Copper oxide

Cuprum (Cu) refers to the number of low-activity metals. It is characterized by the formation of chemical compounds with degrees of oxidation +1 and +2. So, for example, two oxides, which are a combination of two elements of Cu and oxygen O: with oxidation state +1 - copper oxide Cu2O and oxidation state +2 - copper oxide CuO. Despite the fact that they consist of the same chemical elements, but each of them has its own special characteristics. In the cold, the metal very weakly interacts with the oxygen of the air, covering with a copper oxide film, which prevents the further oxidation of the cuprum. When heated, this simple substance with the ordinal number 29 in the periodic table is completely oxidized. In addition, copper (II) oxide is also formed: 2Cu + O2 → 2CuO.

The nitrous oxide is a brownish-red solid with a molar mass of 143.1 g / mol. The compound has a melting point of 1235 ° C, a boiling point of 1800 ° C. It does not dissolve in water, but dissolves in acids. Copper oxide (I) is diluted in a solution of ammonia (concentrated), thus forming a colorless complex of [Cu (NH3) 2] +, which is easily oxidized in air to a blue-violet ammonium complex [Cu (NH3) 4 (H2O) 2] 2+, which dissolves in hydrochloric acid to form CuCl2. In the history of semiconductor physics, Cu2O is one of the most studied materials.

Copper oxide (I), also known as hemioxide, has basic properties. It can be obtained by oxidizing the metal: 4Cu + O2 → 2 Cu2O. Admixtures such as water and acids affect the rate of this process, as well as further oxidation to the bivalent oxide. The copper oxide can dissolve in sulfuric acid, thus forming a pure metal and salt: H2SO4 + Cu2O → Cu + CuSO4 + H2O. In a similar scheme, the oxide interacts with the degree of oxidation of the metal +1 with other oxygen-containing acids. When the hemioxide interacts with halogen-containing acids, monovalent metal salts are formed: 2HCl + Cu2O → 2CuCl + H2O.

There is copper oxide (I) in nature in the form of red ore (this is an outdated name, along with ruby Cu, for example), called the "Kuprite" mineral. His education takes a long time. It can be obtained artificially at high temperatures or under high oxygen pressure. Hemioksid is commonly used as a fungicide, as a pigment, as an anti-fouling agent in underwater or marine paint, and is also used as a catalyst.

However, exposure to this substance with the chemical formula Cu2O on the body can be dangerous. When inhaled, it causes shortness of breath, cough, and ulceration and perforation of the respiratory tract. If ingested, irritates the gastrointestinal tract, which is accompanied by vomiting, pain and diarrhea.

The highest oxide of copper in appearance is a powder from brown to black. In nature, in pure form, it occurs as a mineral "Tenorite". The melting point is 1326 ° C, the boiling point is 2000 ° C. It is insoluble in water, alcohol, ammonium hydroxide, ammonium carbonate solution. Soluble in aqueous solutions of ammonium chloride and potassium cyanide. This black solid can be obtained by heating Cu in air. However, in this case, also formed by the oxide of Cu. The preparation of CuO is possible by heating the compounds:

• Copper (II) nitrate 2Cu (NO3) 2 → 4 NO2 + O2 + 2CuO;

• Copper (II) hydroxide Cu (OH) 2 → H2O + CuO;

• Copper (II) carbonate CuCO3 → CO2 + CuO.

Cuprum (II) oxide is basic, so it dissolves in mineral acids (hydrochloric, sulfuric and nitric) to obtain the corresponding bivalent Cu salt:

• 2HCl + CuO → CuCl2 + H2O;

• H2SO4 + CuO → CuSO4 + H2O;

• 2HNO3 + CuO → Cu (NO3) 2 + H2O.

Reacts copper (II) oxide with concentrated alkali to form a salt: 2 KOH + CuO + H2O → K2 [Cu (OH) 4].

Oxide can also be reduced to metallic Cu by reaction with hydrogen or carbon monoxide :

• H2 + CuO → Cu + H2O;

• CO + CuO → Cu + CO2.

Copper (II) oxide is used in ceramics (as a pigment) to produce glaze (blue, green and red, and sometimes pink, gray or black). It is also used as a food supplement in animals to reduce the deficiency of cuprum in the body. This is an abrasive material that is necessary for polishing optical equipment. It is used to produce dry batteries, to produce other Cu salts. The CuO compound is also used in the welding of copper alloys.

The effect of a chemical compound CuO can also be dangerous for the human body. Inhalation causes irritation of the lungs. Copper (II) oxide can cause fever of metallic vapors (MFF). Cu oxide provokes a discoloration of the skin, there may be problems with vision. When ingested, like hemioxide, leads to poisoning, which is accompanied by symptoms in the form of vomiting and pain.