Names | |
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IUPAC name Copper(II) hydroxide | |
Other names Cupric hydroxide | |
Identifiers | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.039.817 |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
Cu(OH)2 | |
Molar mass | 97.561 g/mol |
Appearance | Blue or blue-green solid |
Density | 3.368 g/cm3, solid |
Melting point | 80 °C (176 °F; 353 K) approximate, decomposes into CuO |
negligible | |
Solubility product (Ksp) | 2.20 x 10−20 [1] |
Solubility | insoluble in ethanol; soluble in NH4OH |
+1170.0·10−6 cm3/mol | |
Thermochemistry | |
Std molar entropy (S⦵298) | 108 J·mol−1·K−1 |
Std enthalpy of formation (ΔfH⦵298) | −450 kJ·mol−1 |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | Skin, Eye, & Respiratory Irritant |
NFPA 704 (fire diamond) | |
Flash point | Non-flammable |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 1000 mg/kg (oral, rat) |
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) | SDS |
Related compounds | |
Other anions | Copper(II) oxide Copper(II) carbonate Copper(II) sulfate Copper(II) chloride |
Other cations | Nickel(II) hydroxide Zinc hydroxide Iron(II) hydroxide Cobalt hydroxide |
Related compounds | Copper(I) oxide Copper(I) chloride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
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.
Copper(II) hydroxide has been known since copper smelting began around 5000 BC although the alchemists were probably the first to manufacture it by mixing solutions of lye (sodium or potassium hydroxide) and blue vitriol (copper(II) sulfate). [3] Sources of both compounds were available in antiquity.
It was produced on an industrial scale during the 17th and 18th centuries for use in pigments such as blue verditer and Bremen green. [4] These pigments were used in ceramics and painting. [5]
The mineral of the formula Cu(OH)2 is called spertiniite. Copper(II) hydroxide is rarely found as an uncombined mineral because it slowly reacts with carbon dioxide from the atmosphere to form a basic copper(II) carbonate. Thus copper slowly acquires a dull green coating in moist air by the reaction:
The green material is in principle a 1:1 mole mixture of Cu(OH)2 and CuCO3. [6] This patina forms on bronze and other copper alloy statues such as the Statue of Liberty.
Copper(II) hydroxide can be produced by adding sodium hydroxide to a solution of a soluble copper(II) salt, such as copper(II) sulfate (CuSO4·5H2O): [7]
The precipitate produced in this manner, however, often contains water and an appreciable amount of sodium-containing impurities. Furthermore, this form of copper hydroxide tends to convert to black copper(II) oxide: [8]
A purer product can be attained if ammonium chloride is added to the solution beforehand to generate ammonia in situ. [9] Alternatively it can be produced in a two-step procedure from copper(II) sulfate via "basic copper sulfate:" [8]
Alternatively, copper hydroxide is readily made by electrolysis of water (containing a little electrolyte such as sodium sulfate or magnesium sulfate) with a copper anode:
The structure of Cu(OH)2 has been determined by X-ray crystallography The copper center is square pyramidal. Four Cu-O distances in the plane range are 1.96 Å, and the axial Cu-O distance is 2.36 Å. The hydroxide ligands in the plane are either doubly bridging or triply bridging. [10]
It is stable to about 100 °C. [7]
Copper(II) hydroxide reacts with a solution of ammonia to form a deep blue solution of tetramminecopper [Cu(NH3)4]2+ complex ion.
Copper(II) hydroxide catalyzes the oxidation of ammonia solutions in presence of dioxygen, giving rise to copper ammine nitrites, such as Cu(NO2)2(NH3)n. [11] [12]
Copper(II) hydroxide is mildly amphoteric. It dissolves slightly in concentrated alkali, forming [Cu(OH)4]2−. [13] [7]
Copper(II) hydroxide has a rather specialized role in organic synthesis. Often, when it is utilized for this purpose, it is prepared in situ by mixing a soluble copper(II) salt and potassium hydroxide.
It is sometimes used in the synthesis of aryl amines. For example, copper(II) hydroxide catalyzes the reaction of ethylenediamine with 1-bromoanthraquinone or 1-amino-4-bromoanthraquinone to form 1-((2-aminoethyl)amino)anthraquinone or 1-amino-4-((2-aminoethyl)amino)anthraquinone, respectively: [14]
Copper(II) hydroxide also converts acid hydrazides to carboxylic acids at room temperature. This conversion is useful in the synthesis of carboxylic acids in the presence of other fragile functional groups. The yields are generally excellent as is the case with the production of benzoic acid and octanoic acid: [14]
Copper(II) hydroxide in ammonia solution, known as Schweizer's reagent, possesses the interesting ability to dissolve cellulose. This property led to it being used in the production of rayon, a cellulose fiber.
It is also used widely in the aquarium industry for its ability to destroy external parasites in fish, including flukes, marine ich, Brooklynellosis, and marine velvet, without killing the fish. Although other water-soluble copper compounds can be effective in this role, they generally result in high fish mortality.
Copper(II) hydroxide has been used as an alternative to the Bordeaux mixture, a fungicide and nematicide. [15] Such products include Kocide 3000, produced by Kocide L.L.C. Copper(II) hydroxide is also occasionally used as ceramic colorant.
Copper(II) hydroxide has been combined with latex paint, making a product designed to control root growth in potted plants. Secondary and lateral roots thrive and expand, resulting in a dense and healthy root system. It was sold under the name Spin Out, which was first introduced by Griffin L.L.C. The rights are now owned by SePRO Corp. [16] It is now sold as Microkote either in a solution you apply yourself, or as treated pots.
Together with other components, copper(II) hydroxides are numerous. Several copper(II)-containing minerals contain hydroxide. Notable examples include azurite, malachite, antlerite, and brochantite. Azurite (2CuCO3·Cu(OH)2) and malachite (CuCO3·Cu(OH)2) are hydroxy-carbonates, whereas antlerite (CuSO4·2Cu(OH)2) and brochantite (CuSO4·3Cu(OH)2) are hydroxy-sulfates.
Many synthetic copper(II) hydroxide derivatives have been investigated. [18]
An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen ion, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid.
An acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH via titration. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.
Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, a ligand, a nucleophile, and a catalyst. The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. The corresponding electrically neutral compound HO• is the hydroxyl radical. The corresponding covalently bound group –OH of atoms is the hydroxy group. Both the hydroxide ion and hydroxy group are nucleophiles and can act as catalysts in organic chemistry.
In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively charged sodium ions and negatively charged chloride ions.
The ammonium cation is a positively charged polyatomic ion with the chemical formula NH+4 or [NH4]+. It is formed by the protonation of ammonia. Ammonium is also a general name for positively charged (protonated) substituted amines and quaternary ammonium cations, where one or more hydrogen atoms are replaced by organic or other groups.
In chemistry, there are three definitions in common use of the word "base": Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century.
Basic copper carbonate is a chemical compound, more properly called copper(II) carbonate hydroxide. It is an ionic compound consisting of the ions copper(II) Cu2+
, carbonate CO2−
3, and hydroxide OH−
.
In organic chemistry, Fehling's solution is a chemical reagent used to differentiate between water-soluble carbohydrate and ketone functional groups, and as a test for reducing sugars and non-reducing sugars, supplementary to the Tollens' reagent test. The test was developed by German chemist Hermann von Fehling in 1849.
Copper(I) oxide or cuprous oxide is the inorganic compound with the formula Cu2O. It is one of the principal oxides of copper, the other being or copper(II) oxide or cupric oxide (CuO). Cuprous oxide is a red-coloured solid and is a component of some antifouling paints. The compound can appear either yellow or red, depending on the size of the particles. Copper(I) oxide is found as the reddish mineral cuprite.
Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 million tonnes, the decahydrate is a major commodity chemical product. It is mainly used as a filler in the manufacture of powdered home laundry detergents and in the Kraft process of paper pulping for making highly alkaline sulfides.
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.
Tetraamminecopper(II) sulfate is the salt with the formula [Cu(NH3)4]SO4·H2O. This dark blue to purple solid is a salt of the metal complex [Cu(NH3)4(H2O)]2+. It is closely related to Schweizer's reagent, which is used for the production of cellulose fibers in the production of rayon.
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.
A nitrate test is a chemical test used to determine the presence of nitrate ion in solution. Testing for the presence of nitrate via wet chemistry is generally difficult compared with testing for other anions, as almost all nitrates are soluble in water. In contrast, many common ions give insoluble salts, e.g. halides precipitate with silver, and sulfate precipitate with barium.
The Kjeldahl method or Kjeldahl digestion (Danish pronunciation: [ˈkʰelˌtɛˀl]) in analytical chemistry is a method for the quantitative determination of nitrogen contained in organic substances plus the nitrogen contained in the inorganic compounds ammonia and ammonium (NH3/NH4+). Without modification, other forms of inorganic nitrogen, for instance nitrate, are not included in this measurement. Using an empirical relation between Kjeldahl nitrogen content and protein content it is an important method for analyzing proteins. This method was developed by Johan Kjeldahl in 1883.
Cobalt extraction refers to the techniques used to extract cobalt from its ores and other compound ores. Several methods exist for the separation of cobalt from copper and nickel. They depend on the concentration of cobalt and the exact composition of the ore used.
Dicopper chloride trihydroxide is the chemical compound with the 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.
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.
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.