MAGNESIO

Introducción

Número atómico: 12
Grupo: 2 or II A
Peso atomico: 24.305
Período: 3
Número CAS: 7439-95-4

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

Compounds of magnesium have long been known. Black recognized magnesium as an element in 1755. It was isolated by Davy in 1808, and prepared in coherent form by Bussy in 1831. Magnesium is the eighth most abundant element in the earth’s crust. It does not occur uncombined, but is found in large deposits in the form of magnesite, dolomite, and other minerals. The metal is now principally obtained in the U.S. by electrolysis of fused magnesium chloride derived from brines, wells, and sea water. Magnesium is a light, silvery-white, and fairly tough metal. It tarnishes slightly in air, and finely divided magnesium readily ignites upon heating in air and burns with a dazzling white flame. It is used in flashlight photography, flares, and pyrotechnics, including incendiary bombs. It is one third lighter than aluminium, and in alloys is essential for airplane and missile contruction. The metal improves the mechanical, fabrication, and welding characteristics of aluminum when used as an alloying agent. Magnesium is used in producing nodular graphite in cast iron,and is used as an additive to conventional propellants. It is also used as a reducing agent in the production of pure uranium and other metals from their salts. The hydroxide (milk of magnesia), chloride, sulfate (Epsom salts), and citrate are used in medicine. Dead-burned magnesite is employed for refractory purposes such as brick and liners in furnaces and converters. Organic magnesium compounds (Grignard’s reagents) are important. Magnesium is an important element in both plant and animal life. Chlorophylls are magnesium-centered porphyrins. The adult daily requirement of magnesium is about 300 mg/day, but this is affected by various factors. Great care should be taken in handling magnesium metal, especially in the finely divided state, as serious fires can occur. Water should not be used on burning magnesium or on magnesium fires. Natural magnesium contains three isotopes. Twelve other isotopes are recognized. Magnesium metal costs about $170/kg (99.99%). 1

• "(as the Mg2+ ion) plays a vital role in metabolism and muscle functions" 2
• "commonly used to produce the bright light for photographic flash units" 3
• "is a useful structural material, especially if alloyed with aluminum" 4
• "alloys having more magnesium than aluminum are used when a high strength-to-weight ratio is needed and when corrosion resistance is important, such as in aircraft and automotive parts and in lightweight tools" 5
• "It has been suggested that magnesium, an essential component in chlorophyll, is removed from pine needles by the combined effects of ozone and acids...Another harmful effect of acid rain may be that it leaches essential metal ions such as Ca2+ and Mg2+ from soil as soluble salts." 6
• "The tires on the Hummer vehicles used in the Gulf War were made blowout-proof by strong, lightweight magnesium inserts....used in photographic flash accessories and fireworks. It is very lightweight and is currently used in many alloys for building materials." 7
• "used in lightweight alloys...Mg compounds find applications in the pharmaceutical and chemical process industries." 8

Propiedades físicas

Punto de fusion:9*  650 °C = 923.15 K = 1202 °F
Punto de ebullición:9* 1090 °C = 1363.15 K = 1994 °F
Punto de sublimación:9 
Triple punto:9 
Punto crítico:9 
Densidad:10  1.74 g/cm3

* - at 1 atm

Configuración electronica

Configuración electronica: [Ne] 3s2
Bloquear: s
Ocupado más alto nivel de energía: 3
Electrones de valencia: 2

Números cuánticos:

n = 3
ℓ = 0
m = 0
ms = -½

Vinculación

electronegatividad (escala de Pauling):11 1.31
Electropositivity (escala de Pauling): 2.69
Afinidad electronica:12 not stable eV
estados de oxidación: +2
Función del trabajo:13 3.66 eV = 5.86332E-19 J

potencial de ionización   eV 14  kJ/mol  
1 7.64624    737.7
2 15.03528    1450.7
3 80.1437    7732.7
4 109.2655    10542.5
potencial de ionización   eV 14  kJ/mol  
5 141.27    13630.5
6 186.76    18019.6
7 225.02    21711.1
8 265.96    25661.2
potencial de ionización   eV 14  kJ/mol  
9 328.06    31653.0
10 367.5    35458.4
11 1761.805    169988.3
12 1962.665    189368.3

termoquímica

Calor especifico: 1.023 J/g°C 15 = 24.864 J/mol°C = 0.245 cal/g°C = 5.943 cal/mol°C
Conductividad térmica: 156 (W/m)/K, 27°C 16
Calor de fusión: 8.954 kJ/mol 17 = 368.4 J/g
Calor de vaporización: 127.4 kJ/mol 18 = 5241.7 J/g
Estado de la materia Entalpía de formación (ΔHf°)19 entropía (S°)19 Energía libre de Gibbs (ΔGf°)19
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s) 0 0 7.814 32.693776 0 0
(ℓ) 2.16 9.03744 10.16 42.50944 1.46 6.10864
(g) 35.28 147.61152 35.50 148.532 27.03 113.09352

isótopos

nucleido Masa 20 Media vida 20 spin nuclear 20 Energía de unión
19Mg 19.03547(27) 1/2-# 111.36 MeV
20Mg 20.018863(29) 90.8(24) ms 0+ 135.27 MeV
21Mg 21.011713(18) 122(2) ms (5/2,3/2)+ 149.86 MeV
22Mg 21.9995738(14) 3.8755(12) s 0+ 169.11 MeV
23Mg 22.9941237(14) 11.317(11) s 3/2+ 181.84 MeV
24Mg 23.985041700(14) ESTABLE 0+ 198.30 MeV
25Mg 24.98583692(3) ESTABLE 5/2+ 206.37 MeV
26Mg 25.982592929(30) ESTABLE 0+ 217.23 MeV
27Mg 26.98434059(5) 9.458(12) min 1/2+ 223.44 MeV
28Mg 27.9838768(22) 20.915(9) h 0+ 232.44 MeV
29Mg 28.988600(15) 1.30(12) s 3/2+ 235.86 MeV
30Mg 29.990434(9) 335(17) ms 0+ 242.07 MeV
31Mg 30.996546(13) 230(20) ms 3/2+ 244.55 MeV
32Mg 31.998975(19) 86(5) ms 0+ 250.76 MeV
33Mg 33.005254(21) 90.5(16) ms 7/2-# 252.31 MeV
34Mg 34.00946(25) 20(10) ms 0+ 256.65 MeV
35Mg 35.01734(43)# 70(40) ms (7/2-)# 257.27 MeV
36Mg 36.02300(54)# 3.9(13) ms 0+ 259.75 MeV
37Mg 37.03140(97)# 40# ms [>260 ns] 7/2-# 260.37 MeV
38Mg 38.03757(54)# 1# ms [>260 ns] 0+ 262.86 MeV
39Mg 39.04677(55)# <260 ns 7/2-# 262.54 MeV
40Mg 40.05393(97)# 1# ms 0+ 264.10 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. 20

reacciones

Abundancia

Tierra - Los compuestos de origen: carbonates/sulfates 26
Tierra - Agua de mar: 1290 mg/L 27
Tierra -  Corteza:  23300 mg/kg = 2.33% 27
Tierra -  Manto:  16.6% 28
Tierra -  litosfera:  2.76% 29
Tierra -  Hidrosfera:  0.13% 29
Tierra -  Total:  13.90% 30
Planeta mercurio) -  Total:  6.50% 30
Venus -  Total:  14.54% 30
Universo -  Total:  0.06% 28
condritas - Total: 9.4×105 (relative to 106 atoms of Si) 31
Cuerpo humano - Total: 0.027% 32

Compuestos

Precios





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 4:18.
(2) - Zumdahl, Steven S. Chemistry, 4th ed.; Houghton Mifflin: Boston, 1997; p 883.
(3) - Zumdahl, Steven S. Chemistry, 4th ed.; Houghton Mifflin: Boston, 1997; pp 883-884.
(4) - Zumdahl, Steven S. Chemistry, 4th ed.; Houghton Mifflin: Boston, 1997; p 884.
(5) - Kotz, Treichel, and Weaver. Chemistry & Chemical Reactivity, 6th ed.:Thomson Brooks/Cole: Belmont, CA, 2006; p 1028.
(6) - Gillespie, Ronald J., Eaton, Donald R., Humphreys, David A., and Robinson, Edward A. Atoms, Molecules, and Reactions; Prentice-Hall: Englewood Cliffs, NJ, 1994; p 604.
(7) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 930.
(8) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 7.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(11) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(13) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(14) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(15) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(16) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(17) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(18) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(19) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(20) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(21) - Kotz, John C. and Treichel, Paul. Chemistry & Chemical Reactivity 4th ed.; Thomson Brooks/Cole: Belmont, CA, 1999; p 173.
(22) - Kotz, John C. and Treichel, Paul. Chemistry & Chemical Reactivity 4th ed.; Thomson Brooks/Cole: Belmont, CA, 1999; p 151.
(23) - Kotz, John C. and Treichel, Paul. Chemistry & Chemical Reactivity 4th ed.; Thomson Brooks/Cole: Belmont, CA, 1999; p 158.
(24) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 382.
(25) - Atkins, Jones, and Laverman. Chemical Principles 6th ed.; W.H. Freeman and Company: New York, NY, 2013; p F94.
(26) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(27) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(28) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 962.
(29) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 964.
(30) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(31) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.
(32) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 7:17.