Phosphorus

Phosphorus occurs in three or more allotropic forms, white (or yellow), red, and black (or violet).   White phosphorus will glow (phosphorescence) as it turns into the more stable red phosphorus.   White phosphorus is used in the manufacture of safety matches, pyrotechnics, pesticides, incendiary ammunition, smoke bombs, and tracer bullets.   The separated vaporized phosphorus and associated carbon monoxide (CO) can be oxidized   immediately by the moisture in the air to produce phosphoric acid, an important compound in super-phosphate fertilizers.   Phosphates are used in specialized glass manufacture, such as sodium lamps.   "Bone ash", calcium phosphate, is used in fine chinaware production and mono-calcium phosphate is used in baking powder.   Phosphorus is used in steel, phosphor bronze, and other metals.   Trisodium phosphate is used as a detergent, water softener, and boiler scale and corrosion preventative. ^{Lide 4-21}

Phosphorus is essential to life.   It is an essential element in all cells, bones, teeth, nerves, and enzymes.   As part of the energy molecule ATP, adenosine triphosphate, it helps the release of carbohydrate energy.   Sources: meat, poultry, fish, eggs, dried peas and beans, milk and milk products, processed foods and drinks.   Deficiencies are uncommon, but when occurring, they result in weakness, malaise, appetite loss, and bone pain. ^{Brody 184}   Excessive phosphorus from fertilizers and detergents that leach into freshwater lakes and rivers limit acquatic animal life by causing excessive plant and algae growth and death, during which decomposing bacteria use up the oxygen gas dissolved in the water, making it unavailable to acquatic animals. This process is called eutrophication.

In plants, phosphorus is necessary for seed germination, photosynthesis, protein formation, flower and fruit formation, and almost all aspects of growth and metabolism.   A low soil pH (< 4, acidic) results in phosphate being chemically locked up in the soil.   A deficiency results in purple stems and leaves, retarded growth, poor yield of fruit and flowers, and possibly a premature drop of fruits and flowers.   Because phosphorus is taken up by the plant roots, a deficiency is common, thus requiring a fertilizer application for replacement.   Phosphorus must be applied near the plant roots in order for the plant to use it.   Large applications of phosphorus without adequate levels of zinc can cause a zinc deficiency. ^{Morgan n.p.}

Phosphorus was discovered in 1669 by Hennig Brand, a German chemist, who prepared it from urine.   It was the first element discovered by a known person.   Phosphorus occurs commonly in phosphate rock, which contains the mineral apatite.   It can be isolated by heating tri-calcium phosphate, the main ingredient of phosphate rock, in the presence of carbon and silica in an electric fuel-fired furnace.   The pure phosphorus becomes a vapor that is collected under water because it is highly reactive. ^{Lide 4-21}