Discovered in 1669 by Brand, who prepared it from urine. Phosphorus exists in four or more allotropic forms: white (or yellow), red, and black (or violet). White phosphorus has two modifications: alpha and beta with a transition temperature at –3.8°C. Never found free in nature, it is widely distributed in combination with minerals. Seventeen isotopes of phosphorus are recognized. Phosphate rock, which contains the mineral apatite, an impure tri-calcium phosphate, is an important source of the element. Large deposits are found in the U.S.S.R., in Morocco, and in Florida, Tennessee, Utah, Idaho, and elsewhere. Phosphorus in an essential ingredient of all cell protoplasm, nervous tissue, and bones. Ordinary phosphorus is a waxy white solid; when pure it is colorless and transparent. It is insoluble in water, but soluble in carbon disulfide. It takes fire spontaneously in air, burning to the pentoxide. It is very poisonous, 50 mg constituting an approximate fatal dose. Exposure to white phosphorus should not exceed 0.1 mg/m^3 (8-hour time-weighted average — 40-hour work week). White phosphorus should be kept under water, as it is dangerously reactive in air, and it should be handled with forceps, as contact with the skin may cause severe burns. When exposed to sunlight or when heated in its own vapor to 250°C, it is converted to the red variety, which does not phosphoresce in air as does the white variety. This form does not ignite spontaneously and it is not as dangerous as white phosphorus. It should, however, be handled with care as it does convert to the white form at some temperatures and it emits highly toxic fumes of the oxides of phosphorus when heated. The red modification is fairly stable, sublimes with a vapor pressure of 1 atm at 417°C,and is used in the manufacture of safety matches, pyrotechnics, pesticides, incendiary shells, smoke bombs, tracer bullets, etc. White phosphorus may be made by several methods. By one process, tri-calcium phosphate, the essential ingredient of phosphate rock, is heated in the presence of carbon and silica in an electric furnace or fuel-fired furnace. Elementary phosphorus is liberated as vapor and may be collected under water. If desired, the phosphorus vapor and carbon monoxide produced by the reaction can be oxidized at once in the presence of moisture to produce phosphoric acid, an important compound in making super-phosphate fertilizers. In recent years, concentrated phosphoric acids, which may contain as much as 70 to 75% P2O5 content, have become of great importance to agriculture and farm production. World-wide demand for fertilizers has caused record phosphate production. Phosphates are used in the production of special glasses, such as those used for sodium lamps. Bone-ash, calcium phosphate, is also used to produce fine chinaware and to produce mono-calcium phosphate used in baking powder. Phosphorus is also important in the production of steels, phosphor bronze, and many other products. Trisodium phosphate is important as a cleaning agent, as a water softener, and for preventing boiler scale and corrosion of pipes and boiler tubes. Organic compounds of phosphorus are important. Amorphous (red) phosphorus costs about $60/kg (99.5%). 1

• "is essential for plant growth" 2
• "The largest use of phosphorus is in fertilizers. Phosphorus is an essential nutrient, and nature's phosphorus cycle is very slow owing to the low solubility of most natural phosphates. Phosphate fertilizers are therefore essential." 3
• "Phosphorus occurs as rock phosphate [Ca₅(PO₄)₃OH]. Phosphates are essential to all living things and are therefore important constituents of commercial fertilizers." 4
• "Until the early part of this [20th] century, white phosphorus was used in matches. Red phosphorus...is the active ingredient of the striking surface of a safety match, which has a head containing potassium chlorate, KClO₃. When the match is struck against the red phosphorus surface, a reaction of the phosphorus and potassium chlorate causes the match to ignite...Most of the white phosphorus produced is converted to phosphoric acid, H₃PO₄." 5
• "Consider what happens when we dope pure silicon with phosphorus, an element having five instead of the four valence electrons of silicon. A few of the silicon atoms in the structure are replaced by phosphorus atoms. Because each phosphorus atom has five valence electrons, one electron is left over after four bonds are formed to silicon atoms. The extra electron is free to conduct an electric current, and the phosphorus-doped silicon becomes a conductor. It is called an n-type semiconductor, because the current is carried by negative charges (electrons)." 6

Form:7 red
Melting Point:7* 
Boiling Point:7* 
Sublimation Point:7 431 °C = 704.15 K = 807.8 °F
Triple Point:7 590 °C = 863.15 K = 1094 °F
Critical Point:7 721 °C = 994.15 K = 1329.8 °F 7
Form:7 white
Melting Point:7*  44.15 °C = 317.3 K = 111.47 °F
Boiling Point:7* 280.5 °C = 553.65 K = 536.9 °F
Sublimation Point:7 
Triple Point:7 
Critical Point:7 721 °C = 994.15 K = 1329.8 °F 7
Form:7 black
Melting Point:7*  610 °C = 883.15 K = 1130 °F
Boiling Point:7* 
Sublimation Point:7 
Triple Point:7 
Critical Point:7 
Density:8  1.823 (white)/2.16 (red) g/cm3

* - at 1 atm

Electron Configuration

Bonding

Thermochemistry

Isotopes

Earth - Source Compounds: phosphates 18
Earth - Seawater: 0.06 mg/L 19
Earth -  Crust:  1050 mg/kg = 0.105% 19
Earth -  Lithosphere:  0.11% 20
Earth -  Total:  1920 ppm 21
Mercury -  Total:  390 ppm 21
Venus -  Total:  1860 ppm 21
Chondrites - Total: 5300 (relative to 106 atoms of Si) 22
Human Body - Total: 1.1% 23

Material Safety Data Sheet - ACI Alloys, Inc.

External Links:

Magazines:
(1) Tweed, Katherine. Sewage's Cash Crop. Scientific American, November 2009, pp 28.
(2) Vaccari, David A. Phosphorus: A Looming Crisis. Scientific American, June 2009, pp 54-59.

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:22.
(2) - Zumdahl, Steven S. Chemistry, 4th ed.: Houghton Mifflin: Boston, 1997; p 915.
(3) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 965.
(4) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 7.
(5) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 345.
(6) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 394.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(9) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(13) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(14) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(15) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(16) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(17) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(18) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(19) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(20) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 964.
(21) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(22) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.
(23) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 7:17.