FÓSFORO

Introdução

Número atômico: 15
Grupo: 15 or V A
Peso atômico: 30.973761
Período: 3
Número CAS: 7723-14-0

Classificação

Calcogênio
halogênio
Gás nobre
Lantanóides
Actinóide
Terra-rara
Platinum Metal Group
Transuranium
Não Isótopos Estáveis
Sólido
Líquido
Gás
Sólido (previsto)

Descrição • Usos / Função

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

Propriedades físicas

Form:7 red
Ponto de fusão:7
Ponto de ebulição:7
Ponto de sublimação:7 431 °C = 704.15 K = 807.8 °F
Ponto Triplo:7 590 °C = 863.15 K = 1094 °F
Ponto crítico:7 721 °C = 994.15 K = 1329.8 °F 7
Form:7 white
Ponto de fusão:7*  44.15 °C = 317.3 K = 111.47 °F
Ponto de ebulição:7* 280.5 °C = 553.65 K = 536.9 °F
Ponto de sublimação:7 
Ponto Triplo:7 
Ponto crítico:7 721 °C = 994.15 K = 1329.8 °F 7
Form:7 black
Ponto de fusão:7*  610 °C = 883.15 K = 1130 °F
Ponto de ebulição:7
Ponto de sublimação:7 
Ponto Triplo:7 
Ponto crítico:7 
Densidade:8  1.823 (white)/2.16 (red) g/cm3

* - at 1 atm

Configuração Electron

Configuração Electron: [Ne] 3s2 3p3
Quadra: p
Mais alto nível de energia Ocupado: 3
Elétrons de valência: 5

Números quânticos:

n = 3
ℓ = 1
m = 1
ms = +½

Colagem

Eletronegatividade (escala Pauling):9 2.19
Electropositivity (escala Pauling): 1.81
Electron Affinity:10 0.7465 eV
oxidação Unidos: -3

potencial de ionização   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
potencial de ionização   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
potencial de ionização   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

Termoquímica

Calor específico: 0.769 J/g°C 12 = 23.819 J/mol°C = 0.184 cal/g°C = 5.693 cal/mol°C
Condutividade térmica: 0.235 (W/m)/K, 27°C 13
Calor de fusão: 0.657 kJ/mol 14 = 21.2 J/g
Calor da vaporização: 12.129 kJ/mol 15 = 391.6 J/g
Estado da matéria Entalpia de formação (ΔHf°)16 entropia (S°)16 Gibbs Energia Livre (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

isótopos

nuclide Massa 17 Meia vida 17 spin nuclear 17 Energia de ligação
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) ESTÁVEL 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
Os valores marcados # não são puramente derivado a partir de dados experimentais, mas, pelo menos, parcialmente a partir de tendências sistemáticas. Gira com argumentos de atribuição fracos estão entre parênteses. 17

Abundância

Terra - Os compostos de origem: phosphates 18
Terra - A água do mar: 0.06 mg/L 19
Terra -  crosta:  1050 mg/kg = 0.105% 19
Terra -  litosfera:  0.11% 20
Terra -  Total:  1920 ppm 21
Planeta Mercúrio) -  Total:  390 ppm 21
Vênus -  Total:  1860 ppm 21
condritos - Total: 5300 (relative to 106 atoms of Si) 22
Corpo humano - Total: 1.1% 23

compostos

Informação de Segurança


Material Safety Data Sheet - ACI Alloys, Inc.

Para maiores informações

Links externos:

revistas:
(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.

Fontes

(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.