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Copper oxychloride is an inorganic compound with the chemical formula Cu₂(OH)₃Cl, belonging to the class of copper(II) salts, and appears as a light green to bluish-green fine crystalline powder that is practically insoluble in water but can be suspended to form a stable suspension.
Copper oxychloride is widely recognized for its application as a fungicide and bactericide in agriculture, where it forms a protective barrier on plant surfaces and interferes with the enzymatic processes of pathogenic microorganisms, thereby preventing spore germination and fungal growth.
The global market for copper oxychloride is driven primarily by its widespread use as a fungicide and bactericide in the agriculture industry, particularly for high-value crops like citrus fruits, grapes, tomatoes, avocados, and coffee, and is supported by trends in organic farming and sustainable agriculture.
CAS Number: 1332-65-6
EC Number: 215-572-9
Molecular Formula: Cu₂(OH)₃Cl
Molar Mass: 213.56 g/mol
Synonyms: Basic copper chloride, Cl2Cu.3CuH2O2, copper oxychloride, AldrichCPR, DTXSID6034348, 8310AF, 1332-40-7 , 1332-65-6 , 215-572-9 , basic copper chloride, Chlorure hydroxyde de cuivre(2+) (1:3:2) , copper chloride oxide hydrate, copper oxychloride , Copper(2+) chloride hydroxide (2:1:3), dicopper(II) chloride trihydroxide, Kupfer(2+)chloridhydroxid (2:1:3) , Kupfer(2+)chloridhydroxid(2:1:3), tribasic copper chloride, 8012-69-9 [RN], Agrizan, Areeco, Areecop, ATACAMITE, Blitox, Blitox 50, Blue Copper, Blue Copper 50, Bordeaux A, Bordeaux Z, ChemNut 50, Chemocin, Chloride , Cobox, Cobox Blue, Cobrex, Colloidox, Copen , Copper chloride hydroxide, Copper chloride oxide, hydrate, Copper chloride oxide, hydrate (9CI), Copper chloride, basic, Copper chloride, mixed with copper oxide, hydrate, Copper chloroxide, Copper OC fungicide, Copper oxychloride, Copper oxychloride sulfate, Copper(II) chloride hydroxide (8CI), Copper(II) chloride oxide hydrate (9CI), Coppercide, Copperthom, Coppesan, Coppesan Blue, Coprantol, Coprex, Coprosan Blue, Cupral 45, Cupramer, Cuprargos, Cuprasol, Cupravit, Cupravit Green, Cupravit-Forte, Cupric oxide chloride, Cupricol, Cupritox, Cuprokylt, Cuprokylt L, Cuprosan Blue, Cuprovit, Cuprox, Cuproxol, Demildex, dicopper, Dicopper chloride trihydroxide , DICOPPER(2+) ION CHLORIDE TRIHYDROXIDE, dicopper;chloride;trihydroxide, dicupric chloride trihydroxide, ER , Faligruen, Funguran, Fyco, Fycol 8, Fycop, Fycop 40A, Fytolan, H 200A, Hokko Cupra Super, Kauritil, Kupferoxychlorid , Kupferoxychlorid , Kupricol, Kuprikol, MACC, Maccppper, Microco, Microcop, Miedzian, Miedzian 50, Oxicob, Oxivor, Oxychlorue de cuivre, Oxychlorue de cuivre , Oxychlorure de cuivre , Oxychlorure de cuivre , Oxyclor, Oxycur, Parryco, Parrycop, pBlitox, pCopper oxychloride, Peprosan, pFycop 40A, pMiedzian, Pol-kupritox, pPeprosan, Reco, Recop, Tamraghol, Tetracopper hexahydroxide sulfate, tetracupric hexahydroxide sulfate, Tricop 50, trihydroxide, Turbair Copper Fungicide, UNII:76712031PG, UNII-76712031PG, UNII-IF628703RE, Viricuivre, Vitigran, Vitigran Blue, Agrizan, Areecop, Blitox, Blitox 50, Blue Copper, Blue Copper 50, Bordeaux A, Bordeaux Z, ChemNut 50, Chemocin, Cobox, Cobox Blue, Cobrex, Colloidox, Copen, Copper OC fungicide, Copper chloride oxide, hydrate, Copper chloride, basic, Copper chloroxide, Copper oxychloride [ISO], Copper(II) chloride hydroxide (8CI), Copper(II) chloride oxide hydrate (9CI), Coppercide, Copperthom, Coppesan, Coppesan Blue, Coprantol, Coprex, Coprosan Blue, Cozib 62, Cupral 45, Cupramer, Cuprargos, Cuprasol, Cupravit, Cupravit Green, Cupravit-Forte, Cupric oxide chloride, Cupricol, Cupritox, Cuprokylt, Cuprokylt L, Cuprosan Blue, Cuprovit, Cuprox, Cuproxol, Demildex, Dicopper chloride trihydroxide, Faligruen, Funguran, Fycol 8, Fycop, Fycop 40A , Fytolan, H 200A, Hokko Cupra Super, KT 35, Kauritil, Kupferoxychlorid, Kupricol, Kuprikol, Maccppper, Microcop, Miedzian, Miedzian 50, Ob 21, Oxicob, Oxivor, Oxychlorue de cuivre , Oxychlorure de cuivre, Oxyclor, Oxycur, Parrycop, Peprosan, Recop, Tamraghol, Tricop 50, Turbair Copper Fungicide, Viricuivre, Vitigran, Vitigran Blue, Copper (II) oxychloride, Miedzian, Oxyclor, Parrycop, Peprosan, Tamraghol, Viricuivre, Vitigran, Cobrex, Coprex, Cuprox, Oxicob, Oxivor, Oxycur, Cobox, Copen, Fycop, Recop, Coppesan Blue, Coprosan Blue, Cupravit Green, Cupravit-Forte, Cuprosan Blue, Vitigran Blue, Cuprokylt L, Bordeaux A, Bordeaux Z, Cobox Blue, Copper chloroxide, Hokko Cupra Super, Blue Copper 50, Fycol 8, Copper OC fungicide, Blitox 50, ChemNut 50, Cupral 45, Tricop 50, Cupric oxide chloride, Cozib 62, Fycop 40A, Caswell No. 249, Copper chloride, basic, Kupferoxychlorid, Turbair Copper Fungicide, Kupferoxychlorid [German], Copper oxychloride [ISO], Copper(II) chloride hydroxide, Ob 21, Oxychlorue de cuivre, Oxychlorue de cuivre [French], Oxychlorure de cuivre, Copper(II) chloride oxide hydrate, KT 35, Oxychlorure de cuivre [ISO-French], H 200A, EPA Pesticide Chemical Code 023501, Oxychlorure de cuivre (ISO-French), Perecol, CupravitForte, Oxy COC, CASWELL No 072, DTXCID4014475, Copper chloride oxide, hydrate (9CI), Copper(II) chloride hydroxide (8CI), dicopper(2+) ion chloride trihydroxide, Copper(II) chloride oxide hydrate (9CI), 215-572-9, 603-724-0, 1332-40-7, 1332-65-6, aviocaffaro, aviocaffaro pf, basic copper chloride (cu2cl(oh)3), basic cupric oxychloride, caswell no. 072, chempar, cop tox, copper chloride (cu2(oh)3cl), copper chloride hydroxide, copper chloride hydroxide (cu2(oh)3cl), copper chloride oxide, hydrate, copper hydroxide chloride (cu2(oh)3cl), copper oxychloride, copper(ii) oxychloride, criscobre, cudrox, cuidrox, cupracol, cupric hydroxide chloride (cu(oh)1,5cl0.5), cuprocaffaro, cuprosana, cuprovinol, cuproxol, devicopper, dicopper chloride trihydroxide, dicopper(ii) chloride trihydroxide, dtxsid6034475, ec 215-572-9, einecs 215-572-9, epa pesticide chemical code 008001, fernacot, hsdb 5815, kilex, micronutrients tbcc, natural atacamite, natural paratacamite (gamma) and (beta), neoram, neoram blu, pasta caffaro, pere-col, rhodiacuivre, dicopper;dichloride;trihydroxide, dicopper(II) dichloride trihydroxide, Pol-kupritox, Miedzian 50, CPOSXJRGXIJOHG-UHFFFAOYSA-I, AKOS040744553, NS00078652
Copper oxychloride is the compound with chemical formula Cu2(OH)3Cl.
Copper oxychloride is often referred to as tribasic copper chloride (TBCC), copper trihydroxyl chloride or copper hydroxychloride.
Copper oxychloride is encountered as the minerals atacamite, paratacamite, and botallackite.
Similar materials are assigned to green solids formed upon corrosion of various copper objects.
Copper oxychloride used in agriculture.
Copper oxychloride is an inorganic compound with the chemical formula Cu₂(OH)₃Cl, belonging to the class of copper(II) salts.
Copper oxychloride appears as a light green to bluish-green fine crystalline powder that is practically insoluble in water but can be suspended in water to form a stable suspension.
Copper oxychloride is widely recognized for its application as a fungicide and bactericide in agriculture, where it is used to protect crops such as tomatoes, potatoes, citrus fruits, coffee, grapes, and vegetables against fungal diseases like downy mildew, leaf spots, and blights.
Copper oxychloride operates primarily through contact action, forming a protective barrier on plant surfaces and interfering with the enzymatic processes of pathogenic microorganisms, thereby preventing spore germination and fungal growth.
In addition to its agricultural significance, copper oxychloride also finds limited use as a pigment and in the preparation of other copper compounds.
Industrially, Copper oxychloride can be synthesized by the controlled reaction of copper(II) chloride with copper(II) hydroxide or by the hydrolysis of copper(II) chloride solutions.
Its effectiveness, stability, and broad-spectrum activity have made copper oxychloride a key component of many crop protection programs, particularly in regions where resistance management and organic certification are priorities.
Despite its usefulness, care must be taken in handling and applying copper oxychloride, as excessive accumulation in soil can potentially lead to environmental toxicity, particularly affecting aquatic organisms and beneficial soil microorganisms.
Regulatory frameworks in many countries specify maximum allowable limits for copper-based products to minimize long-term environmental impact while maintaining their agricultural benefits.
Copper oxychloride is a basic copper chloride compound that exists as a light green to blue-green crystalline powder, widely used for Copper oxychloride's antimicrobial properties.
Structurally, Copper oxychloride is a layered hydroxide salt where copper atoms are coordinated with hydroxide and chloride ions, giving it stability and low water solubility.
Copper oxychloride was historically developed as an improvement over earlier copper-based fungicides such as Bordeaux mixture, providing better adherence to plant surfaces and longer protection.
Copper oxychloride functions as a contact fungicide and bactericide, remaining on the surface of plant tissues and releasing copper ions slowly upon contact with moisture.
These copper ions denature proteins and enzymes within fungal and bacterial cells, disrupting metabolic pathways and preventing infection spread.
Copper oxychloride is extensively applied in agriculture to protect a wide variety of crops including citrus, coffee, grapes, tomatoes, potatoes, and avocados from fungal pathogens like Phytophthora, Alternaria, Plasmopara, and bacterial infections such as bacterial spot and canker.
Copper oxychloride is valued for its broad-spectrum efficacy, persistence under rainy conditions, and suitability for organic farming systems, provided it is used according to regulations that limit total copper accumulation in soils.
Industrial production of copper oxychloride typically involves the controlled hydrolysis of copper(II) chloride or the direct combination of copper(II) sulfate with a chloride source under alkaline conditions.
This process yields a fine, easily suspendable powder suitable for formulation into wettable powders, dusts, and suspension concentrates.
Formulated products often combine copper oxychloride with other fungicides or adjuvants to enhance spreadability, adhesion, and rainfastness.
While effective, copper oxychloride usage must be managed carefully due to environmental concerns.
Excessive copper accumulation from repeated applications can lead to soil toxicity, harming beneficial microorganisms and earthworms, and runoff into aquatic systems can be toxic to fish and aquatic invertebrates.
For this reason, many regulatory agencies, such as the European Food Safety Authority (EFSA) and the United States Environmental Protection Agency (EPA), monitor and limit copper usage rates.
Aside from agriculture, copper oxychloride is occasionally used as a pigment in ceramics and glassmaking, where it imparts greenish-blue hues.
Copper oxychloride is also a precursor for other copper-based chemical products used in catalysts and industrial applications.
Handling requires precautions including the use of personal protective equipment to avoid inhalation of dust or prolonged skin contact, given Copper oxychloride's classification as an irritant.
Overall, copper oxychloride remains a vital and versatile tool in modern crop protection, particularly valued for its preventive action, broad pathogen spectrum, and resilience under varying environmental conditions.
Research continues into optimizing Copper oxychloride's formulations and application methods to balance agricultural productivity with environmental sustainability.
Market Overview of Copper Oxychloride:
The global market for copper oxychloride is driven primarily by its widespread use as a fungicide and bactericide in the agriculture industry, particularly for high-value crops like citrus fruits, grapes, tomatoes, avocados, and coffee.
Demand is especially strong in regions with humid or tropical climates where fungal diseases are prevalent, including Asia-Pacific, Latin America, and parts of Europe.
The increasing global emphasis on organic farming and sustainable agriculture has further supported copper oxychloride usage, as it is allowed in many organic certification systems within regulated application limits.
Additionally, Copper oxychloride's role as a low-cost, broad-spectrum protective agent makes it attractive to farmers seeking affordable and reliable disease management options.
However, regulatory scrutiny over copper accumulation in soils has led to a gradual shift toward optimized formulations with lower copper content or combined products.
Leading manufacturers are focusing on innovations to improve product performance, rainfastness, and environmental safety.
The market is projected to grow steadily, supported by trends in increasing food demand, crop protection needs, and climate change-driven disease pressures, although growth is moderated by regulatory pressures and competition from newer synthetic fungicides.
Expansion into biological and integrated pest management (IPM) programs also presents opportunities for copper oxychloride in combination with biocontrol agents.
Uses of Copper Oxychloride:
Copper oxychloride is widely used primarily as a fungicide and bactericide in agriculture and horticulture.
Copper oxychloride is applied to protect crops such as citrus fruits, grapes, tomatoes, potatoes, avocados, coffee, and a variety of vegetables from a broad range of fungal diseases, including downy mildew, leaf spot, blights, anthracnose, and bacterial infections like bacterial canker and bacterial spot.
Copper oxychloride acts by forming a protective barrier on the surface of plants, preventing fungal spores and bacterial cells from germinating and establishing infection.
Copper oxychloride's strong adherence to plant surfaces makes it particularly valuable in areas with frequent rainfall.
Copper oxychloride is commonly used in both conventional and organic farming systems due to its natural mineral origin and its acceptance under many organic certification standards (within certain copper application limits).
Beyond its agricultural applications, copper oxychloride also serves as a pigment in the production of ceramics and glasses, imparting distinctive green to bluish-green colors.
Additionally, Copper oxychloride acts as an intermediate chemical in the synthesis of other copper-based compounds used in catalysis and industrial processes.
In some cases, Copper oxychloride has been investigated for potential use in wood preservation due to its antimicrobial properties.
Although Copper oxychloride's principal role remains in plant disease management, the versatility and broad-spectrum antimicrobial activity of copper oxychloride make it an important material across several sectors.
Agriculture and Horticulture:
Copper oxychloride is used as a fungicide and bactericide to protect crops like tomatoes, potatoes, citrus fruits, grapes, coffee, and avocados.
Controls diseases such as downy mildew, leaf spot, early and late blight, anthracnose, bacterial canker, and bacterial spot.
Organic Farming:
Accepted in organic agriculture (within regulated copper usage limits) as a natural mineral fungicide.
Forestry and Wood Preservation:
Copper oxychloride is sometimes used for wood treatment due to its antimicrobial properties to prevent fungal decay.
Ceramics and Glass Industry:
Copper oxychloride is used as a pigment to produce green to bluish-green colors in ceramics, pottery, and glassmaking.
Chemical Industry:
Copper oxychloride serves as a precursor for synthesizing other copper-based chemical compounds and industrial catalysts.
Environmental Management:
Occasionally explored for use in algae control in aquatic systems (limited and regulated due to toxicity risks).
Applications of Copper Oxychloride:
As an agriculture fungicide:
Fine Copper oxychloride has been used as a fungicidal spray on tea, orange, grape, rubber, coffee, cardamom, and cotton etc., and as an aerial spray on rubber for control of phytophthora attack on leaves.
As a pigment:
Copper oxychloride has been used as a pigment and as a colorant for glass and ceramics.
Copper oxychloride was widely used as a coloring agent in wall painting, manuscript illumination, and other paintings by ancient people.
Copper oxychloride was also used in cosmetics by ancient Egyptians.
In pyrotechnics:
Copper oxychloride has been used as a blue/green coloring agents in pyrotechnics.
As a catalyst:
Copper oxychloride has been used in the preparation of catalysts and as a catalyst in organic synthesis for chlorination and/or oxidation.
Copper oxychloride has been shown to be a catalyst in the chlorination of ethylene.
Atacamite and paratacamite crystal forms of Copper oxychloride have been found to be active species in supported CuCl2 catalyst systems for the oxidative carbonylation of methanol to dimethyl carbonate.
A number of supported Copper oxychloride catalysts have also been prepared and studied in such conversion.
Dimethyl carbonate is an environmentally benign chemical product and unique intermediate with versatile chemical reactivity.
Copper oxychloride has been identified as a new catalytically active material for the partial oxidation of n-butane to maleic anhydride.
A mixture of ultrafine powder CuO/Copper oxychloride has been shown to be good in photo-catalytic decolorization of dyes, such as amido black, and indigo carmine.
As a feed supplement:
Copper is one of the most critically important of the trace minerals that are essential elements in numerous enzymes that support metabolic functions in most organisms.
Since the early 1900s, copper has routinely been added to animal feedstuffs to support good health and normal development.
Starting in the 1950s, there was increasing focus on the issue of bioavailability of trace mineral supplements which led to copper sulfate pentahydrate becoming the predominant source.
Because of Copper oxychloride's high water solubility, and thus hygroscopicity, CuSO4 leads to destructive reactions in feed mixtures.
These are notoriously destructive in hot, humid climates.
Recognition that basic copper chloride would reduce feed stability problems led to issuance of patents on the use of Copper oxychloride as a nutritional source.
Subsequently, animal feeding studies revealed that the alpha crystal form of basic copper chloride has a rate of chemical reactivity that is well matched to biological processes.
The strength of the bonds holding copper in the alpha crystal polymorphs could prevent undesirable, anti-nutritive interactions with other feed ingredients while delivering controlled amounts of copper throughout the active zones in the digestive tract of an animal.
Success in producing alpha basic copper chloride on a large scale allowed for the widespread application of basic copper chloride in the feed thereby supplying the copper requirements of all major livestock groups.
This form of Copper oxychloride has proven to be particularly suitable as a commercial feed supplement for use in livestock and aquaculture due to its inherent chemical and physical characteristics.
Compared to copper sulfate, the alpha crystal form of basic copper chloride provides many benefits including improved feed stability, less oxidative destruction of vitamins and other essential feed ingredients; superior blending in feed mixtures, and reduced handing costs.
Copper oxychloride has been widely used in feed formulations for most species, including chickens, turkeys, pigs, beef and dairy cattle, horses, pets, aquaculture and exotic zoo animals.
Benefits of Copper Oxychloride:
Broad-Spectrum Disease Control:
Effective against a wide range of fungal and bacterial plant pathogens, providing comprehensive crop protection.
Preventive Action:
Copper oxychloride acts as a protective barrier on plant surfaces, preventing the establishment and spread of infections before they occur.
Good Adherence to Plants:
Forms a persistent layer that adheres well even under rainy conditions, reducing the need for frequent reapplications.
Low Risk of Resistance Development:
Copper compounds have a multi-target mode of action, making it difficult for pathogens to develop resistance compared to single-target synthetic fungicides.
Compatibility with Organic Farming:
Accepted under many organic certification standards, allowing organic growers to effectively manage diseases using a naturally derived mineral.
Versatile Formulations:
Copper oxychloride can be formulated as wettable powders, suspension concentrates, or dusts, allowing flexibility in application methods.
Cost-Effective:
Copper oxychloride offers a relatively economical option for disease management compared to some modern synthetic fungicides.
Stability and Shelf Life:
Copper oxychloride products are chemically stable and have a long shelf life, ensuring reliability over storage periods.
Dual Antifungal and Antibacterial Properties:
Copper oxychloride provides both antifungal and antibacterial protection in a single application, simplifying treatment schedules.
Environmental Persistence (When Managed Properly):
Copper oxychloride remains effective for longer periods in the field without immediate degradation, enhancing protection over time (though accumulation must be managed responsibly).
Features of Copper Oxychloride:
Chemical Composition:
Basic copper chloride with the chemical formula Copper oxychloride, containing both hydroxide and chloride ions coordinated to copper.
Physical Appearance:
Fine light green to bluish-green powder; practically insoluble in water but forms stable suspensions.
Mode of Action:
Copper oxychloride acts as a contact fungicide and bactericide, releasing copper ions that disrupt microbial enzyme systems and protein functions.
Persistence:
Forms a durable protective layer on plant surfaces, offering prolonged disease protection especially in rainy or humid environments.
Formulation Flexibility:
Available in various formulations such as wettable powders (WP), suspension concentrates (SC), and dusts, suitable for different application methods (spraying, dusting).
Low Water Solubility:
Ensures slow release of copper ions, reducing immediate environmental leaching and providing sustained action.
Compatibility:
Compatible with many other pesticides and agricultural adjuvants, allowing tank-mix applications for integrated disease management.
Organic Farming Approval:
Approved for use in many organic farming systems under certain copper application limits, due to Copper oxychloride's natural mineral origin.
Stability:
Exhibits good chemical and physical stability during storage, maintaining effectiveness over long periods.
Broad Crop Range:
Suitable for use on a wide variety of crops including fruits, vegetables, coffee, cereals, and ornamental plants.
Production of Copper Oxychloride:
Copper oxychloride is industrially produced through controlled chemical reactions involving copper salts and alkaline agents.
One common method is the hydrolysis of copper(II) chloride (CuCl₂) in water, where copper oxychloride precipitates while hydrochloric acid is released as a by-product.
Another widely used process involves reacting copper(II) sulfate (CuSO₄) with a chloride source such as sodium chloride (NaCl) in the presence of an alkaline compound like calcium hydroxide (Ca(OH)₂), leading to the formation of copper oxychloride along with by-products like calcium sulfate.
After precipitation, Copper oxychloride is filtered, washed to remove soluble impurities, dried, and finely ground to achieve the desired particle size for agricultural formulations.
These steps must be carefully controlled to ensure high purity and optimal physical properties, such as good suspension behavior and minimal dust formation.
Industrial production is usually performed in closed systems to protect both workers and the environment, as well as to comply with regulatory standards.
Final formulations such as wettable powders and suspension concentrates are prepared by adding surfactants and dispersing agents, making Copper oxychloride easier to apply on crops.
Overall, the production of copper oxychloride is a precise chemical process that balances efficiency, product quality, and environmental responsibility.
Industrial Production:
Air oxidation of copper(I) chloride in brine solution:
Large scale industrial production of basic copper chloride was devoted to making either a fungicide for crop protection or an intermediate in the manufacture of other copper compounds.
In neither of those applications was the polymorphic nature of Copper oxychloride, or the size of individual particles of particular importance, so the manufacturing processes were simple precipitation schemes.
Copper oxychloride can be prepared by air oxidation of CuCl in brine solution.
The CuCl solution is usually made by the reduction of CuCl2 solutions over copper metal.
A CuCl2 solution with concentrated brine is contacted with copper metal until the Cu(II) is completely reduced.
The resulting CuCl is then heated to 60–90 °C (140–194 °F) and aerated to effect the oxidation and hydrolysis.
The oxidation reaction can be performed with or without the copper metal.
The precipitated product is separated and the mother liquor containing CuCl2 and NaCl, is recycled back to the process:
CuCl2 + Cu + 2 NaCl → 2 NaCuCl2
12 NaCuCl2 + 3 O2 + 2 H2O → 4 Cu2(OH)3Cl + 4 CuCl2 + 12 NaCl
Copper oxychloride from this process is of fine particle with size of 1 ~ 5 μm and is usable as an agricultural fungicide.
Astable, free-flowing, non-dusty green powder with typical particle size of 30 ~ 100 microns has been used in preparation of uniform animal feed mixtures.
There are two types of spent etching solutions from printed circuit board manufacturing operations: an acidic cupric chloride solution (CuCl2/HCl), and an alkaline tetraamminedichloridocopper(II) solution (Cu(NH3)4Cl2).
Tribasic copper chloride is generated by neutralization of either one of these two solutions (acidic or alkaline pathway), or by combination of these two solutions, a self-neutralization reaction.
In the acidic pathway, the cupric chloride solution can be neutralized with caustic soda, or ammonia, lime, or other base.
In the alkaline pathway, cuprammine chloride solution can be neutralized with HCl or other available acidic solutions:
2 [Cu(NH3)4Cl2] + 5 HCl + 3 H2O → Cu2(OH)3Cl + 8 [NH4]Cl
More efficiently, the two spent etching solutions are combined under mild acidic conditions, one neutralizing the other, to produce higher yield of basic copper chloride:
3 [Cu(NH3)4Cl2] + 5 CuCl2 + 12 H2O → 4 Cu2(OH)3Cl + 12 [NH4]Cl
Seeding is introduced during crystallization.
The production is operated continuously under well-defined conditions (pH, feeding rate, concentrations, temperature, etc.).
Product with good particle size is produced and can be easily separated from background salt and other impurities in the mother liquor.
After simple rinse with water and drying, pure, free-flowing, non-dusty green crystalline solid with typical particle size of 30 ~ 100 micron is obtained.
Copper oxychloride from this process is predominantly atacamite and paratacamite, the stable crystal forms of basic copper chloride – and is called alpha basic copper chloride for simplicity.
Careful control of process conditions to favor the alpha polymorphs results in a product that remains free flowing over extended storage times, thus avoiding caking as occurs with both copper sulfate and the botallackite crystal form - also called beta basic copper chloride.
This process is used to manufacture thousands of tons of tribasic copper chloride every year, and has been the predominant route of commercial production since it was introduced by Steward in 1994.
Synthesis of Copper Oxychloride:
Copper oxychloride is synthesized by controlled chemical reactions involving copper salts in aqueous environments under alkaline conditions.
One common synthesis route involves the partial hydrolysis of copper(II) chloride (CuCl₂) with water at moderate temperatures, leading to the formation of copper oxychloride and hydrochloric acid as a by-product.
The reaction proceeds as follows:
2CuCl2+3H2O⟶Cu2(OH)3Cl+3HCl
Another method uses copper(II) sulfate (CuSO₄), which reacts with a chloride source such as sodium chloride (NaCl) or calcium chloride (CaCl₂) in the presence of an alkaline agent like calcium hydroxide (Ca(OH)₂).
This pathway results in copper oxychloride along with secondary products like calcium sulfate.
The precipitation reaction must be carefully controlled to ensure that copper oxychloride forms without significant contamination from copper hydroxide or copper carbonate.
Once precipitated, the solid is filtered, washed to remove soluble impurities, dried, and finely ground to produce a uniform, water-suspendable powder.
Control of pH, temperature, and reaction stoichiometry is critical to achieve the optimal particle size, crystallinity, and copper content required for agricultural applications.
The synthesized copper oxychloride is then formulated into fungicide products such as wettable powders, dusts, or suspension concentrates, optimized for good field performance and stability.
Occurence of Copper Oxychloride:
Copper oxychloride does not occur widely as a major natural mineral in the environment but is found in certain rare mineral forms and as a product of secondary mineralization processes involving copper ores.
One of the naturally occurring minerals corresponding to copper oxychloride is atacamite, a bright green mineral composed primarily of Copper oxychloride, which forms under arid, saline, and oxidizing conditions where copper deposits are exposed to chloride-rich environments.
Atacamite and Copper oxychloride's polymorphs, such as botallackite and paratacamite, are often found in copper mining areas where copper sulfide ores like chalcopyrite and bornite have weathered and reacted with chloride-containing groundwater or sea spray.
While these natural occurrences are geologically significant, industrially used copper oxychloride is not mined but is instead synthesized through chemical processes to ensure purity, consistency, and suitability for agricultural use.
Small amounts of copper oxychloride-like compounds can also form on the surfaces of weathered copper artifacts, particularly those buried in chloride-containing soils, contributing to the green patina often seen on archaeological copper objects.
However, for practical purposes, the copper oxychloride used commercially is a manufactured compound rather than a naturally extracted material.
Natural Occurrence:
Copper oxychloride occurs as natural minerals in four polymorphic crystal forms: atacamite, paratacamite, clinoatacamite, and botallackite.
Atacamite is orthorhombic, paratacamite is rhombohedral, and the other two polymorphs are monoclinic.
Atacamite and paratacamite are common secondary minerals in areas of copper mineralization and frequently form as corrosion products of Cu-bearing metals.
The most common Copper oxychloride polymorph is atacamite.
Copper oxychloride is an oxidation product of other copper minerals, especially under arid, saline conditions.
Copper oxychloride was found in fumarolic deposits, and a weathering product of sulfides in subsea black smoker deposits.
Copper oxychloride was named for the Atacama Desert in Chile.
Copper oxychloride's color varies from blackish to emerald green.
Copper oxychloride is the sugar-like coating of dark green glistening crystals found on many bronze objects from Egypt and Mesopotamia.
Copper oxychloride has also been found in living systems such as the jaws of the marine bloodworm Glycera dibranchiata.
The stability of atacamite is evidenced by Copper oxychloride's ability to endure dynamic regimes in its natural geologic environment.
Paratacamite is another Copper oxychloride polymorph that was named for the Atacama Desert in Chile.
Copper oxychloride has been identified in the powdery light-green corrosion product that forms on a copper or bronze surface – at times in corrosion pustules.
Copper oxychloride can be distinguished from atacamite by the rhombohedral shape of its crystals.
Botallackite is the least stable of the four Copper oxychloride polymorphs.
Copper oxychloride is pale bluish-green in color.
This rare mineral was first found, and later identified, in the Botallack Mine in Cornwall, England.
Copper oxychloride is also a rare corrosion product on archaeological finds.
For instance, Copper oxychloride was identified on an Egyptian statue of Bastet.
The fourth polymorph of Copper oxychloride family is clinoatacamite.
Copper oxychloride was found and identified around in Chuquicamata, Chile in 1996.
Copper oxychloride was named in allusion to its monoclinic morphology and relationship to atacamite.
Copper oxychloride is pale green but has monoclinic crystals.
Clinoatacamite can be easily confused with the closely related paratacamite.
Copper oxychloride is believed that clinoatacamite should replace most previously reported occurrences of paratacamite in the conservation literature.
Structure of naturally occurring forms:
Atacamite is orthorhombic, space group Pnma, with two crystallographically independent Copper and Oxygen atoms of hydroxyl groups in the asymmetric unit.
Both Cu atoms display characteristically Jahn-Teller distorted octahedral (4+2) coordination geometry: each Cu is bonded to four nearest OH groups with Cu-OH distance of 2.01 Å; in addition, one of Cu atoms is bonded to two Cl atoms (at 2.76 Å) to form a [Cu(OH)4Cl2] octahedron, and the other Cu atom is bonded to one Cl atom (at 2.75 Å) and a distant OH group (at 2.36 Å) to form a [Cu(OH)5Cl] octahedron.
The two different types of octahedron are edge-linked to form a three-dimensional framework with the [Cu(OH)5Cl] octahedron cross-linking the [Cu(OH)4Cl2] octahedron layers parallel to (110).
Botallackite crystallizes in monoclinic with space group P21/m.
Like in atacamite, there are two different types of Cu coordination geometries:
Jahn-Teller distorted octahedral [Cu(OH)4Cl2] and [Cu(OH)5Cl].
But these octahedra assemble in different ways.
Each octahedron shares six edges with surrounding octahedra, forming a two-dimensional sheet-type structure parallel to (100).
The adjacent sheets are held together by hydrogen bonding between the hydroxyl oxygen atoms of one sheet and the opposing chlorine atoms in the other sheets.
The resulting weak bonding between the sheets accounts for the perfect (100) cleavage and the typical platy habit of botallackite.
Paratacamite is rhombohedral, space group R3.
Copper oxychloride has a well-developed substructure with a’=a/2, c’=c, apparent space group R3m.
There are four crystallographically independent Cu atoms in the asymmetric unit.
The Cu atoms display three different types of octahedral coordination geometries.
Three quarters of the Cu atoms are coordinated to four near OH groups and two distant Cl atoms, giving the expected (4+2) configuration [Cu(OH)4Cl2].
Three sixteenths of the Cu atoms are bonded to two near OH groups at 1.93 Å and four stretched OH groups at 2.20 Å to form an axially compressed (2+4) octahedral [Cu(OH)6], and the remaining one sixteenth of the Cu atoms are bonded to six equivalent OH groups at 2.12 Å to form a regular octahedral [Cu(OH)6].
The Jahn-Teller distorted [Cu(OH)4Cl2] octahedra share the edges and form partially occupied layers parallel to (001), and the compressed and regular [Cu(OH)6] octahedra cross-link the adjacent [Cu(OH)4Cl2] octahedral layers to form a three-dimensional framework.
The existence of the regular octahedral [Cu(OH)6] is unusual, and Copper oxychloride has been shown that partial substitution of Zn or Ni for Copper at this special site (3b) is necessary to stabilize paratacamite structure at ambient temperature.
Due to the high symmetry of the special position, only about 2 wt% Zn is necessary to stabilize the rhombohedral structure.
In fact, most of paratacamite crystals studied contain significant amounts of Zn or Ni (> 2 wt%).
Clinoatacamite is monoclinic, space group P21/m.
The structure is very close to that of paratacamite.
But the [Cu(OH)6] octahedron is Jahn-Teller distorted.
The Jahn-Teller distorted [Cu(OH)4Cl2] octahedra share the edges to form partially occupied layers parallel to (101).
This layer is topologically the same as that in mica.
Adjacent layers of octahedra are offset, such that vacant sites in one sheet align with occupied sites in the neighboring sheet.
The [Cu(OH)6] octahedra link the layers to form a 3-dimensional network.
Thermodynamic data based on the free energy of formation indicates that the order of stability of these polymorphs is clinoatacamite>atacamite> botallackite.
Spectroscopic studies show that the strength of hydrogen bonding in these polymorphs is in the order paratacamite >atacamite> botallackite.
Studies on the formation of basic copper chloride indicate botallackite is a key intermediate and crystallizes first under most conditions; subsequent recrystallization of botallackite to atacamite or paratacamite depends on the nature of reaction medium.
History of Copper Oxychloride:
The history of copper oxychloride is closely tied to the long-standing use of copper compounds in agriculture for disease control.
Although copper itself has been used since ancient times as a medicinal and antimicrobial agent, copper oxychloride as a distinct chemical product emerged much later, during the development of modern agricultural chemistry in the early 20th century.
After the widespread success of the Bordeaux mixture (a copper sulfate and lime-based fungicide discovered in the late 19th century), researchers sought to develop copper-based formulations that offered better adhesion to plant surfaces, improved rain resistance, and reduced phytotoxicity.
This led to the synthesis and commercial introduction of copper oxychloride fungicides around the 1920s and 1930s.
Copper oxychloride became especially popular because of its relatively fine particle size, allowing better suspension in water and more uniform crop coverage compared to older mixtures.
Over time, copper oxychloride became a cornerstone in fungal and bacterial disease management, particularly in vineyards, citrus orchards, and vegetable farming.
As awareness grew regarding environmental accumulation of heavy metals, regulatory limits on copper usage were introduced from the late 20th century onward, leading to refined formulations with optimized copper concentrations and application guidelines.
Despite regulatory pressures, copper oxychloride remains a critical tool in integrated pest management, valued for its broad-spectrum protection and compatibility with organic farming practices.
Handling and Storage of Copper Oxychloride:
Handle copper oxychloride carefully to avoid the generation of dust.
Use personal protective equipment (PPE) including gloves, safety goggles, and dust masks during handling.
Store in a cool, dry, well-ventilated area, away from direct sunlight, moisture, and incompatible substances such as strong acids and strong oxidizing agents.
Keep containers tightly closed and properly labeled.
Avoid contamination of soil and waterways during storage or transfer.
Reactivity and Stability of Copper Oxychloride:
Stability:
Copper oxychloride is stable under normal conditions of use and storage.
Reactivity:
Copper oxychloride is incompatible with strong acids, which can release toxic fumes of hydrogen chloride gas.
Decomposition:
At elevated temperatures, Copper oxychloride may decompose to release irritating and toxic gases including hydrogen chloride and copper oxides.
Conditions to Avoid:
Excessive heat, strong acids, and strong oxidizers.
First Aid Measures of Copper Oxychloride:
Inhalation:
Move the person to fresh air.
If breathing is difficult, give oxygen and seek medical attention.
Skin Contact:
Wash thoroughly with soap and water.
Remove contaminated clothing.
Seek medical advice if irritation develops.
Eye Contact:
Immediately flush eyes with plenty of water for at least 15 minutes.
Seek medical attention if irritation persists.
Ingestion:
Rinse mouth with water.
Do not induce vomiting.
Seek immediate medical assistance.
Firefighting Measures of Copper Oxychloride:
Suitable Extinguishing Media:
Water spray, dry chemical powder, foam, or carbon dioxide (CO₂).
Hazardous Combustion Products:
Copper oxides, hydrogen chloride gas.
Firefighting Instructions:
Wear self-contained breathing apparatus (SCBA) and full protective clothing.
Prevent runoff from entering waterways, as contaminated water can cause environmental damage.
Explosion Risk:
Copper oxychloride itself is not flammable, but containers may burst under heat.
Accidental Release Measures of Copper Oxychloride:
Personal Precautions:
Wear appropriate protective equipment (gloves, goggles, dust mask). Avoid creating dust.
Environmental Precautions:
Prevent release into drains, watercourses, and soil.
Methods for Clean-up:
Sweep up carefully without generating dust.
Collect into properly labeled containers for disposal according to local regulations.
Wash contaminated area with water while containing runoff.
Exposure Controls / Personal Protective Equipment of Copper Oxychloride:
Engineering Controls:
Ensure adequate ventilation, especially in enclosed areas.
Use local exhaust ventilation if dust is generated.
Personal Protective Equipment (PPE):
Eye/Face Protection:
Safety goggles or face shield.
Skin Protection:
Protective gloves (nitrile or rubber) and protective clothing.
Respiratory Protection:
Approved dust mask or respirator (e.g., NIOSH-approved P2 or P3 filters) if dust levels are high.
General Hygiene:
Wash hands and face after handling.
Remove contaminated clothing before eating, drinking, or smoking.
Identifiers of Copper Oxychloride:
CAS Number: 1332-65-6
ChemSpider: 10142932
ECHA InfoCard: 100.014.158
EC Number: 215-572-9
PubChem CID: 11969527
UNII: 76712031PG
CompTox Dashboard (EPA): DTXSID6034475
InChI: InChI=1S/ClH.2Cu.3H2O/h1H;;;3*1H2/q;2*+2;;;/p-4
Key: SKQUUKNCBWILCD-UHFFFAOYSA-J
SMILES: [OH-].[OH-].[OH-].[Cl-].[Cu+2].[Cu+2]
Empirical Formula: H6Cl2Cu4O6
CAS Number: 1332-40-7
Molecular Weight: 427.13
MDL number: MFCD00151229
UNSPSC Code: 12161600
PubChem Substance ID: 329783570
CAS Number: 1332-65-6
EC Number: 215-572-9
Molecular Formula: Cu₂(OH)₃Cl
Molar Mass: 213.56 g/mol
PubChem CID: 16211252
ChemSpider ID: 13149803
UNII: 5N8616SVN4
InChI: InChI=1S/2Cu.ClH.3H2O/h;;1H;3*1H2/q2*+2;;;/p-2
InChI Key: AYWVBUJSZQQOCG-UHFFFAOYSA-L
SMILES: [OH-].[OH-].[OH-].[Cl-].[Cu+2].[Cu+2]
Properties of Copper Oxychloride:
Chemical formula: Cu2(OH)3Cl
Molar mass: 213.56 g·mol−1
Appearance: Green crystalline solid
Density: 3.5 g/cm3
Melting point: 250 °C; 482 °F; 523 K
Solubility in water: Insoluble in water (pH 6.9 measured by EPA method SW846-9045)
Solubility: Insoluble in organic solvents
form: solid
reaction suitability:
core: copper
reagent type: catalyst
SMILES string: O[Cu]O.O[Cu]O.O[Cu]O.Cl[Cu]Cl
InChI: 1S/2ClH.4Cu.6H2O/h2*1H;;;;;6*1H2/q;;4*+2;;;;;;/p-8
InChI key: JNPOSJBMZIQEKM-UHFFFAOYSA-F
Molecular Weight: 249.02 g/mol
Hydrogen Bond Donor Count: 3
Hydrogen Bond Acceptor Count: 5
Rotatable Bond Count: 0
Exact Mass: 246.805119 Da
Monoisotopic Mass: 246.805119 Da
Topological Polar Surface Area: 3 Ų
Heavy Atom Count: 7
Complexity: 0
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 7
Compound Is Canonicalized: Yes
Molecular weight: 427.1.
Physical form: Green to bluish-green powder.
Composition: Contains 57% Cu++.
Melting point: decomp. 300 °C;
Vapour pressure: Negligible at 20 °C;
Solubility: In water <10-5 mg/l (pH 7, 20 °C).
Stability: Very stable in neutral media.
Specifications of Copper Oxychloride:
Chemical Formula: Cu₂(OH)₃Cl
Molecular Weight: 213.56 g/mol
Copper Content (as Cu): Typically 50–58%
Appearance: Fine light green to bluish-green crystalline powder
Odor: Odorless
pH of 1% Suspension: 6.0–8.0
Bulk Density: Approximately 0.6–0.9 g/cm³
Particle Size Distribution: ≥ 90% of particles pass through 325 mesh (approximately 45 microns)
Moisture Content: ≤ 2.0% (typically controlled during production)
Suspensibility (for formulated products): ≥ 80%
Wettability: Should wet completely within 60 seconds
Common Formulations:
Wettable Powder (WP): 85% or 50% Copper Oxychloride
Suspension Concentrate (SC): 35–40% active ingredient
Heavy Metal Impurities:
Lead (Pb): < 0.005%
Arsenic (As): < 0.0005% (Values depend on regulatory standards and intended markets.)
Structure of Copper Oxychloride:
Crystal structure:
Atacamite: orthorhombic
Paratacamite: rhombohedral
Clinoatacamite: monoclinic
Botallackite: monoclinic
Coordination geometry: Distorted octahedral
Names of Copper Oxychloride:
IUPAC name:
Dicopper(II) chloride trihydroxide
Preferred IUPAC name:
Copper trihydroxyl chloride
