MAGNESIUM

Introduction

Atomic Number: 12
Group: 2 or II A
Atomic Weight: 24.305
Period: 3
CAS Number: 7439-95-4

Classification

Chalcogen
Halogen
Noble Gas
Lanthanoid
Actinoid
Rare Earth Metal
Platinum Group Metal
Transuranium
No Stable Isotopes
Solid
Liquid
Gas
Solid (Predicted)

Description

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

Uses/Function

•(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

Physical Properties

Melting Point:9*  650 °C = 923.15 K = 1202 °F
Boiling Point:9* 1090 °C = 1363.15 K = 1994 °F
Sublimation Point:9 
Triple Point:9 
Critical Point:9 
Density:10  1.74 g/cm3

* - at 1 atm

Electron Configuration

Electron Configuration: [Ne] 3s2
Block: s
Highest Occupied Energy Level: 3
Valence Electrons: 2

Quantum Numbers:

n = 3
ℓ = 0
m = 0
ms = -½

Bonding

Electronegativity (Pauling scale):11 1.31
Electropositivity (Pauling scale): 2.69
Electron Affinity:12 not stable eV
Oxidation States: +2
Work Function:13 3.66 eV = 5.86332E-19 J

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

Thermochemistry

Specific Heat: 1.023 J/g°C 15 = 24.864 J/mol°C = 0.245 cal/g°C = 5.943 cal/mol°C
Thermal Conductivity: 156 (W/m)/K, 27ºC 16
Heat of Fusion: 8.954 kJ/mol 17 = 368.4 J/g
Heat of Vaporization: 127.4 kJ/mol 18 = 5241.7 J/g
State of Matter Enthalpy of Formation (ΔHf°)19 Entropy (S°)19 Gibbs Free Energy (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

Isotopes

Nuclide Mass 20 Half-Life 20 Nuclear Spin 20 Binding Energy
19Mg 19.03547(27) 1/2-# 107.42 MeV
20Mg 20.018863(29) 90.8(24) ms 0+ 131.34 MeV
21Mg 21.011713(18) 122(2) ms (5/2,3/2)+ 145.94 MeV
22Mg 21.9995738(14) 3.8755(12) s 0+ 165.20 MeV
23Mg 22.9941237(14) 11.317(11) s 3/2+ 177.94 MeV
24Mg 23.985041700(14) STABLE 0+ 194.40 MeV
25Mg 24.98583692(3) STABLE 5/2+ 202.48 MeV
26Mg 25.982592929(30) STABLE 0+ 213.35 MeV
27Mg 26.98434059(5) 9.458(12) min 1/2+ 219.57 MeV
28Mg 27.9838768(22) 20.915(9) h 0+ 228.58 MeV
29Mg 28.988600(15) 1.30(12) s 3/2+ 232.00 MeV
30Mg 29.990434(9) 335(17) ms 0+ 238.21 MeV
31Mg 30.996546(13) 230(20) ms 3/2+ 240.70 MeV
32Mg 31.998975(19) 86(5) ms 0+ 246.92 MeV
33Mg 33.005254(21) 90.5(16) ms 7/2-# 248.47 MeV
34Mg 34.00946(25) 20(10) ms 0+ 252.83 MeV
35Mg 35.01734(43)# 70(40) ms (7/2-)# 253.45 MeV
36Mg 36.02300(54)# 3.9(13) ms 0+ 255.94 MeV
37Mg 37.03140(97)# 40# ms [>260 ns] 7/2-# 256.57 MeV
38Mg 38.03757(54)# 1# ms [>260 ns] 0+ 259.06 MeV
39Mg 39.04677(55)# <260 ns 7/2-# 258.75 MeV
40Mg 40.05393(97)# 1# ms 0+ 260.31 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. 20

Reactions

Abundance

Earth - Source Compounds: carbonates/sulfates 28
Earth - Seawater: 1290 mg/L 29
Earth -  Crust:  23300 mg/kg = 2.33% 29
Earth -  Mantle:  16.6% 30
Earth -  Lithosphere:  2.76% 31
Earth -  Hydrosphere:  0.13% 31
Earth -  Total:  13.90% 32
Mercury -  Total:  6.50% 32
Venus -  Total:  14.54% 32
Universe -  Total:  0.06% 30
Chondrites - Total: 9.4×105 (relative to 106 atoms of Si) 33
Human Body - Total: 0.027% 34

Compounds

Prices





Safety Information


Material Safety Data Sheet - ACI Alloys, Inc.

Languages

Afrikaans:   Magnesium
Albanian:   Magnez
Armenian:   Մագնեզիում
Arabic:   مغنيزيوم
Aromanian:   Magneziumu
Basque:   Magnesioa
Bosnian:   Magnezij
Breton:   Magnesiom
Bulgarian:   Магнезий
Belarusian:   Магній
Catalan :   Magnesi
Chinese :   镁
Cornish :   Magnysyum
Croatian :   Magnezij
Czech :   Horcík
Danish:   Magnesium
Dutch:   Magnesium
Esperanto:   Magnezio
Estonian:   Magneesium
Faroese:   Magnesium
Finnish:   Magnesium
French:   Magnésium
Friulan: Magnesi
Frisian:   Magnesium
Galician:   Magnesio
Georgian:   მაგნიუმი
German:   Magnesium
Greek:   Μαγνησιο
Hebrew:   מגנזיום
Hungarian:   Magnézium
Icelandic:   Magnesín
Irish Gaelic:   Maignéisiam
Italian:   Magnesio
Japanese:   マグネシウム
Kashubian:   Magnéz
Kazakh:   Магний
Korean:   마그네슘
Latvian:   Magnijs
Lithuanian:   Magnis
Luxembourgish:   Magnesium
Macedonian:   Магнезиум
Malay:   Magnesium
Maltese :   Magnizjum
Manx Gaelic:   Magnaishum
Moksha:   Магни
Mongolian:   Магни
Norwegian:   Magnesium
Occitan:   Magnèsi
Ossetian:   Магний
Polish:   Magnez
Portuguese:   Magnésio
Russian:   Магний
Scottish Gaelic:   Maignèisiam
Serbian:   Магнезиjум
Slovak:   Horcík
Spanish:   Magnesio
Sudovian:   Magnijan
Swahili:   Magnesi
Swedish:   Magnesium
Tajik:   Magni'
Thai:   แมกนีเซียม
Turkish:   Magnezyum
Ukranian:   Магній
Uzbek:   Магний
Vietnamese:   Magiê
Welsh:   Magnesiwm

For More Information

External Links:

Sources

(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.
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(20) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(21) -
(22) - Kotz, John C. and Treichel, Paul. Chemistry & Chemical Reactivity 4th ed.; Thomson Brooks/Cole: Belmont, CA, 1999; p 173.
(23) -
(24) - Kotz, John C. and Treichel, Paul. Chemistry & Chemical Reactivity 4th ed.; Thomson Brooks/Cole: Belmont, CA, 1999; p 151.
(25) - Kotz, John C. and Treichel, Paul. Chemistry & Chemical Reactivity 4th ed.; Thomson Brooks/Cole: Belmont, CA, 1999; p 158.
(26) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 382.
(27) -
(28) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(29) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(30) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 962.
(31) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 964.
(32) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(33) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.
(34) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 7:17.