Molybdenum

Molybdenum (Mo)

Silvery-white, hard metallic transition element. It is chemically unreactive and is not affected by most acids. It oxidizes at high temperatures. There are seven natural isotopes, and four radioisotopes, Mo-93 being the most stable with a half-life of 3500 years. Molybdenum is used in almost all high-strength steels, it has nuclear applications, and is a catalyst in petroleum refining. Discovered in 1778 by Carl Welhelm Scheele of Sweden. Impure metal was prepared in 1782 by Peter Jacob Hjelm. The name comes from the Greek word molybdos which means lead. Trace amounts of molybdenum are required for all known forms of life. All molybdenum compounds should be considered highly toxic, and will also cause severe birth defects.
Atomic Number42
Atomic Weight95.95
Mass Number98
Group6
Period5
Blockd
Protons42 p+
Neutrons56 n0
Electrons42 e-
Animated Bohr Model of Mo (Molybdenum)

Properties

Atomic Radius
145 pm
Molar Volume
Covalent Radius
138 pm
Metallic Radius
130 pm
Ionic Radius
69 pm
Crystal Radius
83 pm
Van der Waals Radius
217 pm
Density
10.2 g/cm³
Energy
Proton Affinity
Electron Affinity
Ionization Energy
7.09243 eV/particle
Ionization Energies of Mo (Molybdenum)
Heat of Vaporization
590 kJ/mol
Heat of Fusion
Heat of Formation
658.98 kJ/mol
Electrons
Electron Shells2, 8, 18, 13, 1
Bohr Model: Mo (Molybdenum)
Valence Electrons1
Electron Configuration[Kr] 4d5 5s1
Enhanced Bohr Model of Mo (Molybdenum)
Orbital Diagram of Mo (Molybdenum)
Oxidation States-4, -2, -1, 0, 1, 2, 3, 4, 5, 6
Electronegativity
2.16
Electrophilicity
1.2111478608972754 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
4,912.15 K
Melting Point
2,895.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Gray
Appearancegray metallic
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
0.0000048 1/K
Molar Heat Capacity
24.06 J/(mol K)
Specific Heat Capacity
0.251 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
20 MS/m
Electrical Resistivity
0.00000004999999999997 m Ω
Superconducting Point
0.915 K
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.0000000117 m³/Kg
Magnetic Susceptibility (Molar)
0.000000001122 m³/mol
Magnetic Susceptibility (Volume)
0.0001203
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal StructureBody Centered Cubic (BCC)
Lattice Constant
3.15 Å
Lattice Anglesπ/2, π/2, π/2
Mechanical Properties
Hardness
5.5 MPa
Bulk Modulus
230 GPa
Shear Modulus
120 GPa
Young Modulus
329 GPa
Poisson Ratio
0.31
Speed of Sound
6,190 m/s
Classification
CategoryTransition metals, Transition metals
CAS GroupVIA
IUPAC GroupVIB
Glawe Number56
Mendeleev Number52
Pettifor Number55
Geochemical Class
Goldschmidt Classsiderophile
Other
Gas Basicity
Dipole Polarizability
87 ± 6 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
2.6
Neutron Mass Absorption
0.0009
Quantum Numbers7S3
Space Group229 (Im_3m)

Isotopes of Molybdenum

Stable Isotopes7
Unstable Isotopes32
Radioactive Isotopes33

81Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
80.966226 ± 0.000537 Da
Mass Number81
G-Factor
Half Life
Spin5/2
Quadrupole Moment
Discovery Year2013
Parity+

81Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

82Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
81.956661 ± 0.000429 Da
Mass Number82
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year2013
Parity+

82Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

83Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
82.950252 ± 0.00043 Da
Mass Number83
G-Factor
Half Life
23 ± 19 ms
Spin3/2
Quadrupole Moment
Discovery Year1999
Parity-

83Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

84Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
83.941846 ± 0.00032 Da
Mass Number84
G-Factor
0
Half Life
2.3 ± 0.3 s
Spin0
Quadrupole Moment
0
Discovery Year1991
Parity+

84Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

85Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
84.938260736 ± 0.000017 Da
Mass Number85
G-Factor
Half Life
3.2 ± 0.2 s
Spin1/2
Quadrupole Moment
0
Discovery Year1992
Parity+

85Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)0.14%

86Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
85.931174092 ± 0.000003147 Da
Mass Number86
G-Factor
0
Half Life
19.1 ± 0.3 s
Spin0
Quadrupole Moment
0
Discovery Year1991
Parity+

86Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

87Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
86.928196198 ± 0.000003067 Da
Mass Number87
G-Factor
Half Life
14.1 ± 0.3 s
Spin7/2
Quadrupole Moment
Discovery Year1977
Parity+

87Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)15%

88Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
87.921967779 ± 0.0000041 Da
Mass Number88
G-Factor
0
Half Life
8 ± 0.2 m
Spin0
Quadrupole Moment
0
Discovery Year1971
Parity+

88Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

89Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
88.919468149 ± 0.0000042 Da
Mass Number89
G-Factor
Half Life
2.11 ± 0.1 m
Spin9/2
Quadrupole Moment
Discovery Year1980
Parity+

89Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

90Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
89.91393127 ± 0.000003717 Da
Mass Number90
G-Factor
0
Half Life
5.56 ± 0.09 h
Spin0
Quadrupole Moment
0
Discovery Year1953
Parity+

90Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

91Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
90.91174519 ± 0.000006696 Da
Mass Number91
G-Factor
-0.20688888888889 ± 0.00066666666666667
Half Life
15.49 ± 0.01 m
Spin9/2
Quadrupole Moment
Discovery Year1948
Parity+

91Mo Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

92Mo

Abundance
14.649 ± 0.106
Relative Atomic Mass
91.906807153 ± 0.000000168 Da
Mass Number92
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1930
Parity+

92Mo Decay Modes
Decay ModeIntensity
+ (double β+ decay)%

93Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
92.906808772 ± 0.000000193 Da
Mass Number93
G-Factor
Half Life
4 ± 0.8 ky
Spin5/2
Quadrupole Moment
Discovery Year1946
Parity+

93Mo Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

94Mo

Abundance
9.187 ± 0.033
Relative Atomic Mass
93.905083586 ± 0.000000151 Da
Mass Number94
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1930
Parity+

95Mo

Abundance
15.873 ± 0.03
Relative Atomic Mass
94.905837436 ± 0.000000132 Da
Mass Number95
G-Factor
Half Life
Spin5/2
Quadrupole Moment
-0.022 ± 0.001
Discovery Year1930
Parity+

96Mo

Abundance
16.673 ± 0.008
Relative Atomic Mass
95.90467477 ± 0.000000128 Da
Mass Number96
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1930
Parity+

97Mo

Abundance
9.582 ± 0.015
Relative Atomic Mass
96.906016903 ± 0.000000176 Da
Mass Number97
G-Factor
Half Life
Spin5/2
Quadrupole Moment
0.255 ± 0.013
Discovery Year1930
Parity+

98Mo

Abundance
24.292 ± 0.08
Relative Atomic Mass
97.905403609 ± 0.000000186 Da
Mass Number98
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1930
Parity+

98Mo Decay Modes
Decay ModeIntensity
(double β decay)%

99Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
98.907707299 ± 0.000000245 Da
Mass Number99
G-Factor
0.75 ± 0.006
Half Life
65.932 ± 0.005 h
Spin1/2
Quadrupole Moment
0
Discovery Year1948
Parity+

99Mo Decay Modes
Decay ModeIntensity
β (β decay)100%

100Mo

AbundanceRadioactive ☢️
9.744 ± 0.065
Relative Atomic Mass
99.907467982 ± 0.000000322 Da
Mass Number100
G-Factor
0
Half Life
7.07 ± 0.14 Ey
Spin0
Quadrupole Moment
0
Discovery Year1930
Parity+

100Mo Decay Modes
Decay ModeIntensity
(double β decay)100%

101Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
100.910337648 ± 0.000000331 Da
Mass Number101
G-Factor
Half Life
14.61 ± 0.03 m
Spin1/2
Quadrupole Moment
0
Discovery Year1941
Parity+

101Mo Decay Modes
Decay ModeIntensity
β (β decay)100%

102Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
101.910293725 ± 0.000008916 Da
Mass Number102
G-Factor
0
Half Life
11.3 ± 0.2 m
Spin0
Quadrupole Moment
0
Discovery Year1954
Parity+

102Mo Decay Modes
Decay ModeIntensity
β (β decay)100%

103Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
102.913091954 ± 0.0000099 Da
Mass Number103
G-Factor
-0.18 ± 0.013333333333333
Half Life
67.5 ± 1.5 s
Spin3/2
Quadrupole Moment
Discovery Year1963
Parity+

103Mo Decay Modes
Decay ModeIntensity
β (β decay)100%

104Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
103.913747443 ± 0.000009566 Da
Mass Number104
G-Factor
0
Half Life
60 ± 2 s
Spin0
Quadrupole Moment
0
Discovery Year1962
Parity+

104Mo Decay Modes
Decay ModeIntensity
β (β decay)100%

105Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
104.916981989 ± 0.000009721 Da
Mass Number105
G-Factor
-0.22 ± 0.008
Half Life
36.3 ± 0.8 s
Spin5/2
Quadrupole Moment
Discovery Year1962
Parity-

105Mo Decay Modes
Decay ModeIntensity
β (β decay)100%

106Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
105.918273231 ± 0.000009801 Da
Mass Number106
G-Factor
0
Half Life
8.73 ± 0.12 s
Spin0
Quadrupole Moment
0
Discovery Year1969
Parity+

106Mo Decay Modes
Decay ModeIntensity
β (β decay)100%

107Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
106.92211977 ± 0.000009901 Da
Mass Number107
G-Factor
Half Life
3.5 ± 0.5 s
Spin1/2
Quadrupole Moment
0
Discovery Year1972
Parity+

107Mo Decay Modes
Decay ModeIntensity
β (β decay)100%

108Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
107.924047508 ± 0.000009901 Da
Mass Number108
G-Factor
0
Half Life
1.105 ± 0.01 s
Spin0
Quadrupole Moment
0
Discovery Year1972
Parity+

108Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)0.5%

109Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
108.928438318 ± 0.000012 Da
Mass Number109
G-Factor
Half Life
700 ± 14 ms
Spin1/2
Quadrupole Moment
0
Discovery Year1992
Parity+

109Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)1.3%

110Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
109.930717956 ± 0.000026 Da
Mass Number110
G-Factor
0
Half Life
292 ± 7 ms
Spin0
Quadrupole Moment
0
Discovery Year1992
Parity+

110Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)2%

111Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
110.935651966 ± 0.000013503 Da
Mass Number111
G-Factor
Half Life
193.6 ± 4.4 ms
Spin1/2
Quadrupole Moment
0
Discovery Year1994
Parity+

111Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)12%

112Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
111.938293 ± 0.000215 Da
Mass Number112
G-Factor
0
Half Life
125 ± 5 ms
Spin0
Quadrupole Moment
0
Discovery Year1994
Parity+

112Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

113Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
112.943478 ± 0.000322 Da
Mass Number113
G-Factor
Half Life
80 ± 2 ms
Spin5/2
Quadrupole Moment
Discovery Year1994
Parity+

113Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

114Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
113.946666 ± 0.000322 Da
Mass Number114
G-Factor
0
Half Life
58 ± 2 ms
Spin0
Quadrupole Moment
0
Discovery Year1997
Parity+

114Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

115Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
114.952174 ± 0.000429 Da
Mass Number115
G-Factor
Half Life
45.5 ± 2 ms
Spin3/2
Quadrupole Moment
Discovery Year2010
Parity+

115Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

116Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
115.955759 ± 0.000537 Da
Mass Number116
G-Factor
0
Half Life
32 ± 4 ms
Spin0
Quadrupole Moment
0
Discovery Year2010
Parity+

116Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

117Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
116.961686 ± 0.000537 Da
Mass Number117
G-Factor
Half Life
22 ± 5 ms
Spin3/2
Quadrupole Moment
Discovery Year2010
Parity+

117Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

118Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
117.965249 ± 0.000537 Da
Mass Number118
G-Factor
0
Half Life
21 ± 6 ms
Spin0
Quadrupole Moment
0
Discovery Year2015
Parity+

118Mo Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%

119Mo

AbundanceRadioactive ☢️
Relative Atomic Mass
118.971465 ± 0.000322 Da
Mass Number119
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year2018
Parity+

119Mo Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%
2n (2-neutron emission)%
Molybdenum crystaline fragment and 1cm3 cube.jpg

History

Molybdenite was often confused for graphite and it was thought to contain lead. In 1778 Swedish scientist Carl Wilhelm Scheele proved that molybdenite was not graphite nor did it contain lead. In 1781, Scheele's friend and countryman, Peter J. Hjelm isolated the metal by using carbon and linseed oil. From the Greek word molybdo, lead

DiscoverersCarl Wilhelm Scheele
Discovery LocationSweden
Discovery Year1778
Etymology (Name Origin)Greek: molybdos (lead).
Pronunciationmeh-LIB-deh-nem (English)
Molybdenum is toxic in all but small quantities
Molybdenum is essential for plant foliage health

Uses

Molybdenum is used as glass furnace electrodes due to its high melting point. The metal is also used in nuclear energy applications and for missile and aircraft parts. Molybdenum is valuable as a catalyst in the refining of petroleum. Molybdenum is used in small quantities to harden steel and is used in many alloys. Its alloys are used in aircraft, missiles, and protective coatings in boiler plate.

Sources

Found in the minerals molybdenite (MoS2) and wulfenite (MoO4Pb).

Abundance
Abundance in Earth's crust
1.2 mg/kg
Abundance in Oceans
0.01 mg/L
Abundance in Human Body
0.00001 %
Abundance in Meteor
0.00012 %
Abundance in Sun
0.0000009 %
Abundance in Universe
0.0000005 %

Nuclear Screening Constants

1s0.8744
2p4.0282
2s11.1232
3d14.7717
3p16.5264
3s16.0185
4d30.6076
4p27.0232
4s25.9036
5s35.894