Promethium Fermium Comparison
Periodic Table
Symbol
Pm
Fm
Group Number
Not Available
Not Available
Period Number
6
7
Block
f block
f block
Element Family
Lanthanide
Actinide
CAS Number
7440122
99+
7440724
19
Space Group Name
Not Available
Not Available
Space Group Number
Not Available
Not Available
Facts
Interesting Facts
- Promethium metal found in Pitchblende.
- Promethium metal is highly radioactive metal.
- Fermium metal is highly radioactive in nature.
- Fermium is synthetically produced metal.
Sources
Found in Minerals, Mining
Bombarding Pu-239 with Neutrons
History
Who Discovered
Chien Shiung Wu, Emilio Segrè, Hans Bethe
Lawrence Berkeley National Laboratory
Discovery
In 1942
In 1952
Abundance
Uses
Uses & Benefits
- It is used for research purpose. Very small amount of this metal is used in atomic batteries.
- Its radioactive decay is used for a phosphor to give off light. The light emitted is converted into electricity.
- Currently known uses of Fermium metal are limited to research purpose only.
Industrial Uses
NA
NA
Medical Uses
NA
NA
Other Uses
NA
NA
Biological Properties
Toxicity
Non Toxic
Unknown
Present in Human Body
No
No
In Blood
0.00 Blood/mg dm-3
37
0.00 Blood/mg dm-3
37
In Bone
Not Available
0.00 p.p.m.
36
Physical Properties
Melting Point
1,042.00 °C
99+
1,527.00 °C
26
Boiling Point
3,000.00 °C
31
Not Available
Appearance
Physical State
Solid
Solid
Luster
Metallic
Not Defined
Hardness
Speed of Sound
Not Available
Not Available
Optical Properties
Allotropes
No
No
α Allotropes
Not Available
Not Available
β Allotropes
Not Available
Not Available
γ Allotropes
Not Available
Not Available
Chemical Properties
Chemical Formula
Pm
Fm
Isotopes
Known Isotopes
27
12
18
21
Electronegativity
Pauling Electronegativity
Not Available
1.30
32
Allred Rochow Electronegativity
1.07
32
1.20
27
Electropositivity
Pauling Electropositivity
Not Available
2.70
22
Ionization Energies
1st Energy Level
540.00 kJ/mol
99+
627.00 kJ/mol
99+
2nd Energy Level
1,050.00 kJ/mol
99+
1,225.00 kJ/mol
99+
3rd Energy Level
2,150.00 kJ/mol
99+
2,363.00 kJ/mol
99+
4th Energy Level
3,970.00 kJ/mol
38
3,792.00 kJ/mol
99+
Electrochemical Equivalent
1.80 g/amp-hr
36
3.20 g/amp-hr
13
Electron Work Function
Not Available
Not Available
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
Ionization, Radioactive Isotopes, Radioactivity
Atomic Properties
Atomic Number
61
99+
100
18
Electron Configuration
[Xe] 4f5 6s2
[Rn] 5f12 7s2
Crystal Structure
Double Hexagonal Close Packed (DHCP)
Not Known
Crystal Lattice
DHCP-Crystal-Structure-of-Promethium.jpg#100
Unknown-Crystal-Structure-of-Fermium.jpg#100
Atom
Number of Protons
61
99+
100
18
Number of Neutrons
84
40
157
7
Number of Electrons
61
99+
100
18
Radius of an Atom
Atomic Radius
183.00 pm
10
Not Available
Covalent Radius
199.00 pm
12
Not Available
Van der Waals Radius
236.00 pm
16
245.00 pm
9
Atomic Weight
145.00 amu
99+
257.00 amu
15
Atomic Volume
22.39 cm3/mol
12
Not Available
Adjacent Atomic Numbers
Valence Electron Potential
44.10 (-eV)
39
Not Available
Lattice Constant
Not Available
Not Available
Lattice Angles
Unknown
NA
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
7.26 g/cm3
99+
Not Available
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Elasticity properties
Shear Modulus
18.00 GPa
36
Not Available
Bulk Modulus
33.00 GPa
36
Not Available
Young's Modulus
46.00 GPa
38
Not Available
Poisson Ratio
0.28
17
Not Available
Other Mechanical Properties
NA
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
7.26
99+
Not Available
Magnetic Ordering
Paramagnetic
Unknown
Electrical Properties
Electrical Property
Conductor
Unknown
Resistivity
0.75 nΩ·m
99+
Not Available
Electron Affinity
50.00 kJ/mol
21
Not Available
Thermal Properties
Specific Heat
0.18 J/(kg K)
33
Not Available
Molar Heat Capacity
Not Available
Not Available
Thermal Conductivity
17.90 W/m·K
99+
Not Available
Critical Temperature
Not Available
Not Available
Thermal Expansion
9.00 µm/(m·K)
99+
Not Available
Enthalpy
Enthalpy of Fusion
7.50 kJ/mol
99+
Not Available
Enthalpy of Atomization
310.00 kJ/mol
34
Not Available
Standard Molar Entropy
Not Available
Not Available
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