Phosphorus

Phosphorus is a chemical element with atomic number 15 in the third period of the periodic system of elements. This is one of the most common elements of the earth's crust: its content is 0,08-0,09% of its mass. The concentration of phosphorus in sea water is 0,07 mg/l. In a free state phosphorus does not occur because of high chemical activity. It is in about 190 minerals, the most important of which are apatite and phosphorite. Phosphorus is found in all green parts of the plant, even more in its fruits and seeds found in the tissues of animals, it is part of the protein and other essential organic compounds.

Phosphorus is a chemical element with atomic number 15 in the third period of the periodic system of elements

Phosphorus was discovered alchemist Hennig Brand in 1669. Brand, conducting experiments with human urine, trying to find the philosopher's stone, and received glowing substance. At first the urine to stand for several days until an unpleasant smell will disappear, and then boiled until sticky state. By heating it to high temperatures and bringing to the appearance of bubbles, he is hoped, that by condense, it contain gold. After several hours of intense boiling grains obtained white waxy substance that burned brightly and also flickered in the dark. Brand named this substance phosphorus mirabilis.

Today phosphorus is obtained from phosphate apatite, or by reaction with coke and silica at a temperature of about 16000 C. It is easily oxidized by oxygen. Additionally, it interacts with many simple substances - halogens, sulfur, some metals, exhibiting redox properties. With hydrogen a phosphorus virtually not connected.

Phosphorus has many modifications. At low temperatures, there is a colorless phosphorus, which resembles diamond crystals. The most common under normal conditions, white and red phosphorus. Red can be extracted from white, if it is a long time to heat up to 250 degrees Celsius without air access. It is much more difficult to oxidize than white, especially, very slowly oxidized by atmospheric oxygen. This yields hygroscopic products, from which the red phosphorus is raw. The wet red phosphorous on the filter was washed with hot water and thoroughly dried in a drying cabinet.

If white phosphorus is heated at 200 degrees Celsius under pressure of 12000 atm, it is possible to produce black phosphorus, which resembles graphite.

Under pressure from its only pair of black phosphorus above 550 degrees Celsius becomes purple phosphorus. Last phosphorus mined by heating white phosphorus under a pressure of 500 atm. In addition, there is a ruby, purple and brown phosphorus.

Phosphorus is an essential nutrient element and at the same time is very widely used in industry. Red phosphorus is used in the manufacture of matches. Furthermore, phosphorus is used to passivate the metal surface, means for water softening.

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