Phosphorus is a nonmetallic chemical element that is a member of Group VA in the periodic table. The chemical symbol for phosphorus is P, its atomic number is 15, and its atomic weight is 30.975. Phosphorus was first prepared by German alchemist Hennig Brandt in 1669, in the course of his search for the philosopher's stone he obtained from a residue of evaporated urine a white solid that glowed in the dark and ignited spontaneously in air. The name phosporus (from the Greek for "light bringing"), which at that time was used for any substance that glows of itself, was eventually appropriated to this element. Phosphorus does not occur in elemental form in nature; it is found most commonly in apatite minerals such as fluorapatite.
There are white phosphorus, black phosphorus and red phosphorus. Red phosphorus is considered as mixture of black phosphorus and white phosphorus. See the picture of each kind of phosphorus:
About ten forms of the element are known. White phosphorus consists of molecular P4 and is waxlike substance, very toxic and extremely flammable. When it is exposed to air in the dark, it emits a greenish light and gives off white fumes. It can ignite spontaneously. White phosphorus is used in incendiary and napalm bombs and in rat poison.
Red phosphorus, a more stable form than white, can be obtained by heating white phosphorus to 250oC in a closed vessel. Red phosphorus is often considered a mixture of white and black phosphorus. It nether phosphoresces nor spontaneously burns in air. It is used in industry as part of the coating industry of safety matches and in the manufacture of tracer bullets, smoke screens, and sky writing compound.
When heated to temperature near 300oC for several days, red phosphorus is converted to black phosphorus. Black phosphorus is flaky, like graphite, and has some metallic properties. It is the least reactive of the forms.
Nearly all the phosphorus used in commerce is in the form of phosphates, the salt derived from phosphoric acid, H3PO4. Large amounts of phosphate containing fertilizer are used to enhance soil fertility. Sodium triphosphate, Na5P3O10 is used in detergents because, it softens water and disperses inorganic soiling substances. A serious disadvantage of using phosphates later end up in natural bodies of water, where to proliferate. Phosphates are also used in toothpases, Ca(H2PO4)2, and sodium acid pyrophosphate, Na2H2P2O7, are leavening agents used in taking powder.
Phosphorus, exclusively in the form of phosphates, is found in all forms of the Phosphates are essential to the energy transfer reactions necessary to sustain life processes, to a number of coenzymes, and to nucleic acids.
Phosphates are also important ingredients of bone, the human skeleton contains about 1.4 kg (about 3 lb) of phosphates as calcium phosphates, Ca3(PO4)2. A phosphorus deficiency causes fatigue, weakness, and a decreased attention span. A severe deficiency may lead to seizures, coma or even death.
There are white phosphorus, black phosphorus and red phosphorus. Red phosphorus is considered as mixture of black phosphorus and white phosphorus. See the picture of each kind of phosphorus:
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| White phosphorus |
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| Red phosphorus |
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| Black Phosphorus |
Allotropes of Phosphorus
About ten forms of the element are known. White phosphorus consists of molecular P4 and is waxlike substance, very toxic and extremely flammable. When it is exposed to air in the dark, it emits a greenish light and gives off white fumes. It can ignite spontaneously. White phosphorus is used in incendiary and napalm bombs and in rat poison.
Red phosphorus, a more stable form than white, can be obtained by heating white phosphorus to 250oC in a closed vessel. Red phosphorus is often considered a mixture of white and black phosphorus. It nether phosphoresces nor spontaneously burns in air. It is used in industry as part of the coating industry of safety matches and in the manufacture of tracer bullets, smoke screens, and sky writing compound.
When heated to temperature near 300oC for several days, red phosphorus is converted to black phosphorus. Black phosphorus is flaky, like graphite, and has some metallic properties. It is the least reactive of the forms.
Phosphates
Nearly all the phosphorus used in commerce is in the form of phosphates, the salt derived from phosphoric acid, H3PO4. Large amounts of phosphate containing fertilizer are used to enhance soil fertility. Sodium triphosphate, Na5P3O10 is used in detergents because, it softens water and disperses inorganic soiling substances. A serious disadvantage of using phosphates later end up in natural bodies of water, where to proliferate. Phosphates are also used in toothpases, Ca(H2PO4)2, and sodium acid pyrophosphate, Na2H2P2O7, are leavening agents used in taking powder.
Biological Role of Phosphorus
Phosphorus, exclusively in the form of phosphates, is found in all forms of the Phosphates are essential to the energy transfer reactions necessary to sustain life processes, to a number of coenzymes, and to nucleic acids.
Phosphates are also important ingredients of bone, the human skeleton contains about 1.4 kg (about 3 lb) of phosphates as calcium phosphates, Ca3(PO4)2. A phosphorus deficiency causes fatigue, weakness, and a decreased attention span. A severe deficiency may lead to seizures, coma or even death.
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