Phosphorus (revised)
PHOSPHORUS (REVISED)
Note: This article, originally published in 1998, was updated in 2006 for the eBook edition.
Overview
Phosphorus is found in Group 15 (VA) of the periodic table. The periodic table is a chart that that shows how chemical elements are related to each other. Phosphorus is part of the nitrogen family along with nitrogen, arsenic, antimony, and bismuth.
Phosphorus was first discovered in 1669 by German physician Hennig Brand (ca. 1630-92). Brand is somewhat famous in chemistry. He is sometimes called the last of the alchemists. Alchemy was a kind of pre-science that existed from about 500 B.C. to about the end of the 16th century. Alchemists wanted to find a way of changing lead, iron, and other metals into gold. They also wanted to find a way of having eternal life. Alchemy contained too much magic and mysticism to be a real science. But it developed a number of techniques and produced many new materials that were later found to be useful in modern chemistry.
SYMBOL
P
ATOMIC NUMBER
15
ATOMIC MASS
30.97376
FAMILY
Group 15 (VA)
Nitrogen
PRONUNCIATION
FOS-fer-us
Brand was convinced that the key to changing metals into gold could be found in urine. He decided to look for the "magic substance" that could change lead into gold in urine. In the process of heating and purifying urine, he obtained phosphorus. The discovery was important because it was the first time someone had discovered an element not known to ancient peoples. In that regard, Brand was the first person who could be called the discoverer of an element.
Phosphorus is a fascinating element that occurs in at least three very different forms. If left exposed to the air, it catches fire on its own. It also glows in the dark. Today, its most important use is in the manufacture of phosphoric acid (H3PO4). Phosphoric acid, in turn, is used to manufacture fertilizers and a number of other less important products.
Discovery and naming
Phosphorus and its compounds may have been known before Brand's discovery. Old manuscripts refer to materials that glow in the dark. The word used for such materials today is phosphorescent. Early Christians noted the use of "perpetual lamps" that glowed in the dark. The lamps may have contained phosphorus or one of its compounds.
Still, Brand was the first to record the process of making pure phosphorus. No one knows how he decided that urine might contain a chemical that could be used to turn lead into gold. His experiments to find such a chemical were, of course, a failure. But he made an accidental discovery along the way. That discovery was a material that glowed in the dark: phosphorus.
Scientists were fascinated when they heard of Brand's discovery. They tried to repeat his research. Some tried to talk him into selling his discovery to kings and princes. The new element seemed to be a way of getting rich and becoming famous.
But Brand was never interested in these ideas. Instead, he gave away all of the phosphorus he prepared. Other scientists soon began to experiment with the element. One of the first discoveries they made was how dangerous phosphorus is. One scientist wrote that a servant left some phosphorus on top of his bed one day. Later that night, the bed covers burst into flame. The phosphorus had caught fire by itself!
Eventually, Brand's method of making phosphorus became widely known. The element joined iron, gold, silver, arsenic, and the handful of other elements known to early chemists.
Little is known about what happened to Brand after his discovery. In fact, there is no record of where or when he died.
Physical properties
Phosphorus exists in at least three allotropic forms. Allotropes are forms of an element with different physical and chemical properties. The three main allotropes are named for their colors: white phosphorus (also called yellow phosphorus), red phosphorus, and black phosphorus (also called violet phosphorus). These allotropes all have different physical and chemical properties.
White phosphorus is a waxy, transparent solid. Its melting point is 44.1°C (111°F) and its boiling point is 280°C (536°F). It has a density of 1.88 grams per cubic centimeter. If kept in a vacuum, it sublimes if exposed to light. Sublimation is the process by which a solid changes directly to a gas when heated, without first changing to a liquid. White phosphorus is phosphorescent. It gives off a beautiful greenish-white glow. It does not dissolve well in water, although it does dissolve in other liquids, such as benzene, chloroform, and carbon disulfide. White phosphorus sometimes appears slightly yellowish because of traces of red phosphorus.
Red phosphorus is a red powder. It can be made by heating white phosphorus with a catalyst to 240°C (464°F). A catalyst is a substance used to speed up or slow down a chemical reaction without undergoing any change itself. Without a catalyst, red phosphorus sublimes at 416°C (781°F). Its density is 2.34 grams per cubic centimeter. It does not dissolve in most liquids.
Black phosphorus looks like graphite powder. Graphite is a form of carbon used in "lead" pencils. Black phosphorus can be made by applying extreme pressure to white phosphorus. It has a density of 3.56 to 3.83 grams per cubic centimeter. One of its interesting properties is that it conducts an electric current in spite of being a non-metal.
Brand was convinced that the key to changing metals into gold could be found in urine. Instead, he found phosphorus.
Chemical properties
White phosphorus is the form that occurs most commonly at room temperatures. It is very reactive. It combines with oxygen so easily that it catches fire spontaneously (automatically). As a safety precaution, white phosphorus is stored under water in chemical laboratories.
Phosphorus combines easily with the halogens. The halogens are the elements that make up Group 17 (VIIA) of the periodic table. They include fluorine, chlorine, bromine, iodine, and astatine . For example, the reaction between phosphorus and chlorine is:
Phosphorus also combines with metals to form compounds known as phosphides:
White phosphorus combines with oxygen so easily that it catches fire automatically. As a safety precaution, white phosphorus is stored under water in chemical laboratories.
Occurrence in nature
The abundance of phosphorus in the Earth's crust is estimated to be 0.12 percent, making it the 11th most common element. It usually occurs as a phosphate. A phosphate is a compound that contains phosphorus, oxygen, and at least one more element. An example is calcium phosphate, Ca3(PO4)2.
The only important commercial source of phosphorus is phosphate rock. Phosphate rock is primarily calcium phosphate. The United States is the largest producer of phosphate rock in the world. In 1996, 13,300,000 metric tons of phosphate rock were mined in the United States. That amounted to about a third of the world's total phosphate rock.
About 86 percent of phosphate rock comes from North Carolina and Florida. Smaller amounts are also mined in Idaho and Utah. Other major producers of phosphate rock are Morocco, China, Russia, Tunisia, Jordan, and Israel.
Isotopes
Only one naturally occurring isotope of phosphorus exists, phosphorus-31. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope.
Six radioactive isotopes of phosphorus are known also. A radioactive isotope is one that breaks apart and gives off some form of radiation. Radioactive isotopes are produced when very small particles are fired at atoms. These particles stick in the atoms and make them radioactive.
One radioactive isotope, phosphorus-32, has applications in medicine, industry, and tracer studies. A tracer is a radioactive isotope whose presence in a system can easily be detected. The isotope is injected into the system where it gives off radiation. The radiation is followed by means of detectors placed around the system.
Phosphorus-32 is especially useful in medical studies, because phosphorus occurs in many parts of the body. Radioactive phosphorus can be used as a tracer to study parts of the body as well as chemical changes inside the body. Radioactive phosphorus can also determine how much blood is in a person's body. It can also help locate the presence of tumors in the brain, eyes, breasts, and skin. Finally, it is sometimes used to treat certain forms of cancer. Radiation given off by the phosphorus-32 may kill cancer cells and help slow or stop the disease.
Phosphorus-32 is important in a variety of scientific studies. For example, it is added to tires when they are made. Then, the radiation it gives off can be studied as the tires are used. This information tells where the tire wears out and how long it takes to wear out.
Extraction
It is possible to make pure phosphorus from phosphate rock. The rock is mixed with sand and coke (pure carbon). The mixture is then heated in an electric furnace. An electric furnace is a device for producing very high temperatures. Pure phosphorus is produced in this reaction. It escapes from the mixture as a vapor (gas). The cooled vapor solidifies into white phosphorus. The reaction is:
Radioactive phosphorus helps locate the presence of tumors in the brain, eyes, breasts, and skin.
This reaction is not very important because pure phosphorus has few uses. The most important compounds of phosphorus are all made from phosphate rock or calcium phosphate. Therefore, the most important step in producing "phosphorus" is simply to separate pure calcium phosphate from phosphate rock. This can be done fairly easily.
Uses and compounds
In 1996, 91 percent of all the phosphate rock mined in the United States was used to make fertilizer. Modern farmers use enormous amounts of synthetic (artificial) fertilizer on their crops. This synthetic fertilizer contains nitrogen, phosphorus, and potassium, the three elements critical to growing plants. These elements normally occur in the soil, but may not be present in large enough amounts. Adding them by means of synthetic fertilizer helps plants grow better. Most farmers add some form of synthetic fertilizer to their fields every year. This demand for synthetic fertilizers accounts for the major use of phosphorus compounds.
Phosphorus and its compounds have other uses. These uses account for about 10 percent of all the phosphorus produced. For example, the compounds known as phosphorus pentasulfide (P2S5) and phosphorus sesquisulfide (P4S3) are used to make ordinary wood and paper safety matches. These compounds coat the tip of the match. When the match is scratched on a surface, the phosphorus pentasulfide or phosphorus sesquisulfide bursts into flame. It ignites other chemicals on the head of the match.
Another compound of phosphorus with a number of uses is phosphorus oxychloride (POCl3). This compound is used in the manufacture of gasoline additives, in the production of certain kinds of plastics, as a fire retardant agent, and in the manufacture of transistors for electronic devices.
Health effects
Phosphorus is essential to the health of plants and animals. Many essential chemicals in living cells contain phosphorus. One of the most important of these chemicals is adenosine triphosphate (ATP). ATP provides the energy to cells they need to stay alive and carry out all the tasks they have to perform. Phosphorus is critical to the development of bones and teeth. Nucleic acids also contain phosphorus. Nucleic acids are chemicals that perform many functions in living organisms. For example, they carry the genetic information in a cell. They tell the cell what chemicals it must make. It also acts as the "director" in the formation of those chemicals.
The daily recommended amount of phosphorus for humans is one gram. It is fairly easy to get that much phosphorus every day through meat, milk, beans, and grains.
Two phosphorus compounds are used to coat the tip of a match.
On the other hand, elemental phosphorus is extremely dangerous. Elemental phosphorus is phosphorus as an element, not combined with other elements. Swallowing even a speck of white phosphorus produces severe diarrhea with loss of blood; damage to the liver, stomach, intestines, and circulatory system(blood flow system); and coma. Swallowing a piece of white phosphorus no larger than 50 to 100 milligrams (0.0035 ounce) can even cause death.
Handling white phosphorus is dangerous as well. It causes serious skin burns.
Making lakes too healthy
T he second most important use of phosphate compounds is in making detergents. The compound most often used in detergents is called sodium tripolyphosphate, or STPP (Na5P3O10).
STPP adds a number of benefits to a detergent. For example, it can kill some bacteria and prevent washers from becoming corroded (rusted) and clogged. The most important function in detergents, however, is as a water-softening agent.
Natural water often contains chemicals that keep soaps and detergents from sudsing. They reduce the ability of soaps and detergents to clean clothes. STPP has the ability to capture these chemicals. It greatly improves the ability of soaps and detergents to make suds and clean clothes. The first detergent to use STPP was Tide, in 1947. The introduction of Tide brought about a revolution in clothes cleaning.
But STPP can create problems for the environment. After detergents have been used, they often end up in rivers and streams and, eventually, in lakes from waste water. And that's just fine for the algae that live in those lakes. Algae are tiny green plants that use phosphorus as they grow. As more detergents get into lakes, the amount of STPP increases. That means there is more phosphorus in a lake and that, in turn, means that algae begin to grow much faster.
In some cases, there is so much STPP and phosphorus in a lake that algae grow out of control, clogging the lake with algae and other green plants. The lake slowly turns into a swamp, and finally into a meadow. The lake disappears!
Many people became concerned about this problem in the 1960s. They demanded that less STPP be used in detergents. A number of cities and states banned the sale of STPP detergents. STPP production had grown rapidly from 1.10 billion pounds in 1955 to 2.44 billion pounds in 1970. But then production began to drop off. By the mid-1990s, production had dropped well below a billion pounds a year.
Interestingly, red phosphorus does not have the same effects. It is considered to be relatively safe. It is dangerous only if it contains white phosphorus mixed with it.
Phosphorus
Phosphorus
Phosphorus—an element important to all living organisms—is the second element in Group 15 of the periodic table. The elements in this group are sometimes referred to as the nitrogen family of elements. Phosphorus has an atomic number of 15, an atomic mass of 30.97376, and a chemical symbol of P.
Phosphorus forms the basis of a large number of compounds, by far the most environmentally important of which are phosphates. All plants and animals need phosphates for growth and function, and in many natural waters the production of algae and higher plants is limited by the low natural levels of phosphorus. As the amount of available phosphorus in an aquatic environment increases, plant and algal growth can increase dramatically leading to eutrophication.
Properties
Phosphorus exists in three allotropic forms, named after their colors: white (or yellow) phosphorus; red phosphorus; and black (or violet) phosphorus. White phosphorus is a waxy, transparent solid with a melting point of about 111°F (44.1°C), a boiling point of about 536°F (280°C), and a density of 1.09 ounces per cubic inch (1.88 grams per cubic centimeter). If kept in a vacuum, white phosphorus sublimes if exposed to light. White phosphorus is also phosphorescent, giving off a beautiful greenish white glow. It does not dissolve in water, although it does dissolve in many organic liquids, such as benzene, chloroform, and carbon disulfide. White phosphorus sometimes appears slightly yellowish because it contains traces of red phosphorus.
Red phosphorus is a red powder produced by heating white phosphorus in the presence of a catalyst. Red phosphorus does not melt when heated, but sublimes at a temperature of about 781°F (416°C). Its density is 1.35 ounces per cubic inch (2.34 grams per cubic centimeter). It does not dissolve in most liquids.
Black phosphorus looks like graphite. It can be made by exposing the white allotrope of phosphorus to high pressures. The black allotrope has a density of 2.06 to 2.21 ounces per cubic inch (3.56 to 3.83 grams per cubic centimeter). One of its unusual properties is that it conducts an electric current (a common property of metals) even though it is a nonmetal.
White phosphorus is the most active form of the element, with a tendency to catch fire spontaneously at room temperature. For this reason, white phosphorus is usually stored under water in chemical laboratories as a safety precaution. All allotropes of phosphorus also combine with the halogens and with metals to form compounds known as phosphides: 3Mg + 2P → Mg3P2 (magnesium phosphide).
Occurrence and Extraction
The abundance of phosphorus in the Earth’s crust is estimated to be 0.12%, making it the 11th most common element. Its estimated crustal abundance is 1.68 x 10-2 ounces per pound (1.05 x 103 milligrams per kilogram). It usually occurs as a phosphate, such as calcium phosphate [Ca3(PO4)2], the major component of phosphate rock. The United States is the largest producer of phosphate rock in the world, with about 13,000,000 metric tons being mined each year. That amount is about a third of the world’s total phosphate rock. Nearly 90% of phosphate rock comes from two states: North Carolina and Florida. Other producers of phosphate rock include Morocco, China, Russia, Tunisia, Jordan, and Israel. Phosphorus’s estimated oceanic abundance is 8 x 10-6 ounces per gallon (6 x 10-2 milligrams per liter).
Discovery and Naming
Phosphorus was discovered in 1669 by the German physician and alchemist Hennig Brand (c. 1630–c. 1692). Brand is famous in the history of chemistry as being the last of the alchemists. Brand was convinced that the key to changing base metals into gold could be found in human urine. In the process of heating and purifying urine for his experiments, he obtained a white wax substance that glowed in the dark. The element was named for this phenomenon, the process of phosphorescence. In fact, phosphorus comes from the Greek word phosphoros meaning light bearing. It was given this name because many of its compounds are phosphorescent; that is, they store light and emit it later.
The dangerous properties of elemental phosphorus were discovered early in Brand’s research. The story is told that one of his servants left some phosphorus on top of Brand’s bed. Later that night, the bed covers burst into flame when the phosphorus caught fire spontaneously.
Uses
Elemental phosphorus has relatively few uses because of its tendency to ignite spontaneously. However, many of its compounds are widely used. More than 90% of all phosphate rock mined in the United States is converted to synthetic fertilizer. Phosphorus is one of three macronutrients needed by growing plants, the other two being nitrogen and potassium. The production of synthetic fertilizers to meet the needs of farmers in the United States and around the world is now by far the greatest application for compounds of phosphorus.
Another familiar, although much less important, use of phosphorus is the manufacture of wood and paper safety matches. Phosphorus pentasulfide (P2S5) and phosphorus sesquisulfide (P4S3) are used to coat the tip of the match, providing a material that ignites easily when scratched. Another compound of phosphorus with many uses is phosphorus oxychloride (POCl3), which is used in the manufacture of gasoline additives, in the production of certain kinds of plastics, as a fire retardant agent, and in the manufacture of transistors for electronic devices.
Health Issues
Phosphorus is essential to the health of plants and animals. One of the most important compounds in living cells is adenosine triphosphate (ATP), an energy-carrying molecule that makes possible many of the chemical reactions that take place in cells. Phosphorus is also critical to the development of strong bones and teeth in the form of the compound fluorapatite. Finally, phosphorus is a critical component of nucleic acids that carry genetic information in cells and that provide the instructions which direct the activities of those cells.
On the other hand, elemental phosphorus is highly toxic. Swallowing even a speck of white phosphorus can cause diarrhea with loss of blood; damage to the liver, stomach, intestines, and circulatory system; and coma. A piece of white phosphorus no larger than 50 to 100 milligrams (about 0.0035 ounce) can even cause death. Interestingly, red phosphorus seems to be much less toxic than white phosphorus.
In the past, one of the major contributors to phosphorus pollution was household detergents containing phosphates. These substances have now been banned from these products. Other contributors to phosphorus pollution are sewage treatment plants and runoff from cattle feedlots. (Animal feces contain significant amounts of phosphorus.) Erosion of farmland treated with phosphorus fertilizers or animal manure also contributes to eutrophication and water pollution.
See also Phosphoric acid; Phosphorus removal.
Phosphorus
Phosphorus
Description
Phosphorus (chemical symbol P) is a mineral discovered by the German alchemist Henig Brand in 1699. It plays an essential part in multiple biochemical reactions for both plants and animals and is essential to all life. Phosphorus is found in living things, in soil and rock, mostly as chemical compounds known as phosphates. Rock and soil phosphorus are mined extensively throughout the world, but especially in the Peoples' Republic of China and the United States.
Phosphorus extracted from rock is classified as either white, red or black. White (also called yellow or common) phosphorus is a wax-like substance created by heating phosphate rock until it vaporizes and the condensation solidifies. One of this form's characteristics has given the English language the adjective phosphorescent, from white phosphorus's capacity to glow in the dark when exposed to air.
White phosphorus is highly toxic, causes burns if it comes in contact with skin, and is so combustible that it has to be stored underwater for safety. Red phosphorus is a rust-colored powder created by heating white phosphorus and exposing it to sunlight. It is not as combustible as the white form. Black phosphorus is made by heating white phosphorus under extremely high pressure until it resembles graphite.
In plants, phosphorus is necessary for photosynthesis to take place. In the human body, phosphorus works in tandem with another element, calcium , in much the same way that two other electrolyte components, sodium
KEY TERMS
Anorexia nervosa —A serious and sometimes fatal eating disorder characterized by intense fear of being fat and severe weight loss. It primarily affects teenage and young adult females. Sufferers have a distorted body image wherein they see themselves as being fat even when they are at normal weight or even emaciated.
Bulimia —An eating disorder characterized by bouts of gross overeating usually followed by self-induced vomiting.
Calcitonin —A hormone produced by the thyroid gland that controls the calcium level in the blood. It does this by slowing the rate that calcium is lost from bone.
Deciliter —A fluid measurement that is equal to one-tenth of a liter, or 100 cubic centimeters (27 fluid drams or teaspoonfuls).
Diabetic ketoacidosis —A potentially serious condition in which ketones become present in the blood stream because of the metabolism of fats burned in lieu of carbohydrates that would normally be used. This occurs because there is insufficient insulin available to cause carbohydrates to be used as fuel.
Electrolyte —Substances that split into ions, or electrically-charged particles, within the body to regulate many important bodily processes. Examples of electrolytes would be sodium, potassium, hydrogen, magnesium, calcium, bicarbonate, phosphates, and chlorides.
Multiple endocrine neoplasia —Tumor formation characterized by a progressive, abnormal multiplication of cells that are not necessarily malignant in any of the glands that secrete chemicals directly into the blood stream, such as the thyroid gland, adrenal glands, or ovaries.
Osteomalacia —Softening, weakening, and removal of the minerals from bone in adults caused by vitamin D deficiency.
Osteoporosis —Loss of formative protein tissue from bone, causing it to become brittle and easily fractured. It is considered to be a normal part of aging, but does have hormonal causes that make it much more common in women than men.
Sarcoidosis —A rare disease of currently unknown cause that occurs mostly in young adults. Inflammation occurs in the lymph nodes and other tissues throughout the body, usually including the lungs, liver, skin, and eyes.
and potassium, do. Though phosphorus is found in every cell of the human body and accounts for 1% of the body's total weight, its primary function is working in conjunction with calcium to form teeth and bones.
Eighty-five percent of the phosphorus found in the body is located in these structures. In a delicately balanced chemical reaction, substances known as PTH (parathyroid hormone), calcitonin, and 25-dihydroxy vitamin D regulate the absorption of both calcium and phosphorus from the intestinal tract, thus making it available for the production of bones and teeth. If an excessive amount of phosphorus is absorbed, this will result in the phosphorus combining with all available calcium and preventing the calcium's efficient use in making and maintaining bones and teeth.
PTH balances the proportions of calcium and phosphorus in the body by increasing the release of calcium and phosphate from bone and the loss of phosphorus via the kidneys while limiting the excretion of calcium. PTH also increases the activity of the 25-dihydroxy vitamin D, which, in contrast, increases the absorption of both phosphorus and calcium from the intestinal tract.
General use
White phosphorus is a component of fertilizers, detergents and water softeners. It is also used in the manufacture of steel, plastics, insecticides, medical drugs, and animal feeds. Both white and red phosphorus are used in the making of safety matches and pesticides, including rat poison.
But the 15% of this element found in the blood stream and in other soft tissue also has a highly significant part to play in a variety of other body functions. Working with vitamin B, phosphorus is involved in the metabolism of fats and carbohydrates , in both the repair of damaged cells and tissues and the routine maintenance of healthy ones. Phosphorus is necessary for the regularity of the heartbeat, and aids in the contraction of all other muscles throughout the body. Phosphorus is needed for the functioning of the kidneys and plays a part in the conduction of impulses along the network that makes up the nervous system.
Preparations
According to the American Dietetic Association, phosphorus intake in the United States is generally above what is needed, and in recent years has actually increased. Therefore, under normal circumstances with normal food intake, there is seldom if ever a need to supplement intake of phosphorus. Persons suffering from eating disorders such as anorexia and bulimia can be deficient in phosphorus intake as well as other nutrients. As the best source of phosphorus is in protein foods such as meat, eggs, and milk products. Some vegetarians may also need to evaluate their intake of this element. Excess consumption of processed foods, and inadequate intake of whole foods, plus fertilizers and pesticides are some of the causes for excess phosphorus.
Beside high-protein foods, phosphorus is also found in decreasing quantities in whole grain breads and cereals, especially unprocessed ones, and in minute amounts in fruits and vegetables. The phosphorus present in whole grain breads and cereals, however, exists as a substance called phytin. Phytin combines with calcium to create a salt that the human body is incapable of absorbing, thus making unprocessed, unenriched grains a negligible source of phosphorus. But both commercially prepared cereals and breads may provide this element as they are frequently enriched with it. Phosphates can also be taken by mouth as a tablet.
Precautions
White phosphorus is poisonous. Red phosphorus is not. As noted, white phosphorus is a highly toxic, flammable substance capable of burning the skin if it makes contact, and of igniting at room temperature. It should be handled with extreme care. Accidental phosphorus poisoning can happen from both fertilizers and pesticides. Phosphates sometimes are leached into water systems through sewage and can drastically alter the chemical makeup of lakes and rivers. In sufficient quantities, they can lead to the death of nearly all forms of aquatic life.
A normal blood serum level of phosphorus is 2.4–4.1 mg per deciliter of blood. An abnormal serum phosphorus level should be evaluated by a physician.
Phosphorus levels higher than normal can indicate a diet that includes an excessive phosphorus intake, inadequate intake of calcium, or lack of PTH (parathyroid hormone) in the system. It can be related to bone metastasis associated with cancer , liver or kidney disease, or sarcoidosis.
Serum phosphorus levels that are below normal can be related to insufficient phosphorus or vitamin D in one's diet leading to rickets in children and osteomalacia in adults. Disorders of the parathyroid gland, causing it to secrete excessive quantities of PTH, or of the pancreas , causing it to secrete too much insulin, also affect blood levels of phosphorus. Diabetic ketoacidosis or too much calcium are other possible causes. Multiple endocrine neoplasia (MEN) is yet another condition that often is associated with lower than normal levels of phosphorus.
Side effects
Phosphorus preparations taken to supplement low phosphorus levels in the body can cause diarrhea .
Interactions
Antacids can decrease the absorption of phosphorus. Laxatives and enemas that contain the chemical compound sodium phosphate and excessive intake of vitamin D can increase phosphorus levels in the body. Administration of intravenous glucose solutions will cause phosphorus to combine with the glucose that is being absorbed by the cells.
Resources
BOOKS
Busch, Marianna A., Ph.D. Phosphorus, World Book. Chicago: World Book, Inc., 1999.
Clayman, Charles B., MD. The American Medical Association Home Medical Encyclopedia. New York: Random House, 1989.
PERIODICALS
Affenito, Sandra G., pH, RD, and Jane Kerstetter, pH, RD. "Position of the American Dietetic Association and Dietitians of Canada: Women's Health and Nutrition." Journal of the American Dietetic Association 1999.
OTHER
"Phosphorus in the Diet." <http//www.Healthcentral.com>. (June 2000).
"Serum Phosphorus." <http//www.Healthcentral.com>. (June 2000).
"Vitamin D." <http//www.Healthcentral.com>. (June 2000).
Joan Schonbeck
Phosphorus
Phosphorus
Description
Phosphorus (chemical symbol P) is a mineral discovered by the German alchemist Henig Brand in 1699. It plays an essential part in multiple biochemical reactions for both plants and animals and is essential to all life. Phosphorus is found in living things, in soil and rock, mostly as chemical compounds known as phosphates. Rock and soil phosphorus are mined extensively throughout the world, but especially in the Peoples' Republic of China and the United States.
Phosphorus extracted from rock is classified as either white, red, or black. White (also called yellow or common) phosphorus is a wax-like substance created by heating phosphate rock until it vaporizes and the condensation solidifies. One of this form's characteristics has given the English language the adjective phosphorescent, from white phosphorus's capacity to glow in the dark when exposed to air.
White phosphorus is highly toxic, causes burns if it comes in contact with skin, and is so combustible that it has to be stored underwater for safety. Red phosphorus is a rust-colored powder created by heating white phosphorus and exposing it to sunlight. It is not as combustible as the white form. Black phosphorus is made by heating white phosphorus under extremely high pressure until it resembles graphite.
In plants, phosphorus is necessary for photosynthesis to take place. In the human body, phosphorus works in tandem with another element, calcium, in much the same way that two other electrolyte components, sodium and potassium, do. Though phosphorus is found in every cell of the human body and accounts for 1% of the body's total weight, its primary function is working in conjunction with calcium to form teeth and bones.
Eighty-five percent of the phosphorus found in the body is located in these structures. In a delicately balanced chemical reaction, substances known as PTH (parathyroid hormone), calcitonin, and 25-dihydroxy vitamin D regulate the absorption of both calcium and phosphorus from the intestinal tract, thus making it available for the production of bones and teeth. If an excessive amount of phosphorus is absorbed, this will result in the phosphorus combining with all available calcium and preventing the calcium's efficient use in making and maintaining bones and teeth.
PTH balances the proportions of calcium and phosphorus in the body by increasing the release of calcium and phosphate from bone and the loss of phosphorus via the kidneys while limiting the excretion of calcium. PTH also increases the activity of the 25-dihydroxy vitamin D, which, in contrast, increases the absorption of both phosphorus and calcium from the intestinal tract.
General use
White phosphorus is a component of fertilizers, detergents and water softeners. It is also used in the manufacture of steel, plastics, insecticides, medical drugs, and animal feeds. Both white and red phosphorus are used in the making of safety matches and pesticides, including rat poison.
But the 15% of this element found in the blood stream and in other soft tissue also has a highly significant part to play in a variety of other body functions. Working with vitamin B, phosphorus is involved in the metabolism of fats and carbohydrates, in both the repair of damaged cells and tissues and the routine maintenance of healthy ones. Phosphorus is necessary for the regularity of the heartbeat, and aids in the contraction of all other muscles throughout the body. Phosphorus is needed for the functioning of the kidneys and plays a part in the conduction of impulses along the network that makes up the nervous system.
Preparations
According to the American Dietetic Association, phosphorus intake in the United States is generally above what is needed, and in recent years has actually increased. Therefore, under normal circumstances with normal food intake, there is seldom if ever a need to supplement intake of phosphorus. Persons suffering from eating disorders such as anorexia and bulimia can be deficient in phosphorus intake, as well as other nutrients. As the best source of phosphorus is in protein foods such as meat, eggs, and milk products, some vegetarians may also need to evaluate their intake of this element. Excess consumption of processed foods, and inadequate intake of whole foods, plus fertilizers and pesticides are some of the causes for excess phosphorus.
Beside high-protein foods, phosphorus is also found in decreasing quantities in whole grain breads and cereals, especially unprocessed ones, and in minute amounts in fruits and vegetables. The phosphorus present in whole grain breads and cereals, however, exists as a substance called phytin. Phytin combines with calcium to create a salt that the human body is incapable of absorbing, thus making unprocessed, unenriched grains a negligible source of phosphorus. But both commercially prepared cereals and breads may provide this element as they are frequently enriched with it. Phosphates can also be taken by mouth as a tablet.
Precautions
White phosphorus is poisonous. Red phosphorus is not. As noted, white phosphorus is a highly toxic, flammable substance capable of burning the skin if it makes contact, and of igniting at room temperature. It should be handled with extreme care. Accidental phosphorus poisoning can happen from both fertilizers and pesticides. Phosphates sometimes are leached into water systems through sewage and can drastically alter the chemical makeup of lakes and rivers. In sufficient quantities, they can lead to the death of nearly all forms of aquatic life.
A normal blood serum level of phosphorus is 2.4-4.1 mg per deciliter of blood. An abnormal serum phosphorus level should be evaluated by a physician.
Phosphorus levels higher than normal can indicate a diet that includes an excessive phosphorus intake, inadequate intake of calcium, or lack of PTH (parathyroid hormone) in the system. It can be related to bone metastasis associated with cancer, liver or kidney disease, or sarcoidosis.
Serum phosphorus levels that are below normal can be related to insufficient phosphorus or vitamin D in one's diet leading to rickets in children and osteomalacia in adults. Disorders of the parathyroid gland, causing it to secrete excessive quantities of PTH, or of the pancreas, causing it to secrete too much insulin, also affect blood levels of phosphorus. Diabetic ketoacidosis or too much calcium are other possible causes. Multiple endocrine neoplasia (MEN) is yet another condition that often is associated with lower than normal levels of phosphorus.
Side effects
Phosphorus preparations taken to supplement low phosphorus levels in the body can cause diarrhea.
KEY TERMS
Anorexia nervosa— A serious and sometimes fatal eating disorder characterized by intense fear of being fat and severe weight loss. It primarily affects teenage and young adult females. Sufferers have a distorted body image wherein they see themselves as being fat even when they are at normal weight or even emaciated.
Bulimia— An eating disorder characterized by bouts of gross overeating usually followed by self-induced vomiting.
Calcitonin— A hormone produced by the thyroid gland that controls the calcium level in the blood. It does this by slowing the rate that calcium is lost from bone.
Deciliter— A fluid measurement that is equal to one-tenth of a liter, or 100 cubic centimeters (27 fluid drams or teaspoonfuls).
Diabetic ketoacidosis— A potentially serious condition in which ketones become present in the blood stream because of the metabolism of fats burned in lieu of carbohydrates that would normally be used. This occurs because there is insufficient insulin available to cause carbohydrates to be used as fuel.
Electrolyte— Substances that split into ions, or electrically-charged particles, within the body to regulate many important bodily processes. Examples of electrolytes would be sodium, potassium, hydrogen, magnesium, calcium, bicarbonate, phosphates, and chlorides.
Multiple endocrine neoplasia— Tumor formation characterized by a progressive, abnormal multiplication of cells that are not necessarily malignant in any of the glands that secrete chemicals directly into the blood stream, such as the thyroid gland, adrenal glands, or ovaries.
Osteomalacia— Softening, weakening, and removal of the minerals from bone in adults caused by vitamin D deficiency.
Osteoporosis— Loss of formative protein tissue from bone, causing it to become brittle and easily fractured. It is considered to be a normal part of aging, but does have hormonal causes that make it much more common in women than men.
Sarcoidosis— A rare disease of currently unknown cause that occurs mostly in young adults. Inflammation occurs in the lymph nodes and other tissues throughout the body, usually including the lungs, liver, skin, and eyes.
Interactions
Antacids can decrease the absorption of phosphorus. Laxatives and enemas that contain the chemical compound sodium phosphate and excessive intake of vitamin D can increase phosphorus levels in the body. Administration of intravenous glucose solutions will cause phosphorus to combine with the glucose that is being absorbed by the cells.
Resources
BOOKS
Busch, Marianna A., Ph.D. Phosphorus, World Book. Chicago, IL: World Book, Inc., 1999.
Clayman, Charles B., M.D. The American Medical Association Home Medical Encyclopedia. New York: Random House, 1989.
PERIODICALS
Affenito, Sandra G., Ph R.D., and Jane Kerstetter, Ph R.D. "Position of the American Dietetic Association and Dietitians of Canada: Women's Health and Nutrition." Journal of the American Dietetic Association 1999.
OTHER
"Phosphorus in the Diet." 〈http://www.Healthcentral.com〉. (June 2000).
"Serum Phosphorus." 〈http://www.Healthcentral.com〉. (June 2000).
"Vitamin D." 〈http://www.Healthcentral.com〉. (June 2000).
Phosphorus
Phosphorus
Description
Phosphorus (chemical symbol P) is a mineral discovered by the German alchemist Henig Brand in 1699. It plays an essential part in multiple biochemical reactions for both plants and animals and is essential to all life. Phosphorus is found in living things, in soil and rock, mostly as chemical compounds known as phosphates. Rock and soil phosphorus are mined extensively throughout the world, but especially in the Peoples' Republic of China and the United States.
Phosphorus extracted from rock is classified as either white, red or black. White (also called yellow or common) phosphorus is a wax-like substance created by heating phosphate rock until it vaporizes and the condensation solidifies. One of this form's characteristics has given the English language the adjective phosphorescent, from white phosphorus's capacity to glow in the dark when exposed to air.
White phosphorus is highly toxic, causes burns if it comes in contact with skin, and is so combustible that it has to be stored underwater for safety. Red phosphorus is a rust-colored powder created by heating white phosphorus and exposing it to sunlight. It is not as combustible as the white form. Black phosphorus is made by heating white phosphorus under extremely high pressure until it resembles graphite.
In plants, phosphorus is necessary for photosynthesis to take place. In the human body, phosphorus works in tandem with another element, calcium , in much the same way that two other electrolyte components, sodium and potassium , do. Though phosphorus is found in every cell of the human body and accounts for 1% of the body's total weight, its primary function is working in conjunction with calcium to form teeth and bones.
Eighty-five percent of the phosphorus found in the body is located in these structures. In a delicately balanced chemical reaction, substances known as PTH (parathyroid hormone), Calcitonin, and 25-Dihydroxy vitamin D regulate the absorption of both calcium and phosphorus from the intestinal tract, thus making it available for the production of bones and teeth. If an excessive amount of phosphorus is absorbed, this will result in the phosphorus combining with all available calcium and preventing the calcium's efficient use in making and maintaining bones and teeth.
PTH balances the proportions of calcium and phosphorus in the body by increasing the release of calcium and phosphate from bone and the loss of phosphorus via the kidneys while limiting the excretion of calcium. PTH also increases the activity of the 25-Dihydroxy v25-Dihydroxy vitamin D , which, in contrast, increases the absorption of both phosphorus and calcium from the intestinal tract.
General use
White phosphorus is a component of fertilizers, detergents and water softeners. It is also used in the manufacture of steel, plastics, insecticides, medical drugs, and animal feeds. Both white and red phosphorus are used in the making of safety matches and pesticides, including rat poison.
But the 15% of this element found in the blood stream and in other soft tissue also has a highly significant part to play in a variety of other body functions. Working with Vitamin B, phosphorus is involved in the metabolism of fats and carbohydrates, in both the repair of damaged cells and tissues and the routine maintenance of healthy ones. Phosphorus is necessary for the regularity of the heartbeat, and aids in the contraction of all other muscles throughout the body. Phosphorus is needed for the functioning of the kidneys and plays a part in the conduction of impulses along the network that makes up the nervous system.
Preparations
According to the American Dietetic Association, phosphorus intake in the United States is generally above what is needed, and in recent years has actually increased. Therefore, under normal circumstances with normal food intake, there is seldom if ever a need to supplement intake of phosphorus. Persons suffering from eating disorders such as anorexia and bulimia can be deficient in phosphorus intake as well as other nutrients. As the best source of phosphorus is in protein foods such as meat, eggs and milk products, some vegetarians may also need to evaluate their intake of this element. Excess consumption of processed foods, and inadequate intake of whole foods, plus fertilizers and pesticides are some of the causes for excess phosphorus.
Beside high-protein foods, phosphorus is also found in decreasing quantities in whole grain breads and cereals, especially unprocessed ones, and in minute amounts in fruits and vegetables. The phosphorus present in whole grain breads and cereals, however, exists as a substance called phytin. Phytin combines with calcium to create a salt that the human body is incapable of absorbing, thus making unprocessed, unenriched grains a negligible source of phosphorus. But both commercially prepared cereals and breads may provide this element as they are frequently enriched with it. Phosphates can also be taken by mouth as a tablet.
Precautions
White phosphorus is poisonous. Red phosphorus is not. As noted, white phosphorus is a highly toxic, flammable substance capable of burning the skin if it makes contact, and of igniting at room temperature. It should be handled with extreme care. Accidental phosphorus poisoning can happen from both fertilizers and pesticides. Phosphates sometimes are leached into water systems through sewage and can drastically alter the chemical makeup of lakes and rivers. In sufficient quantities, they can lead to the death of nearly all forms of aquatic life.
A normal blood serum level of phosphorus is 2.4-4.1 mg per deciliter of blood. An abnormal serum phosphorus level should be evaluated by a physician.
Phosphorus levels higher than normal can indicate a diet that includes an excessive phosphorus intake, inadequate intake of calcium, or lack of PTH (parathyroid hormone) in the system. It can be related to bone metastasis associated with cancer , liver or kidney disease, or sarcoidosis.
Serum phosphorus levels that are below normal can be related to insufficient phosphorus or vitamin D in one's diet leading to rickets in children and osteomalacia in adults. Disorders of the parathyroid gland, causing it to secrete excessive quantities of PTH, or of the pancreas, causing it to secrete too much insulin, also affect blood levels of phosphorus. Diabetic ketoacidosis or too much calcium are other possible causes. Multiple endocrine neoplasia (MEN) is yet another condition that often is associated with lower than normal levels of phosphorus.
Side effects
Phosphorus preparations taken to supplement low phosphorus levels in the body can cause diarrhea .
Interactions
Antacids can decrease the absorption of phosphorus. Laxatives and enemas that contain the chemical compound sodium phosphate and excessive intake of vitamin D can increase phosphorus levels in the body. Administration of intravenous glucose solutions will cause phosphorus to combine with the glucose that is being absorbed by the cells.
Resources
BOOKS
Busch, Marianna A., Ph.D. Phosphorus, World Book. Chicago, IL: World Book, Inc., 1999.
Clayman, Charles B., MD. The American Medical Association Home Medical Encyclopedia. New York: Random House, 1989.
PERIODICALS
Affenito, Sandra G., pH, RD, and Jane Kerstetter, pH, RD. "Position of the American Dietetic Association and Dietitians of Canada: Women's Health and Nutrition." Journal of the American Dietetic Association 1999.
OTHER
"Phosphorus in the Diet." http//www.Healthcentral.com. (June 2000).
"Serum Phosphorus." http//www.Healthcentral.com. (June 2000).
"Vitamin D." http//www.Healthcentral.com. (June 2000).
Joan Schonbeck
Phosphorus
Phosphorus
melting point: 44.1°C
boiling point: 280°C
density: 1.82 g/cm 3
most common ions: PH 4+, P 3−, H 2PO 3−, PO 43−
The element phosphorus is essential to living organisms. It is part of the backbone of DNA (deoxyribonucleic acid), the carrier and transmitter of genetic information in cells. The element and its compounds have many commercial applications.
Phosphorus was first isolated by the alchemist Hennig Brand of Hamburg around 1670. He prepared white phosphorus, one of two common forms (allotropes) of the element, by evaporating human urine and strongly heating the residual solids. White phosphorus distilled and was collected under water.
The two common forms of phosphorus are white, which is made up of P4 molecules, containing four atoms of phosphorus arranged in a regular tetrahedral formation, and red, which is a noncrystalline polymer. White phosphorus glows in the dark and bursts into flame in air. Red phosphorus does not react rapidly with air.
Phosphorus makes up about 0.12 percent of Earth's crust. It is extracted from minerals that contain phosphate (PO43−) groups. Large deposits of such minerals, of which the most important is fluorapatite, Ca5F(PO4)3, are found in the United States, Morocco, Russia, and Tunisia. At the present rate of extraction, the known deposits of phosphate rock would be sufficient to supply the world's demand for phosphorus for the next 1,000 years.
More than 90 percent of commercial phosphorus production is in the form of calcium salts of phosphoric acid, H3PO4, used as fertilizers. Other significant uses of phosphorus compounds are in the manufacture of matches (phosphorus sulfides), food products and beverages (purified phosphoric acid and its salts), detergents (sodium polyphosphates), plasticizers for polymers (esters of phosphoric acid), and pesticides (derivatives of phosphoric acid). Related to the phosphorus pesticides are nerve gases, poisonous compounds that rapidly attack the central nervous system, initially developed during World War II.
see also Deoxyribonucleic Acid (DNA); Fertilizer; Pesticides.
Harold Goldwhite
Bibliography
Greenwood, Norman N., and Earnshaw, A. (1984). Chemistry of the Elements. New York: Pergamon Press.
Weeks, Mary Elvira, and Leicester, Henry M. (1968). Discovery of the Elements, 7th edition. Easton, PA: Journal of Chemical Education.
phosphorus
Adult needs (about 1.3 g per day) are always met. The calcium to phosphate ratio of infant foods is, however, important. Phosphate deficiency is common in livestock and gives rise to osteomalacia (also known as sweeny or creeping sickness).
Phosphorus
Phosphorus
Phosphorus is a chemical element with the atomic number 15 and atomic weight 30.9738. Phosphorus forms the basis of a large number of compounds, by far the most environmentally important of which are phosphates. All plants and animals need phosphates for growth and function, and in many natural waters the production of algae and higher plants is limited by the low natural levels of phosphorus. As the amount of available phosphorus in an aquatic environment increases, plant and algal growth can increase dramatically leading to eutrophication . In the past, one of the major contributors to phosphorus pollution was household detergents containing phosphates. These substances have now been banned from these products. Other contributors to phosphorus pollution are sewage treatment plants and runoff from cattle feedlots. (Animal feces contain significant amounts of phosphorus.) Erosion of farmland treated with phosphorus fertilizers or animal manure also contributes to eutrophication and water pollution .
See also Phosphoric acid; Phosphorus removal.
Phosphorus
Phosphorus
An important chemical element, which has the atomic number 15 and atomic weight 30.9738. Phosphorus forms the basis of a large number of compounds, by far the most environmentally important of which are phosphates . All plants and animals need phosphates for growth and function, and in many natural waters the production of algae and higher plants is limited by the low natural levels of phosphorus. As the amount of available phosphorus in an aquatic environment increases, plant and algal growth can increase dramatically leading to eutrophication. In the past, one of the major contributors to phosphorus pollution was household detergents containing phosphates. These substances have now been banned from these products. Other contributors to phosphorus pollution are sewage treatment plants and runoff from cattle feedlots . (Animal feces contain significant amounts of phosphorus.) Erosion of farmland treated with phosphorus fertilizers or animal manure also contributes to eutrophication and water pollution .
See also Cultural eutrophication