Symbol
Tm
  
Tb
  
Group Number
Not Available
  
Not Available
  
Period Number
6
  
6
  
Block
f block
  
f block
  
Element Family
Lanthanide
  
Lanthanide
  
Space Group Name
P63/mmc
  
P63/mmc
  
Interesting Facts
- Thulium metal can resist corrosion due to dry air .
- Only Tm-169 isotope of Thulium metal occur naturally.
  
- At times Terbium metal acts same as Calcium.
- Terbium metal closely similar to Lanthanum metal.
  
Sources
Found in Minerals, Mining, Ores of Minerals
  
Found in Minerals, Found with Other Rare Earth Metals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
Per Teodor Cleve
  
Carl Gustaf Mosander
  
Discovery
In 1879
  
In 1842
  
Abundance
  
  
Abundance In Sun
~0.00000002 %
  
28
~0.00000001 %
  
29
Abundance In Earth's Crust
Uses & Benefits
- Thulium metal produces isotopes that emits X-rays. This isotope is used in X-ray machine.
-
Thulium element is also used in Surgical equipment like laser.
  
- Terbium salts are used in optical devices like laser devices.
-
Terbium’s alloy lengthens and shortens the magnetic field and this effect forms loudspeaker.
  
Industrial Uses
NA
  
Electronic Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys, Nuclear Research, Research Purposes
  
Alloys
  
Biological Properties
  
  
Toxicity
Unknown
  
Low Toxic
  
Present in Human Body
No
  
No
  
Melting Point
1,545.00 °C
  
23
1,356.00 °C
  
33
Boiling Point
1,730.00 °C
  
99+
3,123.00 °C
  
29
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery Gray
  
Silvery White
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Speed of Sound
Not Available
  
2,620.00 m/s
  
35
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Tm
  
Tb
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Not Available
  
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Not Available
  
Ionization Energies
  
  
1st Energy Level
596.70 kJ/mol
  
99+
603.40 kJ/mol
  
99+
2nd Energy Level
1,160.00 kJ/mol
  
99+
1,174.80 kJ/mol
  
99+
3rd Energy Level
2,285.00 kJ/mol
  
99+
2,417.00 kJ/mol
  
99+
4th Energy Level
4,120.00 kJ/mol
  
33
4,203.00 kJ/mol
  
31
Electrochemical Equivalent
2.10 g/amp-hr
  
26
1.98 g/amp-hr
  
31
Electron Work Function
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Xe] 4f13 6s2
  
[Xe] 4f9 6s2
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
HCP-Crystal-Structure-of-Thulium.jpg#100
  
HCP-Crystal-Structure-of-Terbium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Van der Waals Radius
Not Available
  
Atomic Weight
168.93 amu
  
99+
158.93 amu
  
99+
Atomic Volume
18.10 cm3/mol
  
28
19.20 cm3/mol
  
22
Adjacent Atomic Numbers
  
  
Valence Electron Potential
49.70 (-eV)
  
28
46.80 (-eV)
  
33
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, 2 π/3
  
Density
  
  
Density At Room Temperature
8.23 g/cm3
  
99+
Density When Liquid (at m.p.)
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 2000 K
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile, Malleable
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Electrical Conductivity
0.02 106/cm Ω
  
99+
0.01 106/cm Ω
  
99+
Electron Affinity
50.00 kJ/mol
  
21
50.00 kJ/mol
  
21
Specific Heat
0.16 J/(kg K)
  
35
0.18 J/(kg K)
  
33
Molar Heat Capacity
27.03 J/mol·K
  
22
28.91 J/mol·K
  
9
Thermal Conductivity
16.90 W/m·K
  
99+
11.10 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
13.30 µm/(m·K)
  
29
10.30 µm/(m·K)
  
38
Enthalpy
  
  
Enthalpy of Vaporization
191.00 kJ/mol
  
99+
330.90 kJ/mol
  
26
Enthalpy of Fusion
16.80 kJ/mol
  
17
10.80 kJ/mol
  
34
Enthalpy of Atomization
247.00 kJ/mol
  
99+
314.00 kJ/mol
  
33
Standard Molar Entropy
74.00 J/mol.K
  
9
73.20 J/mol.K
  
10