COPPER CARBONATE

Copper carbonate is an inorganic copper(II) compound commercially supplied most often as basic copper carbonate, a green powder with the composition CuCO₃·Cu(OH)₂.
It serves as a copper source in ceramic glazes, pigments, chemical manufacture, catalyst preparation, and certain formulated wood preservatives.
Its practical functions arise from its color, its reaction with acids, and its conversion to copper oxide when heated. 

CAS Number: 12069-69-1
EC Number: 235-113-6
Molecular Formula: Cu₂CO₃(OH)₂
Molecular Weight: 221.12 g/mol

Synonyms: Basic copper carbonate, Copper carbonate basic, Copper(II) carbonate basic, Basic copper(II) carbonate, Basic cupric carbonate, Cupric carbonate basic, Copper(II) hydroxide carbonate, Copper(II) carbonate hydroxide, Copper hydroxide carbonate, Copper hydroxycarbonate, Copper(II) carbonate dihydroxide, Copper dihydroxide carbonate, Dicopper carbonate dihydroxide, Dicopper dihydroxycarbonate, Copper(II) carbonate–copper(II) hydroxide (1:1), Copper(2+) carbonate hydroxide (2:1:2), Carbonic acid copper(2+) salt (1:1) basic, (Carbonato)dihydroxydicopper, (Carbonato(2−))dihydroxydicopper, Copper (carbonato)dihydroxydi-, Basic Copper Carbonate, Copper Carbonate Basic, Copper(II) Carbonate Basic, Basic Copper(II) Carbonate, Copper(II) Basic Carbonate, Cupric Carbonate Basic, Basic Cupric Carbonate, Cupric Basic Carbonate, Copper Basic Carbonate, Copper(II) Carbonate Hydroxide, Copper(II) Hydroxide Carbonate, Copper Carbonate Hydroxide, Copper Hydroxide Carbonate, Cupric Carbonate Hydroxide, Cupric Hydroxide Carbonate, Dicopper Carbonate Dihydroxide, Dicopper Dihydroxide Carbonate, Copper(II) Carbonate Dihydroxide, Copper Dihydroxide Carbonate, Dicopper Dihydroxycarbonate, Carbonatodihydroxodicopper, Copper (Carbonato)Dihydroxydi-, Copper [μ-[Carbonato(2−)-O:O′]]Dihydroxydi-, Copper(II) Carbonate–Copper(II) Hydroxide (1:1), Copper(II) Carbonate Copper(II) Hydroxide (1:1), Carbonic Acid Copper(2+) Salt (1:1) Basic, Carbonic Acid Copper Complex, Copper(2+) Carbonate Hydroxide (2:1:2), Copper(II) Carbonate Hydroxide (2:1:2), Green Hydrous Copper Carbonate, Hydrated Basic Copper Carbonate

APPLICATIONS

Ceramic glazes

Copper carbonate supplies copper to ceramic glazes, where it can produce green and blue-green colors depending on the glaze composition and firing conditions.
The basic carbonate decomposes during firing, and the copper enters the developing glaze melt rather than remaining as intact green powder.
Copper concentration, glaze chemistry, and kiln atmosphere together determine the final appearance, so the same addition can yield different results in different recipes.
Copper carbonate can disperse through a glaze slurry in a way that helps limit concentrated dark specks in the fired surface.
Its decomposition also releases gas, which may contribute to pinholes or blisters if the glaze seals before bubbles escape.
A glaze intended for food-contact ware requires assessment of the finished fired surface, including its resistance to copper release; the raw ingredient alone cannot establish suitability. 

Pigments and decorative materials

Copper carbonate provides a green copper-containing material for selected pigment and decorative applications.
When incorporated as a powder, its apparent shade depends on particle characteristics, dispersion, and the surrounding binder or medium.
It can also act as a precursor to other copper pigments whose color develops only after further chemical or thermal processing.
Copper carbonate pigments have historical connections with green copper minerals, particularly malachite.
A manufactured basic copper carbonate powder and a prepared mineral pigment may share the same nominal composition while differing in particle size, impurities, and visual character.
These differences matter when matching color, opacity, and handling behavior in a specific decorative formulation.

Copper salts and chemical intermediates

Copper carbonate reacts with acids to form the corresponding copper(II) salts while releasing carbon dioxide and water.
This makes it a copper source for preparing selected solutions and solid compounds without introducing the counter-ion of a pre-existing soluble copper salt.
The acid chosen determines the product, while reaction control and subsequent purification determine its final composition.
Copper carbonate can also enter processes that produce copper-containing organic salts and other specialty intermediates.
Because the powder has low water solubility, many such reactions proceed through contact between solid particles and the reacting liquid.
Particle size, mixing, acid addition, and removal of insoluble impurities influence the rate and consistency of conversion. 

Copper oxide and catalyst preparation

Copper carbonate provides a route to copper(II) oxide through controlled heating.
Its carbonate and hydroxide components release carbon dioxide and water as the starting material converts to the oxide.
This transformation is useful when a process calls for copper oxide with physical characteristics developed from a prepared carbonate precursor.
Copper carbonate can also serve as a precursor in the manufacture of copper-containing catalysts.
Precipitation conditions influence the precursor’s particle structure and distribution, while later heating and processing shape the resulting catalytic material.
The activity belongs to the finished catalyst system and cannot be inferred from the presence of copper carbonate alone. 

Wood-preservative formulations

Basic copper carbonate is an active copper source in certain formulated wood preservatives.
In these products, copper contributes to protection against organisms that cause wood deterioration, while the complete formulation determines how the copper is distributed and retained.
Some systems incorporate finely divided particles; others involve processing that changes how copper is delivered into the wood.
Wood-preservative performance depends on formulation, treatment method, retention, and the intended exposure of the treated wood.
A copper carbonate powder is not itself a ready-to-apply preservative with an established treatment rate.
Use in a finished preservative is subject to the applicable product authorization and label conditions.

Laboratory and process chemistry

Copper carbonate offers a visible example of an acid–carbonate reaction in laboratory work.
Adding a suitable acid produces carbon dioxide as the solid dissolves and forms a copper-containing solution.
The reaction illustrates both the carbonate component and the distinction between a largely insoluble starting powder and a soluble product.
Copper carbonate also provides a starting material for preparing copper compounds on a controlled scale.
Its measured copper content and relatively straightforward conversion to copper oxide make it useful in material-preparation work.
Results depend on the actual grade, since moisture, residual salts, and particle characteristics can differ between powders. 

DESCRIPTION

Identity and composition

Copper carbonate in this profile means the commercial basic copper(II) carbonate identified by CAS Number 12069-69-1.
Its composition is written Cu₂CO₃(OH)₂ or CuCO₃·Cu(OH)₂, showing two copper atoms, one carbonate group, and two hydroxide groups per formula unit.
It should be distinguished from the simple carbonate CuCO₃ and from basic copper carbonates with a different copper-to-carbonate ratio. sigmaaldrich.com
The expression CuCO₃·Cu(OH)₂ describes composition; it does not mean that a well-characterized sample must be treated as a loose physical blend of two separate powders.
The same nominal composition occurs in the mineral malachite, although commercial precipitated material need not have the mineral’s appearance or particle structure.
Blue azurite has a different copper-to-carbonate ratio and is not an interchangeable name for the green compound covered here.

Physical appearance

Basic copper carbonate is generally a green, odorless solid supplied as a powder.
Differences in precipitation, drying, milling, and particle aggregation can change its shade and apparent density.
A specification for a particular application may therefore describe physical characteristics in addition to chemical identity and copper content.
The theoretical formula corresponds to a copper content of approximately 57.5% by mass.
An actual commercial powder may have a lower measured copper percentage because of moisture, residual process materials, or other constituents.
Copper content stated on a product specification should be read as an assay for that grade rather than assumed from its name.

Preparation and particle characteristics

A common preparation route reacts a dissolved copper(II) salt with a carbonate or bicarbonate source to precipitate copper carbonate hydroxide.
Reaction conditions influence how the solid forms and can affect surface area and density.
Washing and drying then help control residual soluble salts and the physical form of the finished powder. 

Copper carbonate particle size matters when the powder must disperse evenly or react at a predictable rate.
Fine particles present more accessible surface to liquids but can also create more airborne dust during handling.
Agglomerates may behave differently from individual particles, particularly in ceramic slurries and other suspended systems.

Solubility and chemical behavior

Copper carbonate is poorly soluble in water and ordinarily forms a suspension rather than a clear solution.
Acids dissolve it by reacting with the carbonate and hydroxide components, yielding dissolved copper species and releasing carbon dioxide.
Its behavior in a complex liquid can differ from that in plain water when acidity or copper-binding ingredients are present.
Copper carbonate can interact with ammonia-containing media through formation of dissolved copper complexes.
The resulting liquid is chemically different from a simple water dispersion of the original powder.
For this reason, solution color or clarity does not by itself establish that unchanged copper carbonate remains suspended.

Thermal behavior

Copper carbonate decomposes on heating to form copper(II) oxide, carbon dioxide, and water.
Its thermal behavior is better described as decomposition than by assigning a conventional boiling point to the intact compound.
The release of gases is relevant both to oxide manufacture and to defects that can arise during ceramic firing.

Storage and formulation stability

Copper carbonate retains its intended composition best when protected from contamination and unnecessary contact with reactive materials.
Strong acids consume the basic carbonate, while heating causes the chemical transformation described above.
In a liquid formulation, sedimentation and changes in the surrounding chemistry may be as important as the stability of the dry compound.

PROPERTIES

Chemical nature: Basic copper(II) carbonate hydroxide
Appearance: Green powder
Odor: Odorless
Molecular formula: Cu₂CO₃(OH)₂
Molecular weight: 221.12 g/mol
Theoretical copper content: Approximately 57.5% by mass
Water solubility: Poorly soluble
Acid reactivity: Dissolves with release of carbon dioxide
Ammonia-containing media: Can form dissolved copper complexes
Thermal behavior: Decomposes to copper(II) oxide, carbon dioxide, and water
Melting point: No conventional melting point for the intact compound; it decomposes on heating
Boiling point: Not applicable to the intact compound
Flash point: Not applicable to the inorganic solid
Density: Approximately 4.0 g/cm³ for a reported basic copper carbonate grade; bulk density varies with powder form
Dust hazard: Airborne powder may irritate the respiratory tract and is harmful if inhaled
Eye hazard: Causes serious eye irritation
Environmental hazard: Hazardous to aquatic life, with long-lasting effects. 

FIRST AID

Inhalation:

Move the person to fresh air and keep them comfortable for breathing.
Seek prompt medical advice if they feel unwell, cough persistently, or have breathing difficulty.

Skin contact:

Remove contaminated clothing and wash the affected skin thoroughly with water.
Obtain medical advice if irritation develops or persists.

Eye contact:

Rinse cautiously with water for several minutes, removing contact lenses if present and easy to do.
Continue rinsing and obtain medical attention if irritation persists.

Ingestion:

Rinse the mouth and do not induce vomiting.
Contact a poison center or physician promptly, particularly if a significant amount was swallowed or symptoms occur.

Note to physicians:

Treat according to the exposure and clinical findings; no specific antidote is identified for routine exposure to this compound. 

HANDLING AND STORAGE

Handling:

Avoid breathing dust and prevent the powder from contacting the eyes.
Wear suitable gloves, protective clothing, and eye protection when transferring or weighing the material.

Ventilation:

Provide effective local extraction where powder is poured, mixed, or otherwise dispersed.
Operations that heat or decompose the material require ventilation suited to the process emissions.

Storage:

Keep containers tightly closed in a dry, well-ventilated place.
Store away from strong acids and strong oxidizing agents. 

Spill and leak procedures:

Prevent the powder from entering drains, surface water, or soil.
Collect spilled material carefully into suitable closed containers while minimizing dust generation.
Dispose of contaminated material according to the applicable requirements.

Handling precautions:

Do not eat, drink, or smoke while handling the powder, and wash exposed skin afterward.
Avoid cleaning methods that disperse dust into the air.
Assess the hazards of any finished mixture separately because its other ingredients and physical form can change the required controls.