ARSÉNICO

Introducción

Número atómico: 33
Grupo: 15 or V A
Peso atomico: 74.9216
Período: 4
Número CAS: 7440-38-2

Clasificación

chalcogen
halógeno
Gas noble
Lantanoides
Actinoides
Elemento de tierras raras
Platino Metal Group
transuranium
No hay isótopos estables
Sólido
Líquido
Gas
Sólido (Predicho)

Descripción • Usos / Función

Elemental arsenic occurs in twosolid modifications: yellow, and gray or metallic, with specific gravities of 1.97, and 5.73, respectively. Gray arsenic, the ordinary stable form, hasa m.p. of 817°C (28 atm) and sublimes at 614°C. Several other allotropic forms of arsenic are reported in the literature. It is believed that AlbertusMagnus obtained the element in 1250 A.D. In 1649 Schroeder published two methods of preparing the element. It is found native, in the sulfides realgarand orpiment, as arsenides and sulfarsenides of heavy metals, as the oxide, and as arsenates. Mispickel, arsenopyrite, (FeSAs) is the most commonmineral, from which on heating the arsenic sublimes leaving ferrous sulfide. The element is a steel gray, very brittle, crystalline, semimetallic solid;it tarnishes in air, and when heated is rapidly oxidized to arsenous oxide (As2O3) with the odor of garlic. Arsenic and its compounds are poisonous.These values, however, are being studied, and may be lowered. Arsenic is also used in bronzing, pyrotechny, and for hardening and improving thesphericity of shot. The most important compounds are white arsenic (As2O3), the sulfide, Paris green 3Cu(AsO2)2 · Cu(C2H3O2)2, calcium arsenate,and lead arsenate; the last three have been used as agricultural insecticides and poisons. Marsh’s test makes use of the formation and readydecomposition of arsine (AsH3). Arsenic is available in high-purity form. It is finding increasing uses as a doping agent in solid-state devices suchas transistors. Gallium arsenide is used as a laser material to convert electricity directly into coherent light. Natural arsenic is made of one isotope 75As.Twenty-five other radioactive isotopes and isomers are known. Arsenic (99%) costs about $175/kg. Purified arsenic (99.9995%) costs about $2/gm. 1

• "amino acid metabolism" 2
• "Farmers using arsenic as an insecticide often suffer from skin and lung cancers." 3

Propiedades físicas

Punto de fusion:4
Punto de ebullición:4
Punto de sublimación:4 603 °C = 876.15 K = 1117.4 °F
Triple punto:4 817 °C = 1090.15 K = 1502.6 °F at 3.70 MPa
Punto crítico:4 1400 °C = 1673.15 K = 2552 °F 4
Densidad:5  5.75 g/cm3

* - at 1 atm

Configuración electronica

Configuración electronica: [Ar] 4s2 3d10 4p3
Bloquear: p
Ocupado más alto nivel de energía: 4
Electrones de valencia: 5

Números cuánticos:

n = 4
ℓ = 1
m = 1
ms = +½

Vinculación

electronegatividad (escala de Pauling):6 2.18
Electropositivity (escala de Pauling): 1.82
Afinidad electronica:7 0.814 eV
estados de oxidación: ±3,+5
Función del trabajo:8 3.75 eV = 6.0075E-19 J

potencial de ionización   eV 9  kJ/mol  
1 9.7886    944.5
2 18.633    1797.8
potencial de ionización   eV 9  kJ/mol  
3 28.351    2735.5
4 50.13    4836.8
potencial de ionización   eV 9  kJ/mol  
5 62.63    6042.9
6 127.6    12311.5

termoquímica

Calor especifico: 0.329 J/g°C 10 = 24.649 J/mol°C = 0.079 cal/g°C = 5.891 cal/mol°C
Conductividad térmica: 50 (W/m)/K, 27°C 11
Calor de fusión: 
Calor de vaporización: 34.76 kJ/mol 12 = 464.0 J/g
Estado de la materia Entalpía de formación (ΔHf°)13 entropía (S°)13 Energía libre de Gibbs (ΔGf°)13
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s alpha-gray) 0 0 8.4 35.1456 0 0

isótopos

nucleido Masa 14 Media vida 14 spin nuclear 14 Energía de unión
60As 59.99313(64)# 5+# 464.98 MeV
61As 60.98062(64)# 3/2-# 485.16 MeV
62As 61.97320(32)# 1+# 499.75 MeV
63As 62.96369(54)# (3/2-)# 517.14 MeV
64As 63.95757(38)# 40(30) ms [18(+43-7) ms] 0+# 530.80 MeV
65As 64.94956(32)# 170(30) ms 3/2-# 546.32 MeV
66As 65.94471(73) 95.77(23) ms (0+) 559.05 MeV
67As 66.93919(11) 42.5(12) s (5/2-) 571.78 MeV
68As 67.93677(5) 151.6(8) s 3+ 582.65 MeV
69As 68.93227(3) 15.2(2) min 5/2- 594.44 MeV
70As 69.93092(5) 52.6(3) min 4(+#) 604.38 MeV
71As 70.927112(5) 65.28(15) h 5/2- 615.24 MeV
72As 71.926752(5) 26.0(1) h 2- 624.25 MeV
73As 72.923825(4) 80.30(6) d 3/2- 635.11 MeV
74As 73.9239287(25) 17.77(2) d 2- 643.18 MeV
75As 74.9215965(20) ESTABLE 3/2- 653.12 MeV
76As 75.922394(2) 1.0942(7) d 2- 660.26 MeV
77As 76.9206473(25) 38.83(5) h 3/2- 670.19 MeV
78As 77.921827(11) 90.7(2) min 2- 677.33 MeV
79As 78.920948(6) 9.01(15) min 3/2- 686.34 MeV
80As 79.922534(25) 15.2(2) s 1+ 692.54 MeV
81As 80.922132(6) 33.3(8) s 3/2- 700.61 MeV
82As 81.92450(21) 19.1(5) s (1+) 706.82 MeV
83As 82.92498(24) 13.4(3) s 3/2-# 714.89 MeV
84As 83.92906(32)# 4.02(3) s (3)(+#) 718.31 MeV
85As 84.93202(21)# 2.021(10) s (3/2-)# 723.59 MeV
86As 85.93650(32)# 0.945(8) s 727.93 MeV
87As 86.93990(32)# 0.56(8) s 3/2-# 733.21 MeV
88As 87.94494(54)# 300# ms [>300 ns] 736.62 MeV
89As 88.94939(54)# 200# ms [>300 ns] 3/2-# 740.04 MeV
90As 89.95550(86)# 80# ms [>300 ns] 742.52 MeV
91As 90.96043(97)# 50# ms [>300 ns] 3/2-# 745.93 MeV
92As 91.96680(97)# 30# ms [>300 ns] 748.41 MeV
Los valores marcados con # no son puramente derivan de los datos experimentales, pero al menos en parte, de las tendencias sistemáticas. Hace girar con débiles argumentos de asignación se incluyen entre paréntesis. 14

reacciones

Abundancia

Tierra - Los compuestos de origen: sulfides 17
Tierra - Agua de mar: 0.0037 mg/L 18
Tierra -  Corteza:  1.8 mg/kg = 0.00018% 18
Tierra -  Total:  3.2 ppm 19
Planeta mercurio) -  Total:  6.4 ppm 19
Venus -  Total:  3.1 ppm 19
condritas - Total: 4.6 (relative to 106 atoms of Si) 20

Compuestos

Información de seguridad


Ficha de datos de seguridad de materiales - ACI Alloys, Inc.

Para más información

Enlaces externos:

Fuentes

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:4.
(2) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 926.
(3) - Neighbors, Marianne and Tannehill-Jones, Ruth. Human Diseases, 2nd ed.; Thomson Delmar Learning: Clifton Park, NY, 2006; p 32.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(6) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(8) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(13) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(14) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(15) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(16) - Halka, Monica and Nordstrom, Brian. Metals & Metalloids; Infobase Publishing: New York, NY, 2011; pg. 97.
(17) - Atkins, Jones, and Laverman. Chemical Principles 6th ed.; W.H. Freeman and Company: New York, NY, 2013; p F94.
(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) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(21) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.