Basic copper carbonate

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Basic copper carbonate
Copper carbonate basic.jpg
Malachite-formula-unit-and-coordination-fade-25-from-xtal-3D-bs-17-25.png
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 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
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
Appearancegreen 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
Std molar
entropy
(S298)
88 J/mol·K
−595 kJ/mol
Hazards
GHS labelling:
GHS-pictogram-exclam.svg [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 can be classified as a coordination polymer or a salt. It consists of copper(II) bonded to carbonate and hydroxide with formula Cu2(CO3)(OH)2. It is a green 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. [3]

Contents

Sometimes basic copper carbonate refers to 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. [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]

Preparation

Basic copper(II) carbonate patina on roofs of Chateau Frontenac. Chateau Frontenac2010 crop roofs.jpg
Basic copper(II) carbonate patina on roofs of Château Frontenac.

Basic copper carbonate is prepared by combining aqueous solutions of copper(II) sulfate and sodium carbonate. Basic copper carbonate precipitates from the solution, with release of carbon dioxide CO
2
: [7]

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

Basic copper carbonate can also be prepared by treating aqueous solutions of copper(II) sulfate with sodium bicarbonate.

Copper(II) sulfate may also be substituted with Copper(II) chloride.

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 Joseph 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]

Uses

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 an algaecide, 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 as pigments. [10] One example of the use of both azurite and its artificial form blue verditer [11] is the portrait of the family of Balthasar Gerbier by Peter Paul Rubens. [12] The green skirt of Deborah Kip is painted in azurite, 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]

Related Research Articles

Benedict's reagent is a chemical reagent and complex mixture of sodium carbonate, sodium citrate, and copper(II) sulfate pentahydrate. It is often used in place of Fehling's solution to detect the presence of reducing sugars. The presence of other reducing substances also gives a positive result. Such tests that use this reagent are called the Benedict's tests. A positive test with Benedict's reagent is shown by a color change from clear blue to brick-red with a precipitate.

<span class="mw-page-title-main">Malachite</span> Mineral variety of copper carbonate

Malachite is a copper carbonate hydroxide mineral, with the formula Cu2CO3(OH)2. This opaque, green-banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures and deep, underground spaces, where the water table and hydrothermal fluids provide the means for chemical precipitation. Individual crystals are rare, but occur as slender to acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur.

<span class="mw-page-title-main">Azurite</span> Copper carbonate mineral

Azurite is a soft, deep-blue copper mineral produced by weathering of copper ore deposits. During the early 19th century, it was also known as chessylite, after the type locality at Chessy-les-Mines near Lyon, France. The mineral, a basic carbonate with the chemical formula Cu3(CO3)2(OH)2, has been known since ancient times, and was mentioned in Pliny the Elder's Natural History under the Greek name kuanos (κυανός: "deep blue," root of English cyan) and the Latin name caeruleum. Copper (Cu2+) gives it its blue color.

<span class="mw-page-title-main">Copper(II) sulfate</span> Chemical compound

Copper(II) sulfate is an inorganic compound with the chemical formula CuSO4. It forms hydrates CuSO4·nH2O, where n can range from 1 to 7. The pentahydrate (n = 5), a bright blue crystal, is the most commonly encountered hydrate of copper(II) sulfate, while its anhydrous form is white. Older names for the pentahydrate include blue vitriol, bluestone, vitriol of copper, and Roman vitriol. It exothermically dissolves in water to give the aquo complex [Cu(H2O)6]2+, which has octahedral molecular geometry. The structure of the solid pentahydrate reveals a polymeric structure wherein copper is again octahedral but bound to four water ligands. The Cu(II)(H2O)4 centers are interconnected by sulfate anions to form chains.

<span class="mw-page-title-main">Copper(II) oxide</span> Chemical compound – an oxide of copper with formula CuO

Copper(II) oxide or cupric oxide is an inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu2O or copper(I) oxide (cuprous oxide). As a mineral, it is known as tenorite. It is a product of copper mining and the precursor to many other copper-containing products and chemical compounds.

Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find the elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution, therefore materials in other forms may need to be brought to this state before using standard methods. The solution is then treated with various reagents to test for reactions characteristic of certain ions, which may cause color change, precipitation and other visible changes.

Copper carbonate may refer to :

<span class="mw-page-title-main">Copper(II) hydroxide</span> Hydroxide of copper

Copper(II) hydroxide is the hydroxide of copper with the chemical formula of Cu(OH)2. It is a pale greenish blue or bluish green solid. Some forms of copper(II) hydroxide are sold as "stabilized" copper(II) hydroxide, although they likely consist of a mixture of copper(II) carbonate and hydroxide. Cupric hydroxide is a strong base, although its low solubility in water makes this hard to observe directly.

<span class="mw-page-title-main">Copper(II) acetate</span> Chemical compound

Copper(II) acetate, also referred to as cupric acetate, is the chemical compound with the formula Cu(OAc)2 where AcO is acetate (CH
3
CO
2
). The hydrated derivative, Cu2(OAc)4(H2O)2, which contains one molecule of water for each copper atom, is available commercially. Anhydrous copper(II) acetate is a dark green crystalline solid, whereas Cu2(OAc)4(H2O)2 is more bluish-green. Since ancient times, copper acetates of some form have been used as fungicides and green pigments. Today, copper acetates are used as reagents for the synthesis of various inorganic and organic compounds. Copper acetate, like all copper compounds, emits a blue-green glow in a flame.

A spectator ion is an ion that exists both as a reactant and a product in a chemical equation of an aqueous solution.

<span class="mw-page-title-main">Biuret test</span> Chemical test for detecting peptide bonds

In chemistry, the Biuret test, also known as Piotrowski's test, is a chemical test used for detecting the presence of at least two peptide bonds in a molecule. In the presence of peptides, a copper(II) ion forms mauve-colored coordination complexes in an alkaline solution. The reaction was first observed in 1833; In Poland, the biuret test is also known as Piotrowski's test in honor of the Polish physiologist Gustaw Piotrowski who independently rediscovered it in 1857. Several variants on the test have been developed, such as the BCA test and the Modified Lowry test.

<span class="mw-page-title-main">Copper(II) phosphate</span> Chemical compound

Copper(II) phosphate are inorganic compounds with the formula Cu3(PO4)2. They can be regarded as the cupric salts of phosphoric acid. Anhydrous copper(II) phosphate and a trihydrate are blue solids.

<span class="mw-page-title-main">Dicopper chloride trihydroxide</span> Chemical compound

Dicopper chloride trihydroxide is the chemical compound with the chemical formula Cu2(OH)3Cl. It is often referred to as tribasic copper chloride (TBCC), copper trihydroxyl chloride or copper hydroxychloride. It is a greenish crystalline solid encountered in mineral deposits, metal corrosion products, industrial products, art and archeological objects, and some living systems. It was originally manufactured on an industrial scale as a precipitated material used as either a chemical intermediate or a fungicide. Since 1994, a purified, crystallized product has been produced at the scale of thousands of tons per year, and used extensively as a nutritional supplement for animals.

<span class="mw-page-title-main">Copper(II) carbonate</span> Chemical compound

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

<span class="mw-page-title-main">Blue pigments</span> Natural or synthetic materials

Blue pigments are natural or synthetic materials, usually made from minerals and insoluble with water, used to make the blue colors in painting and other arts. The raw material of the earliest blue pigment was lapis lazuli from mines in Afghanistan, that was refined into the pigment ultramarine. Since the late 18th and 19th century, blue pigments are largely synthetic, manufactured in laboratories and factories.

<span class="mw-page-title-main">Green pigments</span> Substances reflecting light between 475-590 nm

Green pigments are the materials used to create the green colors seen in painting and the other arts. Most come from minerals, particularly those containing compounds of copper. Green pigments reflect the green portions of the spectrum of visible light, and absorb the others. Important green pigments in art history include Malachite and Verdigris, found in tomb paintings in Ancient Egypt, and the Green earth pigments popular in the Middle Ages. More recent greens, such as Cobalt Green, are largely synthetic, made in laboratories and factories.

<span class="mw-page-title-main">Copper compounds</span> Chemical compounds containing copper

Copper forms a rich variety of compounds, usually with oxidation states +1 and +2, which are often called cuprous and cupric, respectively. Copper compounds, whether organic complexes or organometallics, promote or catalyse numerous chemical and biological processes.

<span class="mw-page-title-main">Azurite (pigment)</span> Blue pigment commonly used in the Middle Ages and Renaissance

Azurite is an inorganic pigment derived from the mineral of the same name. It was likely used by artists as early as the Fourth Dynasty in Egypt, but it was less frequently employed than synthetically produced copper pigments such as Egyptian Blue. In the Middle Ages and Renaissance, it was the most prevalent blue pigment in European paintings, appearing more commonly than the more expensive ultramarine. Azurite's derivation from copper mines tends to give it a greenish hue, in contrast with the more violet tone of ultramarine. Azurite is also less stable than ultramarine, and notable paintings such as Michelangelo's The Entombment have seen their azure blues turn to olive green in time. Azurite pigment typically includes traces of malachite and cuprite; both minerals are found alongside azurite in nature, and they may account for some of the green discoloration of the pigment. The particle size of azurite pigment has been shown to have a significant effect on its chromatic intensity, and the manner of grinding and preparing the pigment therefore has a major impact on its appearance.

References

  1. 1 2 3 Copper(II) carbonate basic
  2. 1 2 3 NIOSH Pocket Guide to Chemical Hazards. "#0150". National Institute for Occupational Safety and Health (NIOSH).
  3. 1 2 Zhang, Jun; Richardson, H. Wayne (2016). "Copper Compounds". Ullmann's Encyclopedia of Industrial Chemistry. pp. 1–31. doi:10.1002/14356007.a07_567.pub2. ISBN   978-3-527-30673-2.
  4. Encyclopedia Of Corrosion Technology (Google eBook), Philip A. Schweitzer P.E.; CRC Press, 2004, ISBN   08247-4878-6
  5. Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, p. 1263, ISBN   0-12-352651-5
  6. Seidel, H.; Ehrhardt, H.; Viswanathan, K.; Johannes, W. (1974). "Darstellung, Struktur und Eigenschaften von Kupfer(II)-Carbonat". Zeitschrift für anorganische und allgemeine Chemie. 410 (2): 138–148. doi:10.1002/zaac.19744100207. ISSN   0044-2313.
  7. Jack Reginald Irons Hepburn (1927): "The chemical nature of precipitated basic cupric carbonate". Article CCCLXXXVI, Journal of the Chemical Society (Resumed), volume 1927, pp. 2883–2896. doi : 10.1039/JR9270002883
  8. Kapoor, Satish C. (1965). "Berthollet, Proust, and Proportions". Chymia. 10: 53–110. doi:10.2307/27757247. ISSN   0095-9367.
  9. Brown, I.W.M.; Mackenzie, K.J.D.; Gainsford, G.J. (1984). "Thermal decomposition of the basic copper carbonates malachite and azurite". Thermochimica Acta. 75 (1–2): 23–32. doi:10.1016/0040-6031(84)85003-0. ISSN   0040-6031.
  10. Valentine Walsh, Tracey Chaplin, Pigment Compendium: A Dictionary and Optical Microscopy of Historical Pigments, 2008, Routledge, ISBN   978-0-7506-8980-9
  11. Blue verditer, ColourLex
  12. 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.
  13. Peter Paul Rubens, The Gerbier Family, ColourLex