Copper(II) fluoride or cupric fluoride is an

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the chemical formula CuF₂. The

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...

form is a white, ionic, crystalline,

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

salt with a distorted

rutile Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest refractive indices at vis ...

-type

crystal structure In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat ...

, similar to other fluorides of chemical formulae MF₂ (where M is a metal). The

dihydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...

, , is blue in colour.

Structure

Copper(II) fluoride has a monoclinic crystal structure and cannot achieve a higher-symmetry structure. It forms rectangular prisms with a parallelogram base. Each copper ion has four neighbouring fluoride ions at 1.93 Å separation and two further away at 2.27 Å. This distorted octahedral +2

coordination Coordination may refer to: * Coordination (linguistics), a compound grammatical construction * Coordination complex, consisting of a central atom or ion and a surrounding array of bound molecules or ions ** A chemical reaction to form a coordinati ...

is a consequence of the Jahn–Teller effect in d⁹ copper(II), and leads to a distorted rutile structure similar to that of chromium(II) fluoride, , which is a d⁴ compound.

Uses

Cupric fluoride catalyzes the decomposition of nitric oxides in emission control systems. Copper (II) fluoride can be used to make fluorinated aromatic hydrocarbons by reacting with

aromatic hydrocarbon Aromatic compounds or arenes are organic compounds "with a chemistry typified by benzene" and "cyclically conjugated." The word "aromatic" originates from the past grouping of molecules based on odor, before their general chemical properties were ...

s in an

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

-containing atmosphere at temperatures above 450 °C (842 °F). This reaction is simpler than the Sandmeyer reaction, but is only effective in making compounds that can survive at the temperature used. A coupled reaction using oxygen and 2 HF regenerates the copper(II) fluoride, producing water. This method has been proposed as a "greener" method of producing fluoroaromatics since it avoids producing toxic waste products such as ammonium fluoride. :

Chemistry

Copper(II) fluoride can be synthesized from

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

and

fluorine Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extre ...

at temperatures of 400 °C (752 °F). It occurs as a direct reaction. : Cu + F₂ → CuF₂ It loses fluorine in the molten stage at temperatures above 950 °C (1742 °F). : 2CuF₂ → 2CuF + F₂ : 2CuF → CuF₂ + Cu The complex anions of CuF₃⁻, CuF₄²⁻ and CuF₆⁴⁻ are formed if CuF₂ is exposed to substances containing

fluoride Fluoride (). According to this source, is a possible pronunciation in British English. is an Inorganic chemistry, inorganic, Monatomic ion, monatomic Ion#Anions and cations, anion of fluorine, with the chemical formula (also written ), whose ...

ions F⁻.

Solubility

Copper(II) fluoride is slightly soluble in water, but starts to decompose when it is in hot water, producing basic F⁻ and Cu(OH) ions.

Toxicity

There is little specific information on the toxicity of Copper(II) fluoride. Copper toxicity can affect the skin, eyes, and respiratory tract. Serious conditions include metal fume fever, and

hemolysis Hemolysis or haemolysis (), also known by #Nomenclature, several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may ...

of red blood cells. Copper can also cause damage to the liver and other major organs. Metal fluorides are generally safe at low levels and are added to water in many countries to protect against tooth decay. At higher levels they can cause toxic effects ranging from nausea and vomiting to tremors, breathing problems, serious convulsions and even coma. Brain and kidney damage can result. Chronic exposure can cause losses in bone density, weight loss and anorexia.

Hazards

Experiments using copper(II) fluoride should be conducted in a fume hood because metal oxide fumes can occur. The combination of acids with copper(II) fluoride may lead to the production of

hydrogen fluoride Hydrogen fluoride (fluorane) is an Inorganic chemistry, inorganic compound with chemical formula . It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluori ...

, which is highly toxic and corrosive.

References

* * * *Dierks, S. "Copper Fluoride". http://www.espimetals.com/index.php/msds/537-copper-fluoride (accessed October 9). * * * *

External links

National Pollutant Inventory - Copper and compounds fact sheet
{{DEFAULTSORT:Copper(Ii) Fluoride Fluorides Metal halides Copper(II) compounds