Terbium

Terbium (Tb)

Silvery metallic element belonging to the lanthanoids. Tb-159 is the only stable isotope, there are seventeen artificial isotopes. Discovered by G.G. Mosander in 1843.
Atomic Number65
Atomic Weight158.92535
Mass Number159
Group
Period6
Blockf
Protons65 p+
Neutrons94 n0
Electrons65 e-
Terbium element.jpg Animated Bohr Model of Tb (Terbium) Enhanced Bohr Model of Tb (Terbium) Bohr Model: Tb (Terbium) Orbital Diagram of Tb (Terbium)

Properties

Atomic Radius
175 pm
Molar Volume
Covalent Radius
168 pm
Metallic Radius
Ionic Radius
92.3 pm
Crystal Radius
106.3 pm
Van der Waals Radius
233 pm
Density
8.23 g/cm³
Energy
Proton Affinity
Electron Affinity
Ionization Energy
Heat of Vaporization
389 kJ/mol
Heat of Fusion
Heat of Formation
388.7 kJ/mol
Electrons
Electron Shells2, 8, 18, 27, 8, 2
Valence Electrons3
Electron Configuration[Xe] 4f9 6s2
Oxidation States0, 1, 2, 3, 4
Electronegativity
Electrophilicity
1.3142725121307568 eV/particle
Phases
PhaseSolid
Gas Phase
Boiling Point
3,503.15 K
Melting Point
1,632.15 K
Critical Pressure
Critical Temperature
Triple Point
Visual
Color
Silver
Appearancesilvery white
Refractive Index
Thermodynamic Properties
Thermal Conductivity
11.1 W/(m K)
Thermal Expansion
0.0000103 1/K
Molar Heat Capacity
28.91 J/(mol K)
Specific Heat Capacity
0.182 J/(g⋅K)
Heat Capacity Ratio (Adiabatic Index)
Electrical Properties
TypeConductor
Electrical Conductivity
0.83 MS/m
Electrical Resistivity
0.0000012 m Ω
Superconducting Point
Magnetism
Typeparamagnetic
Magnetic Susceptibility (Mass)
0.0000136 m³/Kg
Magnetic Susceptibility (Molar)
0.000002161385 m³/mol
Magnetic Susceptibility (Volume)
0.1117784
Magnetic Ordering
Curie Point
222 K
Neel Point
230 K
Structure
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
3.6 Å
Lattice Anglesπ/2, π/2, 2 π/3
Mechanical Properties
Hardness
Bulk Modulus
38.7 GPa
Shear Modulus
22 GPa
Young Modulus
56 GPa
Poisson Ratio
0.26
Speed of Sound
2,620 m/s
Classification
CategoryLanthanides, Lanthanides
CAS Group
IUPAC Group
Glawe Number25
Mendeleev Number29
Pettifor Number26
Geochemical Classrare earth & related
Goldschmidt Classlitophile
Other
Gas Basicity
Dipole Polarizability
170 ± 20 a₀
C6 Dispersion Coefficient
Allotropes
Neutron Cross Section
23
Neutron Mass Absorption
0.009
Quantum Numbers6H15/2
Space Group194 (P63/mmc)

Isotopes of Terbium

Stable Isotopes1
Unstable Isotopes39
Radioactive Isotopes39

135Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
134.964516 ± 0.000429 Da
Mass Number135
G-Factor
Half Life
1.01 ± 0.28 ms
Spin7/2
Quadrupole Moment
Discovery Year2004
Parity-

135Tb Decay Modes
Decay ModeIntensity
p (proton emission)100%
β+ (β+ decay; β+ = ϵ + e+)%

136Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
135.96146 ± 0.000537 Da
Mass Number136
G-Factor
Half Life
Spin5
Quadrupole Moment
Discovery Year
Parity-

136Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%

137Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
136.95602 ± 0.00043 Da
Mass Number137
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year
Parity+

137Tb Decay Modes
Decay ModeIntensity
p (proton emission)%
β+ (β+ decay; β+ = ϵ + e+)%

138Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
137.953193 ± 0.000322 Da
Mass Number138
G-Factor
Half Life
Spin2
Quadrupole Moment
Discovery Year1993
Parity+

138Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)%
β+ p (β+-delayed proton emission)%
p (proton emission)0%

139Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
138.94833 ± 0.00032 Da
Mass Number139
G-Factor
Half Life
1.6 ± 0.2 s
Spin5/2
Quadrupole Moment
Discovery Year1999
Parity-

139Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β+ p (β+-delayed proton emission)%

140Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
139.945805048 ± 0.000859359 Da
Mass Number140
G-Factor
Half Life
2.29 ± 0.15 s
Spin7
Quadrupole Moment
Discovery Year1986
Parity+

140Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
ϵ (electron capture)3%
β+ p (β+-delayed proton emission)0.26%

141Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
140.941448 ± 0.000113 Da
Mass Number141
G-Factor
Half Life
3.5 ± 0.2 s
Spin5/2
Quadrupole Moment
Discovery Year1986
Parity-

141Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

142Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
141.939280858 ± 0.000752079 Da
Mass Number142
G-Factor
Half Life
597 ± 17 ms
Spin1
Quadrupole Moment
Discovery Year1991
Parity+

142Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
e+ (positron emission)96.8%
ϵ (electron capture)3.2%
β+ p (β+-delayed proton emission)0.0022%

143Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
142.935137332 ± 0.000055 Da
Mass Number143
G-Factor
Half Life
12 ± 1 s
Spin11/2
Quadrupole Moment
Discovery Year1985
Parity-

143Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

144Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
143.933045 ± 0.00003 Da
Mass Number144
G-Factor
Half Life
Spin1
Quadrupole Moment
Discovery Year1982
Parity+

144Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

145Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
144.928717001 ± 0.000119051 Da
Mass Number145
G-Factor
Half Life
30.9 ± 0.6 s
Spin11/2
Quadrupole Moment
Discovery Year1981
Parity-

145Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

146Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
145.927252739 ± 0.000048159 Da
Mass Number146
G-Factor
Half Life
8 ± 4 s
Spin1
Quadrupole Moment
Discovery Year1974
Parity+

146Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

147Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
146.92405462 ± 0.000008691 Da
Mass Number147
G-Factor
3.42 ± 0.1
Half Life
1.64 ± 0.03 h
Spin1/2
Quadrupole Moment
0
Discovery Year1969
Parity+

147Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

148Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
147.924275476 ± 0.000013379 Da
Mass Number148
G-Factor
-0.88 ± 0.01
Half Life
60 ± 1 m
Spin2
Quadrupole Moment
-0.3 ± 0.2
Discovery Year1960
Parity-

148Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

149Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
148.923253792 ± 0.000003895 Da
Mass Number149
G-Factor
2.72 ± 0.04
Half Life
4.118 ± 0.025 h
Spin1/2
Quadrupole Moment
0
Discovery Year1950
Parity+

149Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)83.3%
α (α emission)16.7%

150Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
149.923664799 ± 0.000007912 Da
Mass Number150
G-Factor
-0.45 ± 0.01
Half Life
3.48 ± 0.16 h
Spin2
Quadrupole Moment
Discovery Year1959
Parity

150Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)%

151Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
150.92310897 ± 0.000004395 Da
Mass Number151
G-Factor
1.852 ± 0.012
Half Life
17.609 ± 0.001 h
Spin1/2
Quadrupole Moment
0
Discovery Year1953
Parity+

151Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)99.9905%
α (α emission)0.0095%

152Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
151.924081855 ± 0.000042955 Da
Mass Number152
G-Factor
-0.29 ± 0.01
Half Life
17.5 ± 0.1 h
Spin2
Quadrupole Moment
0.34 ± 0.13
Discovery Year1959
Parity-

152Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
α (α emission)%

153Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
152.923441694 ± 0.000004237 Da
Mass Number153
G-Factor
1.388 ± 0.008
Half Life
2.34 ± 0.01 d
Spin5/2
Quadrupole Moment
1.08 ± 0.14
Discovery Year1957
Parity+

153Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%

154Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
153.924683681 ± 0.000048641 Da
Mass Number154
G-Factor
Half Life
9.994 ± 0.039 h
Spin3
Quadrupole Moment
Discovery Year1972
Parity-

154Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β (β decay)%

155Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
154.923509511 ± 0.000010552 Da
Mass Number155
G-Factor
1.3533333333333 ± 0.013333333333333
Half Life
5.32 ± 0.06 d
Spin3/2
Quadrupole Moment
1.41 ± 0.06
Discovery Year1957
Parity+

155Tb Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

156Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
155.924754209 ± 0.000004044 Da
Mass Number156
G-Factor
0.56666666666667 ± 0.066666666666667
Half Life
5.35 ± 0.1 d
Spin3
Quadrupole Moment
2.3 ± 0.8
Discovery Year1950
Parity-

156Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)100%
β (β decay)%

157Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
156.924031888 ± 0.000001092 Da
Mass Number157
G-Factor
1.3533333333333 ± 0.013333333333333
Half Life
71 ± 7 y
Spin3/2
Quadrupole Moment
1.4 ± 0.08
Discovery Year1960
Parity+

157Tb Decay Modes
Decay ModeIntensity
ϵ (electron capture)100%

158Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
157.925419942 ± 0.00000136 Da
Mass Number158
G-Factor
0.58433333333333 ± 0.0023333333333333
Half Life
180 ± 11 y
Spin3
Quadrupole Moment
Discovery Year1957
Parity-

158Tb Decay Modes
Decay ModeIntensity
β+ (β+ decay; β+ = ϵ + e+)83.4%
β (β decay)16.6%

159Tb

Abundance
100
Relative Atomic Mass
158.925353707 ± 0.000001184 Da
Mass Number159
G-Factor
1.3393333333333 ± 0.0026666666666667
Half Life
Spin3/2
Quadrupole Moment
1.432 ± 0.008
Discovery Year1933
Parity+

160Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
159.927174553 ± 0.000001191 Da
Mass Number160
G-Factor
0.566 ± 0.0026666666666667
Half Life
72.3 ± 0.2 d
Spin3
Quadrupole Moment
3.85 ± 0.05
Discovery Year1943
Parity-

160Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

161Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
160.927576806 ± 0.000001308 Da
Mass Number161
G-Factor
1.4666666666667 ± 0.066666666666667
Half Life
6.948 ± 0.005 d
Spin3/2
Quadrupole Moment
1.3 ± 0.6
Discovery Year1949
Parity+

161Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

162Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
161.9292754 ± 0.0000022 Da
Mass Number162
G-Factor
Half Life
7.6 ± 0.15 m
Spin1
Quadrupole Moment
Discovery Year1965
Parity-

162Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

163Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
162.930653609 ± 0.000004358 Da
Mass Number163
G-Factor
Half Life
19.5 ± 0.3 m
Spin3/2
Quadrupole Moment
Discovery Year1966
Parity+

163Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

164Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
163.933327561 ± 0.000002 Da
Mass Number164
G-Factor
Half Life
3 ± 0.1 m
Spin5
Quadrupole Moment
Discovery Year1968
Parity+

164Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

165Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
164.934955198 ± 0.000001654 Da
Mass Number165
G-Factor
Half Life
2.11 ± 0.1 m
Spin3/2
Quadrupole Moment
Discovery Year1983
Parity+

165Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

166Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
165.937939727 ± 0.00000157 Da
Mass Number166
G-Factor
Half Life
27.1 ± 1.5 s
Spin1
Quadrupole Moment
Discovery Year1996
Parity-

166Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

167Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
166.940007046 ± 0.000002071 Da
Mass Number167
G-Factor
Half Life
18.9 ± 1.6 s
Spin3/2
Quadrupole Moment
Discovery Year1999
Parity+

167Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

168Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
167.943337074 ± 0.0000045 Da
Mass Number168
G-Factor
Half Life
9.4 ± 0.4 s
Spin4
Quadrupole Moment
Discovery Year1999
Parity-

168Tb Decay Modes
Decay ModeIntensity
β (β decay)100%

169Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
168.945807 ± 0.000322 Da
Mass Number169
G-Factor
Half Life
5.13 ± 0.32 s
Spin3/2
Quadrupole Moment
Discovery Year2012
Parity+

169Tb Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

170Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
169.949855 ± 0.000322 Da
Mass Number170
G-Factor
Half Life
960 ± 78 ms
Spin2
Quadrupole Moment
Discovery Year2012
Parity-

170Tb Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

171Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
170.953011 ± 0.000429 Da
Mass Number171
G-Factor
Half Life
1.23 ± 0.1 s
Spin3/2
Quadrupole Moment
Discovery Year2012
Parity+

171Tb Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

172Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
171.957391 ± 0.000537 Da
Mass Number172
G-Factor
Half Life
760 ± 190 ms
Spin6
Quadrupole Moment
Discovery Year2012
Parity+

172Tb Decay Modes
Decay ModeIntensity
β (β decay)100%
β n (β-delayed neutron emission)%

173Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
172.960805 ± 0.000537 Da
Mass Number173
G-Factor
Half Life
Spin3/2
Quadrupole Moment
Discovery Year2018
Parity+

173Tb Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

174Tb

AbundanceRadioactive ☢️
Relative Atomic Mass
173.965679 ± 0.000537 Da
Mass Number174
G-Factor
Half Life
Spin2
Quadrupole Moment
Discovery Year2018
Parity-

174Tb Decay Modes
Decay ModeIntensity
β (β decay)%
β n (β-delayed neutron emission)%

History

Terbium was discovered in 1843 by Swedish chemist Carl Gustaf Mosander, who detected it as an impurity in yttria. Using ammonium hydroxide he precipitated fractions of different basicity from yttria. In these fractions he found that the fraction that was essentially colorless in solution, but gave a brown-tinged oxide was terbium. Terbium was named after Ytterby, a town in Sweden

DiscoverersCarl Mosander
Discovery LocationSweden
Discovery Year1843
Etymology (Name Origin)Named after Ytterby, a village in Sweden.
PronunciationTUR-bi-em (English)
Terbium is considered to be moderately toxic
Terbium is soft enough to be cut with a knife

Uses

Terbium is used in alloys and in the production of electronic devices. It is also used as a dopant for materials in solid-state devices and optical fibers. Terbium oxide is in fluorescent lamps and TV tubes. The brilliant fluorescence allows terbium to be used as a probe in biochemistry. It is used in modest amounts in special lasers and solid-state devices.

Sources

Found with other rare earths in monazite sand, which typically contain 0.03% terbium. Other sources are xenotime and euxenite, both of which are oxide mixtures that can contain up to 1% terbium.

Abundance
Abundance in Earth's crust
1.2 mg/kg
Abundance in Oceans
0.00000014 mg/L
Abundance in Human Body
Abundance in Meteor
0.0000039 %
Abundance in Sun
0.00000001 %
Abundance in Universe
0.00000005 %

Nuclear Screening Constants

1s1.2739
2p4.3076
2s17.0278
3d13.7015
3p19.9853
3s20.4485
4d34.69
4f39.1352
4p31.6012
4s30.98
5p48.039
5s45.8295
6s56.6996