Introduction
Group: 15 or V A
Atomic Weight: 30.973761
Period: 3
CAS Number: 7723-14-0
Classification
No Stable Isotopes
Solid
Liquid
Gas
Solid (Predicted)
Description • Uses/Function
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
Physical Properties
Form:7 red
Electron Configuration: [Ne] 3s2 3p3
n = 3
Electronegativity (Pauling scale):9 2.19
Specific Heat: 0.769 J/g°C 12 = 23.819 J/mol°C = 0.184 cal/g°C = 5.693 cal/mol°C
Earth - Source Compounds: phosphates 18
External Links:
Magazines:
(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:22.
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
Block: p
Highest Occupied Energy Level: 3
Valence Electrons: 5
Quantum Numbers:
ℓ = 1
mℓ = 1
ms = +½
Bonding
Electropositivity (Pauling scale): 1.81
Electron Affinity:10 0.7465 eV
Oxidation States: -3
Ionization Potential
eV 11
kJ/mol
1
10.48669
1011.8
2
19.7694
1907.5
3
30.2027
2914.1
4
51.4439
4963.6
5
65.0251
6274.0
Ionization Potential
eV 11
kJ/mol
6
220.421
21267.4
7
263.57
25430.6
8
309.6
29871.9
9
372.13
35905.1
10
424.4
40948.4
Ionization Potential
eV 11
kJ/mol
11
479.46
46260.8
12
560.8
54109.0
13
611.74
59023.9
14
2816.91
271790.4
15
3069.842
296194.7
Thermochemistry
Thermal Conductivity: 0.235 (W/m)/K, 27°C 13
Heat of Fusion: 0.657 kJ/mol 14 = 21.2 J/g
Heat of Vaporization: 12.129 kJ/mol 15 = 391.6 J/g
State of Matter
Enthalpy of Formation (ΔHf°)16
Entropy (S°)16
Gibbs Free Energy (ΔGf°)16
(kcal/mol)
(kJ/mol)
(cal/K)
(J/K)
(kcal/mol)
(kJ/mol)
(s red V)
0
0
5.45
22.8028
0
0
(l red V)
4.32
18.07488
10.25
42.886
2.89
12.09176
(g red V)
79.80
333.8832
38.98
163.09232
69.80
292.0432
(s alpha white)
4.17
17.44728
9.82
41.08688
2.87
12.00808
Isotopes
Nuclide
Mass 17
Half-Life 17
Nuclear Spin 17
Binding Energy
24P
24.03435(54)#
(1+)#
150.31 MeV
25P
25.02026(21)#
<30 ns
(1/2+)#
171.42 MeV
26P
26.01178(21)#
43.7(6) ms
(3+)
187.87 MeV
27P
26.999230(28)
260(80) ms
1/2+
207.12 MeV
28P
27.992315(4)
270.3(5) ms
3+
221.71 MeV
29P
28.9818006(6)
4.142(15) s
1/2+
240.03 MeV
30P
29.9783138(3)
2.498(4) min
1+
250.90 MeV
31P
30.97376163(20)
STABLE
1/2+
263.63 MeV
32P
31.97390727(20)
14.263(3) d
1+
271.70 MeV
33P
32.9717255(12)
25.34(12) d
1/2+
281.63 MeV
34P
33.973636(5)
12.43(8) s
1+
287.84 MeV
35P
34.9733141(20)
47.3(7) s
1/2+
295.91 MeV
36P
35.978260(14)
5.6(3) s
4-#
299.32 MeV
37P
36.97961(4)
2.31(13) s
1/2+#
306.46 MeV
38P
37.98416(11)
0.64(14) s
309.88 MeV
39P
38.98618(11)
190(50) ms
1/2+#
316.09 MeV
40P
39.99130(15)
153(8) ms
(2-,3-)
319.50 MeV
41P
40.99434(23)
100(5) ms
1/2+#
324.78 MeV
42P
42.00101(48)
48.5(15) ms
326.33 MeV
43P
43.00619(104)
36.5(15) ms
1/2+#
329.74 MeV
44P
44.01299(75)#
18.5(25) ms
332.22 MeV
45P
45.01922(86)#
8# ms [>200 ns]
1/2+#
333.78 MeV
46P
46.02738(97)#
4# ms [>200 ns]
334.39 MeV
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses. 17
Abundance
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
Compounds
arsenic diphosphide
arsenic monophosphide
arsenic phosphide
arsenic triphosphide
boron phosphide
cadmium phosphide
calcium phosphide
gallium(III) phosphide; gallium phosphide
hafnium phosphide
indium(III) phosphide
lithium phosphide
magnesium phosphide
nickel phosphide
phosphorus decaoxide
phosphorus heptasulfide
phosphorus hexoxide
phosphorus nonasulfide
phosphorus oxybromide
phosphorus oxychloride
phosphorus pentabromide
phosphorus pentachloride*; phosphorus(V) chloride; pentachlorophosphorane
phosphorus pentafluoride
phosphorus pentasulfide; tetraphosphorus decasulfide
phosphorus pentoxide
phosphorus tetrabromide
phosphorus tetrachloride
phosphorus tetrafluoride
phosphorus tetrahydride
phosphorus tetraiodide
phosphorus thiochloride
phosphorus tribromide
phosphorus trichloride
phosphorus trifluoride
phosphorus trihydride; phosphane; phosphine
phosphorus triiodide
phosphorus trioxide
phosphorus triselenide
phosphorus trisulfide
potassium phosphide
strontium phosphide
titanium(III) phosphide
yttrium(III) phosphide
zinc phosphide
zirconium(IV) phosphide
Safety Information
Material Safety Data Sheet - ACI Alloys, Inc.
For More Information
American Elements
Chemical & Engineering News
Chemical Elements
ChemGlobe
Chemicool
Environmental Chemistry
(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.
Sources
(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.