Symbol
Tb
  
Po
  
Group Number
Not Available
  
Period Number
6
  
6
  
Block
f block
  
p block
  
Element Family
Lanthanide
  
Post-Transition
  
Space Group Name
P63/mmc
  
Pm-3m
  
Interesting Facts
- At times Terbium metal acts same as Calcium.
- Terbium metal closely similar to Lanthanum metal.
  
- Polonium was the first radioactive element to be discovered.
- Polonium element and its compounds are highly radioactive.
- Its alloy with Beryllium provides source of neutrons.
  
Sources
Found in Minerals, Found with Other Rare Earth Metals, Mining, Ores of Minerals
  
Mining, Ores of metals
  
History
  
  
Who Discovered
Carl Gustaf Mosander
  
Pierre Curie and Marie Curie
  
Discovery
In 1842
  
In 1898
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~0.00000001 %
  
29
~-9999 %
  
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
Uses & Benefits
- Terbium salts are used in optical devices like laser devices.
-
Terbium’s alloy lengthens and shortens the magnetic field and this effect forms loudspeaker.
  
- Polonium metal has different Allotropes, it is used in antistatic devices and for research purpose.
- A 1 gram of Polonium can reach a temperature of 500°C, hence it is used as a heat source for space equipment.
  
Industrial Uses
Electronic Industry
  
Aerospace Industry, Ammunition Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
Low Toxic
  
Highly Toxic
  
Present in Human Body
No
  
No
  
In Blood
Not Available
  
0.00 Blood/mg dm-3
  
37
In Bone
Not Available
  
0.00 p.p.m.
  
36
Melting Point
1,356.00 °C
  
33
Boiling Point
3,123.00 °C
  
29
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery White
  
Silver
  
Luster
Metallic
  
NA
  
Hardness
  
  
Brinell Hardness
Not Available
  
Vickers Hardness
Not Available
  
Speed of Sound
2,620.00 m/s
  
35
Not Available
  
Optical Properties
  
  
Allotropes
No
  
Yes
  
α Allotropes
Not Available
  
α-polonium
  
β Allotropes
Not Available
  
β-polonium
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Tb
  
Po
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Not Available
  
Ionization Energies
  
  
1st Energy Level
603.40 kJ/mol
  
99+
812.10 kJ/mol
  
14
2nd Energy Level
1,174.80 kJ/mol
  
99+
Not Available
  
3rd Energy Level
2,417.00 kJ/mol
  
99+
Not Available
  
4th Energy Level
4,203.00 kJ/mol
  
31
Not Available
  
Electrochemical Equivalent
1.98 g/amp-hr
  
31
3.90 g/amp-hr
  
8
Electron Work Function
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Xe] 4f9 6s2
  
[Xe] 4f14 5d10 6s2 6p4
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Monoclinic (MON)
  
Crystal Lattice
HCP-Crystal-Structure-of-Terbium.jpg#100
  
MON-Crystal-Structure-of-Polonium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Weight
158.93 amu
  
99+
Atomic Volume
19.20 cm3/mol
  
22
22.23 cm3/mol
  
13
Adjacent Atomic Numbers
  
  
Valence Electron Potential
46.80 (-eV)
  
33
Not Available
  
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
8.23 g/cm3
  
99+
9.20 g/cm3
  
99+
Density When Liquid (at m.p.)
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Vapor Pressure at 2000 K
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
Ductile, Malleable
  
NA
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Nonmagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Electrical Conductivity
0.01 106/cm Ω
  
99+
0.02 106/cm Ω
  
99+
Electron Affinity
50.00 kJ/mol
  
21
183.30 kJ/mol
  
3
Specific Heat
0.18 J/(kg K)
  
33
0.12 J/(kg K)
  
40
Molar Heat Capacity
28.91 J/mol·K
  
9
26.40 J/mol·K
  
28
Thermal Conductivity
11.10 W/m·K
  
99+
20.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
10.30 µm/(m·K)
  
38
23.50 µm/(m·K)
  
16
Enthalpy
  
  
Enthalpy of Vaporization
330.90 kJ/mol
  
26
60.30 kJ/mol
  
99+
Enthalpy of Fusion
10.80 kJ/mol
  
34
13.00 kJ/mol
  
26
Enthalpy of Atomization
314.00 kJ/mol
  
33
134.00 kJ/mol
  
99+
Standard Molar Entropy
73.20 J/mol.K
  
10
Not Available