Magnesium is a shiny grey alkaline metal and only occurs naturally in combination with other elements, where it invariably has a +2 oxidation state and burns with a characteristic brilliant-white light, making it a useful ingredient in flares.

1898 by Sir William Ramsay and Morris Travers, London, England.

DISCOVERY

Magnēsia, ('region in Thessaly') + -ium.

ETYMOLOGY

Magnesium

Element

Mg

Symbol

12

12 Atomic Number

Atomic Number

Alkaline Earth

Classification

7439-95-4

CAS Number

Silver

Elemental Colour

-

Refractive Index

0.29

0.29 Poisson Ratio

Poisson Ratio

13.984 cm³

Molar Volume

260.00M Pa, 2.566'0k Atm

2.566'0k Atm

Brinell Hardness

2.50

2.50 Mohs Hardness

Mohs Hardness

-

Vickers Hardness

4,602 m/s, Mach 13.416'9

4,602 m/s

Speed of Sound

45.00G Pa, 444.115'5k Atm

444.115'5k Atm

Bulk Modulus

17.00G Pa, 167.777'0k Atm

167.777'0k Atm

Shear Modulus

45.00G Pa, 444.115'5k Atm

444.115'5k Atm

Young Modulus

Allotropes

NONE

923.15 K, 650.00 °C

650.00 °C

Melting Point

1,363.15 K, 1,090.00 °C

1,090.00 °C

Boiling Point

745.15 K, 472.00 °C

472.00 °C

Automatic Ignition

773.15 K, 500.00 °C

500.00 °C

Flashpoint

-

Critical Temperature

-

Critical Pressure

160.000'000 W/(m K)

Thermal Conductivity

0.000'008'2 K^-1

Thermal Expansion

1,020 J/(kg K)

Specific Heat

8.7 kJ/mol

Heat Fusion

128 kJ/mol

Heat Vaporisation

668 J/(kg K)

Heat Combustion

-

Curie Point

-

Neel Point

-

Adiabatic Index

Solid

Phase

Conductor

Electrical Type

23.00M S/m

Conductivity

44.00n Ω.m

Resistivity

-

Superconducting Point

Paramagnetic

Magnetic Type

0.000'000'006'9

Mass Susceptibility

0.000'000'000'168'00

Molar Susceptibility

0.000'012'000'00

Volume Susceptibility

Material Composition

0.02 %

Universe

12 %

Meteorites

0.17 %

Sun

2.3 %

Earth Crust

0.13 %

Oceans

0.027 %

Humans

24.305'051'6

Atomic Weight

145 pm

Atomic Radius

139 pm

Covalent Radius Single Bond

132 pm

Covalent Radius Double Bond

127 pm

Covalent Radius Triple Bond

173 pm

Van der Waals Radius

[Ne]3s²

Electron Configuration

Hexagonal, Close Packed Single

Crystal Structure

1.738'00 g/cm³

Density as Solid

1.584'00 g/cm³

Density as Liquid

-

Density as Gas

P6₃/mmc

Space Group Name

194

194 Space Group Number

Space Group Number

π/2, π/2 & 2π/3

Lattice Angles

320.94, 320.94 & 521.08 pm

Lattice Constants

2

2 Valence

Valence

1.31

1.31 Electronegativity

Electronegativity

-38.60 kJ/mol

Electron Affinity

Ionisation Energy

Stable

Half Life

Stable

Lifetime

3s² = 3, 0, 0, -1/2

Quantum Numbers

3.710'00 b σ_s

Neutron Cross Section

0.063'00 b σ_a

Neutron Mass Absorption

Stable Isotopes

Unstable Isotopes

Isotopes Overview

Isotope	Stability	Symbol	Type	Protons	Proton Ext	Neutrons	Neutrons Ext	Spin	Parity	Mass	Mass Ext	Abundance	Abundance Ext	Mass Measure	Mass Excess	Mass Excess Ext	Binding Energy	Binding Energy Ext	Dipole Moment	Dipole Moment Ext	Quadrupole Moment	Quadrupole Moment Ext	Halflife in Years	Halflife in Years Ext	Halflife in Seconds	Halflife in Seconds Ext	A01 Decay Probability	A01 Decay Probability Ext	A01 Decay Mode	A01 Decay Energy	A01 Decay Energy Ext	A01 Decay Daughter	A01 Decay Link	A02 Decay Probability	A02 Decay Probability Ext	A02 Decay Mode	A02 Decay Energy	A02 Decay Energy Ext	A02 Decay Daughter	A02 Decay Link	A03 Decay Probability	A03 Decay Probability Ext	A03 Decay Mode	Y01 Decay Product Yield	Y01 Decay Product Yield Ext	Y01 Decay Product Nuclide	Y02 Decay Product Yield	Y02 Decay Product Yield Ext	Y02 Decay Product Nuclide	Y03 Decay Product Yield	Y03 Decay Product Yield Ext	Y03 Decay Product Nuclide	Y04 Decay Product Yield	Y04 Decay Product Yield Ext	Y04 Decay Product Nuclide
Isotope_012_mg_19_u	Unstable	¹⁹Mg	Fermion	12	p	7	n	1/2	1	19.035'470'000'0	u	~ 0	%	~ 0	33.040'092'000'0	MeV	5.838'251'000'0	MeV	-		-		1.27E-19	year	4.000	pico-seconds ( x⁻¹² )	?	%	2p	2,001.000	keV	¹⁷Ne	¹⁹Mg > [ ? % , 2p , 2,001.0 keV ] > ¹⁷Ne											?	%	¹⁶O	?	%	¹³C
Isotope_012_mg_20_u	Unstable	²⁰Mg	Boson	12	p	8	n	0	1	20.018'862'545'0	u	~ 0	%	~ 0	17.570'348'000'0	MeV	6.723'392'000'0	MeV	-		-		2.85E-9	year	90.000	milli-seconds ( x⁻³ )	70.000'000	%	β+	9,700.400	keV	²⁰Na	²⁰Mg > [ 70 % , β+ , 9,700.4 keV ] > ²⁰Na	30.400'000	%	β+p	?	keV	¹⁹Ne	²⁰Mg > [ 30.4 % , β+p , ? keV ] > ¹⁹Ne				52.444'490	%	²⁰Ne	30.400'000	%	¹⁹F	17.500'000	%	¹⁶O
Isotope_012_mg_21_u	Unstable	²¹Mg	Fermion	12	p	9	n	?	1	21.011'712'910'0	u	~ 0	%	~ 0	10.910'506'000'0	MeV	7.104'714'000'0	MeV	-		-		3.87E-9	year	122.000	milli-seconds ( x⁻³ )	67.000'000	%	β+	12,072.000	keV	²¹Na	²¹Mg > [ 67 % , β+ , 12,072.0 keV ] > ²¹Na	32.600'000	%	β+p	?	keV	²⁰Ne	²¹Mg > [ 32.6 % , β+p , ? keV ] > ²⁰Ne	0.005'000	%	¹⁷F	67.000'000	%	²¹Ne	32.600'000	%	²⁰Ne	0.500'000	%	¹⁶O
Isotope_012_mg_22_u	Unstable	²²Mg	Boson	12	p	10	n	0	1	21.999'573'843'0	u	~ 0	%	~ 0	-0.396'963'000'0	MeV	7.662'626'000'0	MeV	-		-		1.22E-7	year	3.857	seconds ( x⁰ )	100.000'000	%	β+	3,763.270	keV	²²Na	²²Mg > [ 100 % , β+ , 3,763.27 keV ] > ²²Na											100.000'000	%	³⁰Ne
Isotope_012_mg_23_u	Unstable	²³Mg	Fermion	12	p	11	n	3/2	1	22.994'123'669'0	u	~ 0	%	~ 0	-5.473'766'000'0	MeV	7.901'126'000'0	MeV	-		-		3.59E-7	year	11.317	seconds ( x⁰ )	100.000'000	%	β+	3,033.890	keV	²³Na	²³Mg > [ 100 % , β+ , 3,033.89 keV ] > ²³Na											100.000'000	%	²³Na
Isotope_012_mg_24_s	Stable	²⁴Mg	Boson	12	p	12	n	0	1	23.985'041'699'0	u	78.990'000	%	18.945'784'438'0	-13.933'567'000'0	MeV	8.260'709'000'0	MeV	-		-		-
Isotope_012_mg_25_s	Stable	²⁵Mg	Fermion	12	p	13	n	5/2	1	24.985'836'917'0	u	10.000'000	%	2.498'583'691'7	-13.192'826'000'0	MeV	8.223'504'000'0	MeV	-0.855'450'000'0	nm	0.201'000'000'0	b	-
Isotope_012_mg_26_s	Stable	²⁶Mg	Boson	12	p	14	n	0	1	25.982'592'929'0	u	11.010'000	%	2.860'683'481'5	-16.214'582'000'0	MeV	8.333'872'000'0	MeV	-		-		-
Isotope_012_mg_27_u	Unstable	²⁷Mg	Fermion	12	p	15	n	1/2	1	26.984'340'585'0	u	~ 0	%	~ 0	-14.586'651'000'0	MeV	8.263'854'000'0	MeV	-		-		1.80E-5	year	567.498	seconds ( x⁰ )	100.000'000	%	β-	2,610.007	keV	²⁷Al	²⁷Mg > [ 100 % , β- , 2,610.007 keV ] > ²⁷Al											100.000'000	%	²⁷Al
Isotope_012_mg_28_u	Unstable	²⁸Mg	Boson	12	p	16	n	0	1	27.983'876'825'0	u	~ 0	%	~ 0	-15.018'641'000'0	MeV	8.272'406'000'0	MeV	-		-		2.39E-3	year	75.294	kilo-seconds ( x³ )	100.000'000	%	β-	1,831.800	keV	²⁸Al	²⁸Mg > [ 100 % , β- , 1,831.8 keV ] > ²⁸Al											100.000'000	%	²⁸Si
Isotope_012_mg_29_u	Unstable	²⁹Mg	Fermion	12	p	17	n	3/2	1	28.988'600'000'0	u	~ 0	%	~ 0	-10.619'032'000'0	MeV	8.113'761'000'0	MeV	-		-		4.12E-8	year	1.300	seconds ( x⁰ )	100.000'000	%	β-	7,596.300	keV	²⁹Al	²⁹Mg > [ 100 % , β- , 7,596.3 keV ] > ²⁹Al											100.000'000	%	²⁹Si
Isotope_012_mg_30_u	Unstable	³⁰Mg	Boson	12	p	18	n	0	1	29.990'434'000'0	u	~ 0	%	~ 0	-8.910'672'000'0	MeV	8.055'401'000'0	MeV	-		-		1.06E-8	year	335.000	milli-seconds ( x⁻³ )	100.000'000	%	β-	6,961.700	keV	³⁰Al	³⁰Mg > [ 100 % , β- , 6,961.7 keV ] > ³⁰Al	0.060'000	%	β-n	1,233.330	keV	³⁰Al	³⁰Mg > [ 0.06 % , β-n , 1,233.33 keV ] > ³⁰Al				100.000'000	%	³⁰Si	0.060'000	%	²⁹Si
Isotope_012_mg_31_u	Unstable	³¹Mg	Fermion	12	p	19	n	3/2	1	30.996'546'000'0	u	~ 0	%	~ 0	-3.217'380'000'0	MeV	7.872'260'000'0	MeV	-		-		7.29E-9	year	230.000	milli-seconds ( x⁻³ )	94.000'000	%	β-	11,736.200	keV	³¹Al	³¹Mg > [ 94 % , β- , 11,736.2 keV ] > ³¹Al	6.200'000	%	β-n	4,583.700	keV	³⁰Al	³¹Mg > [ 6.2 % , β-n , 4,583.7 keV ] > ³⁰Al				92.119'900	%	³¹P	7.704'000	%	²⁸Si
Isotope_012_mg_32_u	Unstable	³²Mg	Boson	12	p	20	n	0	1	31.998'975'000'0	u	~ 0	%	~ 0	-0.954'781'000'0	MeV	7.807'774'000'0	MeV	-		-		3.01E-9	year	95.000	milli-seconds ( x⁻³ )	98.000'000	%	β-	10,107.200	keV	³²Al	³²Mg > [ 98 % , β- , 10,107.2 keV ] > ³²Al	2.400'000	%	β-n	5,927.500	keV	³⁰Al	³²Mg > [ 2.4 % , β-n , 5,927.5 keV ] > ³⁰Al				97.020'000	%	³²P	3.038'000	%	³¹P	0.038'400	%	³⁰Si
Isotope_012_mg_33_u	Unstable	³³Mg	Fermion	12	p	21	n	7/2	-1	33.005'254'000'0	u	~ 0	%	~ 0	4.894'070'000'0	MeV	7.638'522'000'0	MeV	-		-		2.87E-9	year	90.500	milli-seconds ( x⁻³ )	83.000'000	%	β-	13,423.400	keV	³³Al	³³Mg > [ 83 % , β- , 13,423.4 keV ] > ³³Al	17.000'000	%	β-n	7,884.700	keV	³²Al	³³Mg > [ 17 % , β-n , 7,884.7 keV ] > ³²Al				76.360'000	%	³³S	23.885'000	%	³²S	0.119'000	%	³¹P
Isotope_012_mg_34_u	Unstable	³⁴Mg	Boson	12	p	22	n	0	1	34.009'456'424'0	u	~ 0	%	~ 0	8.808'603'000'0	MeV	7.536'118'000'0	MeV	-		-		6.34E-10	year	20.000	milli-seconds ( x⁻³ )	100.000'000	%	β-	11,741.000	keV	³⁴Al	³⁴Mg > [ 100 % , β- , 11,741.0 keV ] > ³⁴Al	?	%	β-n	9,267.000	keV	³³Al	³⁴Mg > [ ? % , β-n , 9,267.0 keV ] > ³³Al				88.000'000	%	³⁴S	12.500'000	%	³³S	?	%	³²S
Isotope_012_mg_35_u	Unstable	³⁵Mg	Boson	12	p	23	n	7/2	1	35.017'340'000'0	u	~ 0	%	~ 0	16.152'000'000'0	MeV	7.342'000'000'0	MeV	-		-		2.22E-9	year	70.000	milli-seconds ( x⁻³ )	52.000'000	%	β-n	11,013.000	keV	³⁴Al	³⁵Mg > [ 52 % , β-n , 11,013.0 keV ] > ³⁴Al	48.000'000	%	β-	16,282.000	keV	³⁵Al	³⁵Mg > [ 48 % , β- , 16,282.0 keV ] > ³⁵Al				66.856'000	%	³⁴S	26.904'000	%	³⁵Cl	6.500'000	%	³³S
Isotope_012_mg_36_u	Unstable	³⁶Mg	Boson	12	p	24	n	0	1	36.023'000'000'0	u	~ 0	%	~ 0	21.424'000'000'0	MeV	7.215'000'000'0	MeV	-		-		1.58E-10	year	5.000	milli-seconds ( x⁻³ )	?	%	β-	15,642.000	keV	³⁶Al	³⁶Mg > [ ? % , β- , 15,642.0 keV ] > ³⁶Al											?	%	³⁶S	?	%	³⁴S	?	%	³⁵Cl
Isotope_012_mg_37_u	Unstable	³⁷Mg	Fermion	12	p	25	n	7/2	-1	37.031'400'000'0	u	~ 0	%	~ 0	29.249'000'000'0	MeV	7.027'000'000'0	MeV	-		-		1.27E-9	year	40.000	milli-seconds ( x⁻³ )	?	%	β-	19,303.000	keV	³⁷Al	³⁷Mg > [ ? % , β- , 19,303.0 keV ] > ³⁷Al	?	%	β-n	15,396.000	keV	³⁷Al	³⁷Mg > [ ? % , β-n , 15,396.0 keV ] > ³⁷Al				?	%	³⁶S	?	%	³⁴S	?	%	³⁷Cl	?	%	³⁵Cl
Isotope_012_mg_38_u	Unstable	³⁸Mg	Boson	12	p	26	n	0	1	38.037'570'000'0	u	~ 0	%	~ 0	34.996'000'000'0	MeV	6.903'000'000'0	MeV	-		-		3.17E-11	year	1.000	milli-seconds ( x⁻³ )	?	%	β-	18,946.000	keV	³⁸Al	³⁸Mg > [ ? % , β- , 18,946.0 keV ] > ³⁸Al											?	%	³⁷Cl	?	%	³⁸Ar
Isotope_012_mg_39_u	Unstable	³⁹Mg	Fermion	12	p	27	n	7/2	-1	39.046'772'000'0	u	~ 0	%	~ 0	43.568'000'000'0	MeV	6.713'000'000'0	MeV	-		-		8.24E-15	year	260.000	nano-seconds ( x⁻⁹ )	?	%	n	500.000	keV	³⁸Al	³⁹Mg > [ ? % , n , 500.0 keV ] > ³⁸Al											?	%	³⁷Cl	?	%	³⁸Ar
Isotope_012_mg_40_u	Unstable	⁴⁰Mg	Boson	12	p	28	n	0	1	40.053'930'000'0	u	~ 0	%	~ 0	50.235'000'000'0	MeV	6.581'000'000'0	MeV	-		-		3.17E-11	year	1.000	milli-seconds ( x⁻³ )	?	%	β-	20,940.000	keV	⁴⁰Al	⁴⁰Mg > [ ? % , β- , 20,940.0 keV ] > ⁴⁰Al	?	%	β-n	20,770.000	keV	³⁹Al	⁴⁰Mg > [ ? % , β-n , 20,770.0 keV ] > ³⁹Al				?	%	³⁹K	?	%	⁴⁰Ar	?	%	³⁸Ar

12 – Magnesium, Mg

12 – Magnesium, Mg

12 – Magnesium, Mg

12 – Magnesium, Mg

12 – Magnesium, Mg

Spectrograph

Elemental Tile

Magnesium

Spectrograph

Elemental Tile

Magnesium

Spectrograph

Elemental Tile

Magnesium

Spectrograph

Elemental Tile

Magnesium

Spectrograph

Elemental Tile

Magnesium