Magnesium (Mg)

Silvery metallic element belonging to group 2 of the periodic table (alkaline-earth metals). It is essential for living organisms, and is used in a number of light alloys. Chemically very reactive, it forms a protective oxide coating when exposed to air and burns with an intense white flame. It also reacts with sulphur, nitrogen and the halogens. First isolated by Bussy in 1828.

Atomic Number	12
Atomic Weight	24.305
Mass Number	24

Group	2
Period	3
Block	s

Protons	12 p⁺
Neutrons	12 n⁰
Electrons	12 e^-

Properties

Energy
Atomic Radius	150 pm 240 pm
Molar Volume	14 cm³/mol
Covalent Radius	139 pm 132 pm 127 pm 142 pm 141 pm
Metallic Radius	136 pm 160 pm
Ionic Radius	57 pm 66 pm 72 pm 89 pm
Crystal Radius	71 pm 80 pm 86 pm 103 pm
Van der Waals Radius	220 pm 173 pm 173 pm 243 pm 302.1 pm
Density	1.74 g/cm³ 1,584 kg/m³
Proton Affinity	819.6 kJ/mol
Electron Affinity
Ionization Energy	7.646235 eV/particle 15.035267 eV/particle 80.1436 eV/particle 109.2654 eV/particle 141.335 eV/particle 186.76 eV/particle 225.015 eV/particle 265.924 eV/particle 327.985 eV/particle 367.5 eV/particle 1,761.80481 eV/particle 1,962.664 eV/particle
Heat of Vaporization	131.8 kJ/mol
Heat of Fusion	9.2 kJ/mol
Heat of Formation	147.1 kJ/mol
Electrons
Electron Shells	2, 8, 2
Valence Electrons	2
Electron Configuration	[Ne] 3s²
Oxidation States	0, 1, 2
Electronegativity	7.646 eV/particle 0.121644 1.31
Electrophilicity
Phases
Phase	Solid
Gas Phase
Boiling Point	1,363.15 K
Melting Point	923.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color	Silver #228b22 #8aff00 #8aff00
Appearance	shiny grey solid
Refractive Index
Thermodynamic Properties
Thermal Conductivity	156 W/(m K)
Thermal Expansion	0.0000248 1/K
Molar Heat Capacity	24.869 J/(mol K)
Specific Heat Capacity	1.023 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
Type	Conductor
Electrical Conductivity	23 MS/m
Electrical Resistivity	0.00000004399999999999 m Ω
Superconducting Point
Magnetism
Type	paramagnetic
Magnetic Susceptibility (Mass)	0.0000000069 m³/Kg
Magnetic Susceptibility (Molar)	0.000000000168 m³/mol
Magnetic Susceptibility (Volume)	0.000012
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal Structure	Simple Hexagonal (HEX)
Lattice Constant	3.21 Å
Lattice Angles	π/2, π/2, 2 π/3
Mechanical Properties
Hardness	260 MPa 2.5 MPa
Bulk Modulus	45 GPa
Shear Modulus	17 GPa
Young Modulus	45 GPa
Poisson Ratio	0.29
Speed of Sound	4,602 m/s
Classification
Category	Alkaline earth metals, Alkaline earth metals
CAS Group	IIA
IUPAC Group	IIA
Glawe Number	73
Mendeleev Number	76
Pettifor Number	73
Geochemical Class	major
Goldschmidt Class	litophile
Other
Gas Basicity	797.3 kJ/mol
Dipole Polarizability	71.2 ± 0.4 a₀
C6 Dispersion Coefficient	626 a₀ 629 a₀
Allotropes
Neutron Cross Section	0.063
Neutron Mass Absorption	0.0001
Quantum Numbers	1S0
Space Group	194 (P63/mmc)

Isotopes of Magnesium

Stable Isotopes	3
Unstable Isotopes	20
Radioactive Isotopes	18

¹⁹Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	19.03417992 ± 0.000064413 Da
Mass Number	19
G-Factor
Half Life	5 ± 3 ps
Spin	1/2
Quadrupole Moment	0
Discovery Year	2007
Parity	-

¹⁹Mg Decay Modes

Decay Mode	Intensity
2p (2-proton emission)	100%

²⁰Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	20.018763075 ± 0.000002 Da
Mass Number	20
G-Factor	0
Half Life	90.4 ± 0.5 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1974
Parity	+

²⁰Mg Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	30.3%

²¹Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	21.011705764 ± 0.00000081 Da
Mass Number	21
G-Factor	-0.3932 ± 0.0028
Half Life	120 ± 0.4 ms
Spin	5/2
Quadrupole Moment
Discovery Year	1963
Parity	+

²¹Mg Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	20.1%
β⁺α (β⁺-delayed α emission)	0.116%
B+pA	0.016%

²²Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	21.999570597 ± 0.00000017 Da
Mass Number	22
G-Factor	0
Half Life	3.8745 ± 0.0007 s
Spin	0
Quadrupole Moment	0
Discovery Year	1961
Parity	+

²²Mg Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

²³Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	22.994123768 ± 0.000000034 Da
Mass Number	23
G-Factor	-0.35753333333333 ± 0.0002
Half Life	11.3039 ± 0.0032 s
Spin	3/2
Quadrupole Moment	0.114 ± 0.003
Discovery Year	1939
Parity	+

²³Mg Decay Modes

Decay Mode	Intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

²⁴Mg

Abundance	78.965 ± 0.049
Relative Atomic Mass	23.985041689 ± 0.000000013 Da
Mass Number	24
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	1920
Parity	+

²⁵Mg

Abundance	10.011 ± 0.013
Relative Atomic Mass	24.985836966 ± 0.00000005 Da
Mass Number	25
G-Factor	-0.342132 ± 0.000012
Half Life
Spin	5/2
Quadrupole Moment	0.199 ± 0.002
Discovery Year	1920
Parity	+

²⁶Mg

Abundance	11.025 ± 0.038
Relative Atomic Mass	25.982592972 ± 0.000000031 Da
Mass Number	26
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	1920
Parity	+

²⁷Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	26.984340647 ± 0.00000005 Da
Mass Number	27
G-Factor	-0.8212 ± 0.003
Half Life	9.435 ± 0.027 m
Spin	1/2
Quadrupole Moment	0
Discovery Year	1934
Parity	+

²⁷Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

²⁸Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	27.983875426 ± 0.00000028 Da
Mass Number	28
G-Factor	0
Half Life	20.915 ± 0.009 h
Spin	0
Quadrupole Moment	0
Discovery Year	1953
Parity	+

²⁸Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

²⁹Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	28.988607163 ± 0.000000369 Da
Mass Number	29
G-Factor
Half Life	1.3 ± 0.12 s
Spin	3/2
Quadrupole Moment	-0.16 ± 0.04
Discovery Year	1971
Parity	+

²⁹Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%

³⁰Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	29.990465454 ± 0.00000139 Da
Mass Number	30
G-Factor	0
Half Life	317 ± 4 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1971
Parity	+

³⁰Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	0.06%

³¹Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	30.996648232 ± 0.0000033 Da
Mass Number	31
G-Factor
Half Life	270 ± 2 ms
Spin	1/2
Quadrupole Moment	0
Discovery Year	1977
Parity	+

³¹Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	6.2%

³²Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	31.999110138 ± 0.0000035 Da
Mass Number	32
G-Factor	0
Half Life	80.4 ± 0.4 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1977
Parity	+

³²Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	5.5%

³³Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	33.005327862 ± 0.000002859 Da
Mass Number	33
G-Factor
Half Life	92 ± 1.2 ms
Spin	3/2
Quadrupole Moment	0.13 ± 0.09
Discovery Year	1979
Parity	-

³³Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	14%
2n (2-neutron emission)	%

³⁴Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	34.008935455 ± 0.0000074 Da
Mass Number	34
G-Factor	0
Half Life	44.9 ± 0.4 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1979
Parity	+

³⁴Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	21%
2n (2-neutron emission)	0.1%

³⁵Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	35.01679 ± 0.0002895 Da
Mass Number	35
G-Factor
Half Life	11.3 ± 0.6 ms
Spin	3/2
Quadrupole Moment
Discovery Year	1989
Parity	-

³⁵Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	52%
2n (2-neutron emission)	%

³⁶Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	36.021879 ± 0.000741 Da
Mass Number	36
G-Factor	0
Half Life	3.9 ± 1.3 ms
Spin	0
Quadrupole Moment	0
Discovery Year	1989
Parity	+

³⁶Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	48%
2n (2-neutron emission)	%

³⁷Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	37.030286265 ± 0.00075035 Da
Mass Number	37
G-Factor
Half Life	8 ± 4 ms
Spin	3/2
Quadrupole Moment
Discovery Year	1996
Parity	-

³⁷Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

³⁸Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	38.03658 ± 0.00054 Da
Mass Number	38
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	1997
Parity	+

³⁸Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

³⁹Mg

Abundance
Relative Atomic Mass	39.045921 ± 0.000551 Da
Mass Number	39
G-Factor
Half Life
Spin	7/2
Quadrupole Moment
Discovery Year
Parity	-

³⁹Mg Decay Modes

Decay Mode	Intensity
n (neutron emission)	%
β⁻ (β⁻ decay)	%

⁴⁰Mg

Abundance	Radioactive ☢️
Relative Atomic Mass	40.053194 ± 0.000537 Da
Mass Number	40
G-Factor	0
Half Life
Spin	0
Quadrupole Moment	0
Discovery Year	2007
Parity	+

⁴⁰Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	%
β⁻ n (β⁻-delayed neutron emission)	%
2n (2-neutron emission)	%

⁴¹Mg

Abundance
Relative Atomic Mass	41.062373 ± 0.000537 Da
Mass Number	41
G-Factor
Half Life
Spin	3/2
Quadrupole Moment
Discovery Year
Parity	-

⁴¹Mg Decay Modes

Decay Mode	Intensity
β⁻ (β⁻ decay)	%
β⁻ n (β⁻-delayed neutron emission)	%

History

Scottish chemist Joseph Black recognized magnesium as an element in 1755. Magnesium was first isolated by Sir Humphry Davy in 1808, in London. He used electrolysis on a mixture of magnesia and mercuric oxide. Antoine Bussy prepared it in coherent form in 1831. From Magnesia, district in Thessaly

Discoverers	Sir Humphrey Davy
Discovery Location	England
Discovery Year	1808
Etymology (Name Origin)	From Magnesia ancient city in district of Thessaly, Greece.
Pronunciation	mag-NEE-zih-em (English)

Because serious fires can occur, great care should be taken in handling magnesium metal

When it burns in air, magnesium produces a brilliant white light

Uses

Magnesium is widely used in the manufacturing of mobile phones, laptop computers, cameras, and other electronic components. The brilliant light it produces when ignited is made use of in photography, flares, pyrotechnics and incendiary bombs. Magnesium compounds such as the hydroxide (milk of magnesia), sulfate (Epsom salts), chloride and citrate are used for medicinal purposes. Used in alloys to make airplanes, missiles and other uses for light metals. Has structural properties similar to aluminium. But since it is flammable at temperatures of burning gasoline, its uses are limited.

Sources

Usually obtained by electrolysis of melted magnesium chloride (MgCl2) found in sea water. Each cubic mile of seawater contains about 12 billion pounds of magnesium.

Abundance
Abundance in Earth's crust	23,300 mg/kg
Abundance in Oceans	1,290 mg/L
Abundance in Human Body	0.027 %
Abundance in Meteor	12 %
Abundance in Sun	0.07 %
Abundance in Universe	0.06 %

Nuclear Screening Constants

1	s	0.3911
2	p	4.1742
2	s	4.608
3	s	8.6925

Magnesium on ChemicalAid

Art & Architecture Thesaurus ID	300011024
Australian Educational Vocabulary ID	scot/3540
BNCF Thesaurus ID	34769
Biblioteca Nacional de España ID	XX530348
Bibliothèque nationale de France ID	119771902
Brockhaus Enzyklopädie online ID	magnesium
CAS Registry Number	7439-95-4
ChEBI ID	25107
ChemSpider ID	4575328
CosIng number	87337
DSSTOX compound identifier	DTXCID70876310
DSSTox substance ID	DTXSID0049658
Den Store Danske ID	magnesium
DrugBank ID	14513
ECHA Substance Infocard ID	100.028.276
Encyclopedia of China Online Database ID (Second Edition)	220792
Encyclopædia Britannica Online ID	science/magnesium
Encyclopædia Universalis ID	magnesium
English Vikidia ID	Magnesium
EuroVoc ID	1736
Freebase ID	/m/025s0s0
French Vikidia ID	Magnésium
GND ID	4128915-8
Gran Enciclopèdia Catalana ID	0233796
Great Russian Encyclopedia Online ID	2152449
HCIS ID	2785
HSDB ID	654
ICSC ID	0701
ICSC ID	0289
InChI	InChI=1S/Mg
InChIKey	FYYHWMGAXLPEAU-UHFFFAOYSA-N
Italian Vikidia ID	Magnesio
KBpedia ID	Magnesium
Latvian National Encyclopedia Online ID	94910
Library of Congress authority ID	sh85079651
MeSH descriptor ID	D008274
MinDat mineral ID	52650
NALT ID	6422
NDF-RT ID	N0000146038
NE.se ID	magnesium
NKCR AUT ID	ph120851
Namuwiki ID	마그네슘
National Diet Library ID	00567385
National Library of Israel J9U ID	987007543565105171
OmegaWiki Defined Meaning	158358
OpenAlex ID	C543218039
Open Food Facts ingredient ID	magnesium
PACTOLS thesaurus ID	pcrtQe4n9vGjl0
PSH ID	5751
PatientsLikeMe treatment ID	magnesium
PubChem CID	5462224
Quora topic ID	Magnesium
RxNorm ID	6574
STW Thesaurus for Economics ID	14300-4
Spanish Vikidia ID	Magnesio
Store norske leksikon ID	magnesium
Treccani ID	magnesio
U.S. National Archives Identifier	10646571
UK Parliament thesaurus ID	11483
UMLS CUI	C0024467
UNII	I38ZP9992A
WikiSkripta ID	1272
WordNet 3.1 Synset ID	14668427-n
YSO ID	3518
ZVG number	500042
ZVG number	8090
ZVG number	7120

Magnesium (Mg)

Properties

Isotopes of Magnesium

19Mg

19Mg Decay Modes

20Mg

20Mg Decay Modes

21Mg

21Mg Decay Modes

22Mg

22Mg Decay Modes

23Mg

23Mg Decay Modes

24Mg

25Mg

26Mg

27Mg

27Mg Decay Modes

28Mg

28Mg Decay Modes

29Mg

29Mg Decay Modes

30Mg

30Mg Decay Modes

31Mg

31Mg Decay Modes

32Mg

32Mg Decay Modes

33Mg

33Mg Decay Modes

34Mg

34Mg Decay Modes

35Mg

35Mg Decay Modes

36Mg

36Mg Decay Modes

37Mg

37Mg Decay Modes

38Mg

38Mg Decay Modes

39Mg

39Mg Decay Modes

40Mg

40Mg Decay Modes

41Mg

41Mg Decay Modes