Hafnium

Hafnium (Hf)

Silvery lustrous metallic transition element. Used in tungsten alloys in filaments and electrodes, also acts as a neutron absorber. First reported by Urbain in 1911, existence was finally established in 1923 by D. Coster, G.C. de Hevesy in 1923.
Atomic Number72
Atomic Weight178.49
Mass Number180
Group4
Period6
Blockd
Protons72 p+
Neutrons108 n0
Electrons72 e-
Hf-crystal bar.jpg Animated Bohr Model of Hf (Hafnium) Enhanced Bohr Model of Hf (Hafnium) Bohr Model: Hf (Hafnium) Orbital Diagram of Hf (Hafnium)

Properties

Atomic Radius
155 pm
Molar Volume
Covalent Radius
152 pm
Metallic Radius
144 pm
Ionic Radius
58 pm
Crystal Radius
72 pm
Van der Waals Radius
223 pm
Density
13.3 g/cm³
Energy
Proton Affinity
Electron Affinity
Ionization Energy
6.82507 eV/particle
Heat of Vaporization
575 kJ/mol
Heat of Fusion
25.1 kJ/mol
Heat of Formation
618.4 kJ/mol
Electrons
Electron Shells2, 8, 18, 32, 10, 2
Valence Electrons4
Electron Configuration[Xe] 4f14 5d2 6s2
Oxidation States-2, 0, 1, 2, 3, 4
Electronegativity
1.3
Electrophilicity
0.8583981383413326 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
4,873.15 K
Melting Point
2,506.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Gray
Appearancesteel gray
Refractive Index
Thermodynamic Properties
Thermal Conductivity
Thermal Expansion
0.0000059 1/K
Molar Heat Capacity
25.73 J/(mol K)
Specific Heat Capacity
0.144 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
3.3 MS/m
Electrical Resistivity
0.0000003 m Ω
Superconducting Point
0.128 K
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.0000000053 m³/Kg
Magnetic Susceptibility (Molar)
0.000000000946 m³/mol
Magnetic Susceptibility (Volume)
0.0000705
Magnetic Ordering
Curie Point
Neel Point
Structure
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
3.2 Å
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
5.5 MPa
Bulk Modulus
110 GPa
Shear Modulus
30 GPa
Young Modulus
78 GPa
Poisson Ratio
0.37
Speed of Sound
3,010 m/s
Classification
CategoryTransition metals, Transition metals
CAS GroupIVA
IUPAC GroupIVB
Glawe Number50
Mendeleev Number45
Pettifor Number50
Geochemical Classhigh field strength
Goldschmidt Classlitophile
Other
Gas Basicity
Dipole Polarizability
103 ± 6 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
104
Neutron Mass Absorption
0.02
Quantum Numbers3F2
Space Group194 (P63/mmc)

Isotopes of Hafnium

Stable Isotopes6
Unstable Isotopes32
Radioactive Isotopes33

153Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
152.970692 ± 0.000322 Da
Mass Number153
G-Factor
Half Life
Spin1/2
Quadrupole Moment
0
Discovery Year2000
Parity+

153Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%

154Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
153.964863 ± 0.000322 Da
Mass Number154
G-Factor
0
Half Life
2 ± 1 s
Spin0
Quadrupole Moment
0
Discovery Year1981
Parity+

154Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)0%

155Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
154.963167 ± 0.000322 Da
Mass Number155
G-Factor
Half Life
843 ± 30 ms
Spin7/2
Quadrupole Moment
Discovery Year1981
Parity-

155Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)%

156Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
155.959399083 ± 0.000160752 Da
Mass Number156
G-Factor
0
Half Life
23 ± 1 ms
Spin0
Quadrupole Moment
0
Discovery Year1979
Parity+

156Hf Decay Modes
Decay ModeIntensity
α (α emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

157Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
156.958288 ± 0.000215 Da
Mass Number157
G-Factor
Half Life
115 ± 1 ms
Spin7/2
Quadrupole Moment
Discovery Year1965
Parity-

157Hf Decay Modes
Decay ModeIntensity
α (α emission)94%
β+ (β+ decay; β+ = ϵ + e+)14%

158Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
157.954801217 ± 0.00001878 Da
Mass Number158
G-Factor
0
Half Life
2.85 ± 0.07 s
Spin0
Quadrupole Moment
0
Discovery Year1965
Parity+

158Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)55.7%
α (α emission)44.3%

159Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
158.953995837 ± 0.000018049 Da
Mass Number159
G-Factor
Half Life
5.2 ± 0.1 s
Spin7/2
Quadrupole Moment
Discovery Year1973
Parity-

159Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)65%
α (α emission)35%

160Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
159.950682728 ± 0.000010241 Da
Mass Number160
G-Factor
0
Half Life
13.6 ± 0.2 s
Spin0
Quadrupole Moment
0
Discovery Year1973
Parity+

160Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.3%
α (α emission)0.7%

161Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
160.950277927 ± 0.000025174 Da
Mass Number161
G-Factor
Half Life
18.4 ± 0.4 s
Spin7/2
Quadrupole Moment
Discovery Year1973
Parity-

161Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.71%
α (α emission)0.29%

162Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
161.947215526 ± 0.00000961 Da
Mass Number162
G-Factor
0
Half Life
39.4 ± 0.9 s
Spin0
Quadrupole Moment
0
Discovery Year1982
Parity+

162Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.992%
α (α emission)0.008%

163Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
162.947107211 ± 0.000027582 Da
Mass Number163
G-Factor
Half Life
40 ± 0.6 s
Spin5/2
Quadrupole Moment
Discovery Year1982
Parity-

163Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)%

164Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
163.944370709 ± 0.000016975 Da
Mass Number164
G-Factor
0
Half Life
111 ± 8 s
Spin0
Quadrupole Moment
0
Discovery Year1981
Parity+

164Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

165Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
164.944567 ± 0.00003 Da
Mass Number165
G-Factor
Half Life
76 ± 4 s
Spin5/2
Quadrupole Moment
Discovery Year1981
Parity-

165Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

166Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
165.94218 ± 0.00003 Da
Mass Number166
G-Factor
0
Half Life
6.77 ± 0.3 m
Spin0
Quadrupole Moment
0
Discovery Year1965
Parity+

166Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

167Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
166.9426 ± 0.00003 Da
Mass Number167
G-Factor
Half Life
2.05 ± 0.05 m
Spin5/2
Quadrupole Moment
Discovery Year1969
Parity

167Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

168Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
167.940568 ± 0.00003 Da
Mass Number168
G-Factor
0
Half Life
25.95 ± 0.2 m
Spin0
Quadrupole Moment
0
Discovery Year1961
Parity+

168Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
ϵ (electron capture)98%
e+ (positron emission)2%

169Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
168.941259 ± 0.00003 Da
Mass Number169
G-Factor
Half Life
3.24 ± 0.04 m
Spin5/2
Quadrupole Moment
Discovery Year1969
Parity-

169Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

170Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
169.939609 ± 0.00003 Da
Mass Number170
G-Factor
0
Half Life
16.01 ± 0.13 h
Spin0
Quadrupole Moment
0
Discovery Year1961
Parity+

170Hf Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

171Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
170.940492 ± 0.000031 Da
Mass Number171
G-Factor
-0.19257142857143 ± 0.0034285714285714
Half Life
12.1 ± 0.4 h
Spin7/2
Quadrupole Moment
3.46 ± 0.03
Discovery Year1951
Parity+

171Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

172Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
171.939449716 ± 0.000026224 Da
Mass Number172
G-Factor
0
Half Life
1.87 ± 0.03 y
Spin0
Quadrupole Moment
0
Discovery Year1951
Parity+

172Hf Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

173Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
172.940513 ± 0.00003 Da
Mass Number173
G-Factor
1.004 ± 0.014
Half Life
23.6 ± 0.1 h
Spin1/2
Quadrupole Moment
0
Discovery Year1951
Parity-

173Hf Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

174Hf

AbundanceRadioactive ☢️
0.16 ± 0.12
Relative Atomic Mass
173.940048377 ± 0.000002425 Da
Mass Number174
G-Factor
0
Half Life
2 ± 0.4 Py
Spin0
Quadrupole Moment
0
Discovery Year1939
Parity+

174Hf Decay Modes
Decay ModeIntensity
α (α emission)100%
+ (double β+ decay)%

175Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
174.941511424 ± 0.00000245 Da
Mass Number175
G-Factor
-0.2708 ± 0.0036
Half Life
70.65 ± 0.19 d
Spin5/2
Quadrupole Moment
2.72 ± 0.02
Discovery Year1949
Parity-

175Hf Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

176Hf

Abundance
5.26 ± 0.7
Relative Atomic Mass
175.941409797 ± 0.000001591 Da
Mass Number176
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1934
Parity+

177Hf

Abundance
18.6 ± 0.16
Relative Atomic Mass
176.943230187 ± 0.000001514 Da
Mass Number177
G-Factor
0.226 ± 0.00025714285714286
Half Life
Spin7/2
Quadrupole Moment
3.37 ± 0.03
Discovery Year1934
Parity-

178Hf

Abundance
27.28 ± 0.28
Relative Atomic Mass
177.943708322 ± 0.000001519 Da
Mass Number178
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1934
Parity+

179Hf

Abundance
13.62 ± 0.11
Relative Atomic Mass
178.945825705 ± 0.00000152 Da
Mass Number179
G-Factor
-0.14197777777778 ± 0.00031111111111111
Half Life
Spin9/2
Quadrupole Moment
3.79 ± 0.03
Discovery Year1934
Parity+

180Hf

Abundance
35.08 ± 0.33
Relative Atomic Mass
179.946559537 ± 0.000001525 Da
Mass Number180
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1934
Parity+

181Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
180.949110834 ± 0.000001527 Da
Mass Number181
G-Factor
Half Life
42.39 ± 0.06 d
Spin1/2
Quadrupole Moment
0
Discovery Year1935
Parity-

181Hf Decay Modes
Decay ModeIntensity
β (β decay)100%

182Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
181.950563684 ± 0.000006619 Da
Mass Number182
G-Factor
0
Half Life
8.9 ± 0.09 My
Spin0
Quadrupole Moment
0
Discovery Year1961
Parity+

182Hf Decay Modes
Decay ModeIntensity
β (β decay)100%

183Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
182.953533203 ± 0.000032251 Da
Mass Number183
G-Factor
Half Life
1.018 ± 0.002 h
Spin3/2
Quadrupole Moment
Discovery Year1956
Parity-

183Hf Decay Modes
Decay ModeIntensity
β (β decay)100%

184Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
183.955448507 ± 0.000042625 Da
Mass Number184
G-Factor
0
Half Life
4.12 ± 0.05 h
Spin0
Quadrupole Moment
0
Discovery Year1973
Parity+

184Hf Decay Modes
Decay ModeIntensity
β (β decay)100%

185Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
184.958862 ± 0.000069 Da
Mass Number185
G-Factor
Half Life
3.5 ± 0.6 m
Spin9/2
Quadrupole Moment
Discovery Year1993
Parity-

185Hf Decay Modes
Decay ModeIntensity
β (β decay)100%

186Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
185.960897 ± 0.000055 Da
Mass Number186
G-Factor
0
Half Life
2.6 ± 1.2 m
Spin0
Quadrupole Moment
0
Discovery Year1998
Parity+

186Hf Decay Modes
Decay ModeIntensity
β (β decay)100%

187Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
186.964573 ± 0.000215 Da
Mass Number187
G-Factor
Half Life
Spin9/2
Quadrupole Moment
Discovery Year1999
Parity-

187Hf Decay Modes
Decay ModeIntensity
β (β decay)%

188Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
187.966903 ± 0.000322 Da
Mass Number188
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year1999
Parity+

188Hf Decay Modes
Decay ModeIntensity
β (β decay)%

189Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
188.970853 ± 0.000322 Da
Mass Number189
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year2009
Parity-

189Hf Decay Modes
Decay ModeIntensity
β (β decay)100%

190Hf

AbundanceRadioactive ☢️
Relative Atomic Mass
189.973376 ± 0.000429 Da
Mass Number190
G-Factor
0
Half Life
Spin0
Quadrupole Moment
0
Discovery Year2012
Parity+

190Hf Decay Modes
Decay ModeIntensity
β (β decay)%

History

In 1911, Georges Urbain claimed to have found the element in rare-earth residues which was shown later to be a mixture of already discovered lanthanides. Dirk Coster and George de Hevesy found it by X-ray spectroscopic analysis in Norwegian zircon in 1922. Anton Eduard van Arkel and Jan Hendrik de Boer were the first to prepare metallic hafnium by passing hafnium tetra-iodide vapor over a heated tungsten filament in 1924. From Hafinia, the Latin name for Copenhagen

DiscoverersDirk Coster, Georg von Hevesy
Discovery LocationDenmark
Discovery Year1923
Etymology (Name Origin)From Hafnia, the Latin name of Copenhagen.
PronunciationHAF-ni-em (English)
Hafnium is considered to be non-toxic
In powdered form, hafnium is pyrophoric and can ignite spontaneously in air

Uses

Hafnium oxide-based compounds are being introduced into silicon-based chips to produce smaller, more energy efficient and performance packed processors. Most of the hafnium produced is used in the production of control rods for nuclear reactors. Hafnium is also used in photographic flash bulbs, light bulb filaments, and in electronic equipment as cathodes and capacitors. Used in reactor control rods because of its ability to absorb neutrons.

Sources

Obtained from mineral zircon or baddeleyite.

Abundance
Abundance in Earth's crust
Abundance in Oceans
0.000007 mg/L
Abundance in Human Body
Abundance in Meteor
0.000017 %
Abundance in Sun
0.0000001 %
Abundance in Universe
0.00000007 %

Nuclear Screening Constants

1s1.3984
2p4.4012
2s18.8102
3d13.5702
3p21.0168
3s21.6885
4d36.476
4f39.7904
4p34.0704
4s33.0228
5d55.3805
5p52.415
5s50.167
6s62.8356