Magnesium

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 Number12
Atomic Weight24.305
Mass Number24
Group2
Period3
Blocks
Protons12 p+
Neutrons12 n0
Electrons12 e-
Magnesium crystals.jpg Animated Bohr Model of Mg (Magnesium) Enhanced Bohr Model of Mg (Magnesium) Bohr Model: Mg (Magnesium) Orbital Diagram of Mg (Magnesium)

Properties

Atomic Radius
150 pm
Molar Volume
Covalent Radius
139 pm
Metallic Radius
136 pm
Ionic Radius
57 pm
Crystal Radius
71 pm
Van der Waals Radius
173 pm
Density
1.74 g/cm³
Energy
Proton Affinity
819.6 kJ/mol
Electron Affinity
Ionization Energy
7.646235 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 Shells2, 8, 2
Valence Electrons2
Electron Configuration[Ne] 3s2
Oxidation States0, 1, 2
Electronegativity
1.31
Electrophilicity
Phases
PhaseSolid
Gas Phase
Boiling Point
1,363.15 K
Melting Point
923.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Silver
Appearanceshiny grey solid
Refractive Index
Thermodynamic Properties
Thermal Conductivity
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
TypeConductor
Electrical Conductivity
23 MS/m
Electrical Resistivity
0.00000004399999999999 m Ω
Superconducting Point
Magnetism
Typeparamagnetic
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 StructureSimple Hexagonal (HEX)
Lattice Constant
3.21 Å
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
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
CategoryAlkaline earth metals, Alkaline earth metals
CAS GroupIIA
IUPAC GroupIIA
Glawe Number73
Mendeleev Number76
Pettifor Number73
Geochemical Classmajor
Goldschmidt Classlitophile
Other
Gas Basicity
797.3 kJ/mol
Dipole Polarizability
71.2 ± 0.4 a₀
C6 Dispersion Coefficient
626 a₀
Allotropes
Neutron Cross Section
0.063
Neutron Mass Absorption
0.0001
Quantum Numbers1S0
Space Group194 (P63/mmc)

Isotopes of Magnesium

Stable Isotopes3
Unstable Isotopes20
Radioactive Isotopes18

19Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
19.03417992 ± 0.000064413 Da
Mass Number19
G-Factor
Half Life
5 ± 3 ps
Spin1/2
Quadrupole Moment
0
Discovery Year2007
Parity-

19Mg Decay Modes
Decay ModeIntensity
2p (2-proton emission)100%

20Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
20.018763075 ± 0.000002 Da
Mass Number20
G-Factor
0
Half Life
90.4 ± 0.5 ms
Spin0
Quadrupole Moment
0
Discovery Year1974
Parity+

20Mg Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)30.3%

21Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
21.011705764 ± 0.00000081 Da
Mass Number21
G-Factor
-0.3932 ± 0.0028
Half Life
120 ± 0.4 ms
Spin5/2
Quadrupole Moment
Discovery Year1963
Parity+

21Mg Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)20.1%
β+α (β+-delayed α emission)0.116%
B+pA0.016%

22Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
21.999570597 ± 0.00000017 Da
Mass Number22
G-Factor
0
Half Life
3.8745 ± 0.0007 s
Spin0
Quadrupole Moment
0
Discovery Year1961
Parity+

22Mg Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

23Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
22.994123768 ± 0.000000034 Da
Mass Number23
G-Factor
-0.35753333333333 ± 0.0002
Half Life
11.3039 ± 0.0032 s
Spin3/2
Quadrupole Moment
0.114 ± 0.003
Discovery Year1939
Parity+

23Mg Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

24Mg

Abundance
78.965 ± 0.049
Relative Atomic Mass
23.985041689 ± 0.000000013 Da
Mass Number24
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1920
Parity+

25Mg

Abundance
10.011 ± 0.013
Relative Atomic Mass
24.985836966 ± 0.00000005 Da
Mass Number25
G-Factor
-0.342132 ± 0.000012
Half Life
Spin5/2
Quadrupole Moment
0.199 ± 0.002
Discovery Year1920
Parity+

26Mg

Abundance
11.025 ± 0.038
Relative Atomic Mass
25.982592972 ± 0.000000031 Da
Mass Number26
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1920
Parity+

27Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
26.984340647 ± 0.00000005 Da
Mass Number27
G-Factor
-0.8212 ± 0.003
Half Life
9.435 ± 0.027 m
Spin1/2
Quadrupole Moment
0
Discovery Year1934
Parity+

27Mg Decay Modes
Decay ModeIntensity
β (β decay)100%

28Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
27.983875426 ± 0.00000028 Da
Mass Number28
G-Factor
0
Half Life
20.915 ± 0.009 h
Spin0
Quadrupole Moment
0
Discovery Year1953
Parity+

28Mg Decay Modes
Decay ModeIntensity
β (β decay)100%

29Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
28.988607163 ± 0.000000369 Da
Mass Number29
G-Factor
Half Life
1.3 ± 0.12 s
Spin3/2
Quadrupole Moment
-0.16 ± 0.04
Discovery Year1971
Parity+

29Mg Decay Modes
Decay ModeIntensity
β (β decay)100%

30Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
29.990465454 ± 0.00000139 Da
Mass Number30
G-Factor
0
Half Life
317 ± 4 ms
Spin0
Quadrupole Moment
0
Discovery Year1971
Parity+

30Mg Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)0.06%

31Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
30.996648232 ± 0.0000033 Da
Mass Number31
G-Factor
Half Life
270 ± 2 ms
Spin1/2
Quadrupole Moment
0
Discovery Year1977
Parity+

31Mg Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)6.2%

32Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
31.999110138 ± 0.0000035 Da
Mass Number32
G-Factor
0
Half Life
80.4 ± 0.4 ms
Spin0
Quadrupole Moment
0
Discovery Year1977
Parity+

32Mg Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)5.5%

33Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
33.005327862 ± 0.000002859 Da
Mass Number33
G-Factor
Half Life
92 ± 1.2 ms
Spin3/2
Quadrupole Moment
0.13 ± 0.09
Discovery Year1979
Parity-

33Mg Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)14%
2n (2-neutron emission)%

34Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
34.008935455 ± 0.0000074 Da
Mass Number34
G-Factor
0
Half Life
44.9 ± 0.4 ms
Spin0
Quadrupole Moment
0
Discovery Year1979
Parity+

34Mg Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)21%
2n (2-neutron emission)0.1%

35Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
35.01679 ± 0.0002895 Da
Mass Number35
G-Factor
Half Life
11.3 ± 0.6 ms
Spin3/2
Quadrupole Moment
Discovery Year1989
Parity-

35Mg Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)52%
2n (2-neutron emission)%

36Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
36.021879 ± 0.000741 Da
Mass Number36
G-Factor
0
Half Life
3.9 ± 1.3 ms
Spin0
Quadrupole Moment
0
Discovery Year1989
Parity+

36Mg Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)48%
2n (2-neutron emission)%

37Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
37.030286265 ± 0.00075035 Da
Mass Number37
G-Factor
Half Life
8 ± 4 ms
Spin3/2
Quadrupole Moment
Discovery Year1996
Parity-

37Mg Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

38Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
38.03658 ± 0.00054 Da
Mass Number38
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1997
Parity+

38Mg Decay Modes
Decay ModeIntensity
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 Number39
G-Factor
Half Life
Spin7/2
Quadrupole Moment
Discovery Year
Parity-

39Mg Decay Modes
Decay ModeIntensity
n (neutron emission)%
β (β decay)%

40Mg

AbundanceRadioactive ☢️
Relative Atomic Mass
40.053194 ± 0.000537 Da
Mass Number40
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year2007
Parity+

40Mg Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

41Mg

Abundance
Relative Atomic Mass
41.062373 ± 0.000537 Da
Mass Number41
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year
Parity-

41Mg Decay Modes
Decay ModeIntensity
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

DiscoverersSir Humphrey Davy
Discovery LocationEngland
Discovery Year1808
Etymology (Name Origin)From Magnesia ancient city in district of Thessaly, Greece.
Pronunciationmag-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

1s0.3911
2p4.1742
2s4.608
3s8.6925