Basic copper carbonate

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For the neutral compound, see Copper(II) carbonate.
Basic copper carbonate
Basic copper carbonate

Space-filling model of the formula unit of basic copper carbonate

Ball-and-stick model of part of the crystal structure of malachite, highlighting the formula unit
Names
IUPAC name
Dicopper carbonate dihydroxide
Other names
copper carbonate hydroxide, cupric carbonate, copper carbonate, Greenium
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.031.909 Edit this at Wikidata
UNII
  • InChI=1S/CH2O3.2Cu.2H2O/c2-1(3)4;;;;/h(H2,2,3,4);;;2*1H2/q;2*+2;;/p-4
    Key: ZMMDPCMYTCRWFF-UHFFFAOYSA-J
  • InChI=1/CH2O3.2Cu.2H2O/c2-1(3)4;;;;/h(H2,2,3,4);;;2*1H2/q;2*+2;;/p-4
    Key: ZMMDPCMYTCRWFF-XBHQNQODAP
  • C(=O)([O-])[O-].[OH-].[OH-].[Cu+2].[Cu+2]
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
7.08·10−9
Thermochemistry
88 J/mol·K
Std enthalpy of
formation
(ΔfH⦵298)
 −595 kJ/mol
Hazards
GHS labelling:
GHS07: Exclamation mark[1]
Warning
H302, H315, H319, H335[1]
P261, P305+P351+P338[1]
Lethal dose or concentration (LD, LC):
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 their standard state (at 25 °C [77 °F], 100 kPa).
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Basic copper carbonate is a chemical compound, more properly called copper(II) carbonate hydroxide. It is an

ionic compound (a salt) consisting of the ions copper(II) Cu2+
, carbonate CO2−
3, and hydroxide
OH−
.

The name most commonly refers to the compound with formula Cu
2CO
3(OH)2. It is a green crystalline solid that occurs in nature as the mineral malachite. It has been used since antiquity as a pigment, and it is still used as such in artist paints, sometimes called verditer, green bice, or mountain green.

Sometimes the name is used for Cu
3(CO
3)2(OH)2, a blue crystalline solid also known as the mineral azurite. It too has been used as pigment, sometimes under the name mountain blue or blue verditer.

Both 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.[3]

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.[4] It is decomposed by water or moisture from the air, and was synthesized only in 1973 by high temperature and very high pressures.[5]

Preparation

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

Basic copper carbonate is prepared by combining aqueous solutions of

ambient temperature and pressure. Basic copper carbonate precipitates from the solution, with release of carbon dioxide CO
2:[6]

Basic copper carbonate can also be prepared by reacting aqueous solutions of copper(II) sulfate and sodium bicarbonate at ambient conditions. Basic copper carbonate precipitates from the solution, again with release of carbon dioxide:

Copper(II) sulfate may also be substituted with Copper(II) chloride, creating Sodium chloride (NaCl) as a byproduct instead of Sodium sulfate (Na2SO4), both of which are soluble in water.

Reactions

Basic copper carbonate is decomposed by acids, such as solutions of hydrochloric acid HCl, into the copper(II) salt and carbon dioxide.

In 1794 the French chemist

cupric oxide.[7]

The basic copper carbonates, malachite and azurite, both decompose forming H2O, CO2, and CuO,

cupric oxide.[8]

Uses

Both malachite and azurite, as well as synthetic basic copper carbonate have been used as

lead-tin-yellow and yellow lake. The green color is achieved by mixing blue and yellow pigments.[12]

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.

References

  1. ^ a b c Copper(II) carbonate basic
  2. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0150". National Institute for Occupational Safety and Health (NIOSH).
  3. ISBN 08247-4878-6
  4. ISBN 0-12-352651-5
  5. ISSN 0044-2313
    .
  6. doi:10.1039/JR9270002883
  7. ISSN 0095-9367
    .
  8. ISSN 0040-6031
    .
  9. ISBN 978-0-7506-8980-9
  10. ^ Blue verditer, ColourLex
  11. ^ Robert L. Feller, Rubens’s: The Gerbier Family: Technical Examination of the Pigments and Paint Layers, Studies in the History of Art, Vol. 5 (1973), pp. 54–74.
  12. ^ Peter Paul Rubens, The Gerbier Family, ColourLex

External links

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