |
| Molar mass | 221.114 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) | 7.08·10−9 |
| Thermochemistry | |
Std molar entropy(S⦵298) | 88 J/mol·K |
Std enthalpy of formation(ΔfH⦵298) | −595 kJ/mol |
| Hazards | |
| GHS labelling: | |
 [1] | |
| Warning | |
| H302,H315,H319,H335[1] | |
| P261,P305+P351+P338[1] | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 159 mg/kg (rat, oral) |
| NIOSH (US health exposure limits): | |
PEL (Permissible) | TWA 1 mg/m3 (as Cu)[2] |
REL (Recommended) | TWA 1 mg/m3 (as Cu)[2] |
IDLH (Immediate danger) | TWA 100 mg/m3 (as Cu)[2] |
| Safety data sheet (SDS) | Oxford MSDS |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Basic copper carbonate is a chemical compound, more properly calledcopper(II) carbonate hydroxide. It can be classified as acoordination polymer or asalt. It consists ofcopper(II) bonded tocarbonate andhydroxide with formulaCu2(CO3)(OH)2. It is a green solid that occurs in nature as the mineralmalachite. It has been used since antiquity as apigment, and it is still used as such in artist paints, sometimes calledverditer,green bice, ormountain green.[3]
Sometimes basic copper carbonate refers toCu
3(CO
3)2(OH)2, a blue crystalline solid also known as the mineralazurite. It too has been used as pigment, sometimes under the namemountain blue orblue verditer.
Bothmalachite andazurite can be found in theverdigrispatina that is found on weatheredbrass,bronze, andcopper. 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.[4]
This compound is often improperly called (even in chemistry articles)copper carbonate,cupric carbonate, and similar names. The true (neutral)copper(II) carbonate CuCO3 is not known to occur naturally.[5] It is decomposed by water or moisture from the air. It was synthesized only in 1973 by high temperature and very high pressures.[6]
Basic copper carbonate is prepared by combining aqueous solutions ofcopper(II) sulfate andsodium carbonate. Basic copper carbonate precipitates from the solution, with release ofcarbon dioxideCO
2:[7]
Basic copper carbonate can also be prepared by treating aqueous solutions ofcopper(II) sulfate withsodium bicarbonate.
Copper(II) sulfate may also be substituted withCopper(II) chloride.
Basic copper carbonate is decomposed by acids, such as solutions ofhydrochloric acidHCl, into the copper(II) salt and carbon dioxide.
In 1794 the French chemistJoseph Louis Proust (1754–1826) thermally decomposed copper carbonate to CO2 and CuO,cupric oxide.[8]
The basic copper carbonates, malachite and azurite, both decompose forming H2O, CO2, and CuO,cupric oxide.[9]
Basic copper carbonate is used to remove thiols and hydrogen sulfide from some gas streams, a process called "sweetening". Like many other copper compounds, it also has been used as analgaecide,wood preservative and similar applications. It is a precursor to various catalysts and copper soaps.[3]
Both malachite and azurite, as well as synthetic basic copper carbonate have been used aspigments.[10] One example of the use of bothazurite and its artificial form blue verditer[11] is the portrait of the family ofBalthazar Gerbier byPeter Paul Rubens.[12] The green skirt of Deborah Kip is painted inazurite,smalt, blue verditer (artificial form of azurite),yellow ochre,lead-tin-yellow and yellow lake. The green color is achieved by mixing blue and yellow pigments.[13]
