MAGNESIUM (Mg) • Element 12 • Physical Properties/Chemical Properties • Description • Uses/Function • Isotopes • Thermochemistry • Reactions • Electron Configuration and Bonding • Video

MAGNESIUM

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Introduction

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

Classification

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Description

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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

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"(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

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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 and Bonding

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Electron Configuration:	[Ne] 3s²				Lewis Dot Diagram
						x
Block:	s					Mg	x
Highest Occupied Energy Level:	3					Mg
Valence Electrons:	2
Quantum Numbers:	n = 3	ℓ = 0	m_ℓ = 0	m_s = -½

The information in this section can be derived from the periodic table. Lewis dot diagrams and valence electrons are not useful for transition metals, lanthanides, and actinides. Only the valence electrons are shown for these elements. Quantum numbers are given for the final electron.

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

Thermochemistry

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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 Formation¹⁹		Entropy¹⁹		Gibbs Free Energy¹⁹
	(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

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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

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2 Mg (s) + O2 (g) → 2 MgO (s) ²¹
SiCl4 (ℓ) + 2 Mg (s) → Si (s) + 2 MgCl2 (s) ²²
TiCl4 (g) + 2 Mg (ℓ) → Ti (s) + 2 MgCl2 (ℓ) ²³

Abundance

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Earth:	Source Compounds:	carbonates/sulfates ²⁴
Earth:	Seawater:	1290 mg/L ²⁵
Earth:	Crust:	23300 mg/kg = 2.33% ²⁵
Earth:	Mantle:	16.6% ²⁶
Earth:	Lithosphere:	2.76% ²⁷
Earth:	Hydrosphere:	0.13% ²⁷
Earth:	Total:	13.90% ²⁸
Mercury:	Total:	6.50% ²⁸
Venus:	Total:	14.54% ²⁸
Universe:	Total:	0.06% ²⁶
Chondrites:	Total:	9.4×10⁵ (relative to 10⁶ atoms of Si) ²⁹
Human Body:	Total:	0.027% ³⁰

Compounds

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magnesium acetate	magnesium hydride	magnesium silicide
magnesium acetate tetrahydrate	magnesium hydroxide	magnesium silicite
magnesium arsenate	magnesium iodide	magnesium stearate
magnesium bromide	magnesium lauryl sulfate	magnesium succinate
magnesium bromide hexahydrate	magnesium nitrate	magnesium sulfate
magnesium carbonate	magnesium nitrate hexahydrate	magnesium sulfate heptahydrate
magnesium carbonate n-hydrate	magnesium nitride	magnesium sulfide
magnesium chloride	magnesium oxide	magnesium technetate
magnesium chloride hexahydrate	magnesium perchlorate	magnesium telluride
magnesium citrate	magnesium peroxide	magnesium titanate
magnesium ethoxide	magnesium phosphate dibasic trihydrate	magnesium trisilicate n-hydrate
magnesium fluoride	magnesium phosphide
magnesium glycerophosphate	magnesium selenide

Prices

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Material Safety Data Sheet

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ACI Alloys, Inc.

Languages

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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

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Sources

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(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 151.

(22) - Kotz, John C. and Treichel, Paul. Chemistry & Chemical Reactivity 4th ed.; Thomson Brooks/Cole: Belmont, CA, 1999; p 158.

(23) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 382.

(24) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.

(25) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.

(26) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 962.

(27) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 964.

(28) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)

(29) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.

(30) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 7:17.

Comments

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MAGNESIUM

Periodic Table

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

External Links:
About.com	American Elements
Chemical & Engineering News	Chemical Elements
ChemGlobe	Chemicool
Environmental Chemistry	Eni Generalic
HyperPhysics from Georgia State University's Department of Physics and Astronomy	InfoPlease
Lenntech	Los Alamos National Laboratory
Physics Department of the University of Coimbra	Qivx Inc.
Royal Society of Chemistry's Visual Elements	Schenectady County Community College
Thomas Jefferson Lab National Accelerator Facility	WebElements
Wikipedia	X-ray properties: Carlo Segre from Illinois Institute of Technology

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