Francium vs Promethium
Periodic Table
Symbol
Fr
Pm
Group Number
1
17
Not Available
Period Number
7
6
Block
s block
f block
Element Family
Alkali
Lanthanide
CAS Number
7440735
18
7440122
99+
Space Group Name
Not Available
Not Available
Space Group Number
Not Available
Not Available
Facts
Interesting Facts
- 223 Francium has the longest half life at 21.8.
- Francium metal is produced by alpha decay in 227Actinium 227.
- Promethium metal found in Pitchblende.
- Promethium metal is highly radioactive metal.
Sources
Formed by Decay Process, Mining
Found in Minerals, Mining
History
Who Discovered
Marguerite Perey
Chien Shiung Wu, Emilio Segrè, Hans Bethe
Discovery
In 1939
In 1942
Abundance
Uses
Uses & Benefits
- Francium has no known uses as it has a half life of only 22 minutes.
- 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.
Industrial Uses
NA
NA
Medical Uses
NA
NA
Other Uses
NA
NA
Biological Properties
Toxicity
NA
Non Toxic
Present in Human Body
No
No
In Blood
0.00 Blood/mg dm-3
37
0.00 Blood/mg dm-3
37
In Bone
0.00 p.p.m.
36
Not Available
Physical Properties
Melting Point
27.00 °C
99+
1,042.00 °C
99+
Boiling Point
677.00 °C
99+
3,000.00 °C
31
Appearance
Physical State
Solid
Solid
Color
NA
Unknown
Luster
NA
Metallic
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
Fr
Pm
Isotopes
Known Isotopes
33
6
27
12
Electronegativity
Pauling Electronegativity
0.70
99+
Not Available
Allred Rochow Electronegativity
0.86
99+
1.07
32
Mulliken-Jaffe Electronegativity
0.68
25
Not Available
Allen Electronegativity
0.67
99+
Not Available
Electropositivity
Pauling Electropositivity
3.30
1
Not Available
Ionization Energies
1st Energy Level
380.00 kJ/mol
99+
540.00 kJ/mol
99+
2nd Energy Level
Not Available
1,050.00 kJ/mol
99+
3rd Energy Level
Not Available
2,150.00 kJ/mol
99+
4th Energy Level
Not Available
3,970.00 kJ/mol
38
Electrochemical Equivalent
8.32 g/amp-hr
1
1.80 g/amp-hr
36
Electron Work Function
Not Available
Not Available
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
87
31
61
99+
Electron Configuration
[Rn] 7s1
[Xe] 4f5 6s2
Crystal Structure
Body Centered Cubic (BCC)
Double Hexagonal Close Packed (DHCP)
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
DHCP-Crystal-Structure-of-Promethium.jpg#100
Atom
Number of Protons
87
31
61
99+
Number of Neutrons
136
17
84
40
Number of Electrons
87
31
61
99+
Radius of an Atom
Atomic Radius
Not Available
183.00 pm
10
Covalent Radius
260.00 pm
1
199.00 pm
12
Van der Waals Radius
348.00 pm
1
236.00 pm
16
Atomic Weight
223.00 amu
27
145.00 amu
99+
Atomic Volume
Not Available
22.39 cm3/mol
12
Adjacent Atomic Numbers
Valence Electron Potential
8.00 (-eV)
99+
44.10 (-eV)
39
Lattice Constant
Not Available
Not Available
Lattice Angles
NA
Unknown
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
1.87 g/cm3
99+
7.26 g/cm3
99+
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Elasticity properties
Shear Modulus
Not Available
18.00 GPa
36
Bulk Modulus
Not Available
33.00 GPa
36
Young's Modulus
Not Available
46.00 GPa
38
Poisson Ratio
Not Available
0.28
17
Other Mechanical Properties
NA
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
Not Available
7.26
99+
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Poor Conductor
Conductor
Resistivity
3.00 nΩ·m
99+
0.75 nΩ·m
99+
Electrical Conductivity
0.03 106/cm Ω
40
Not Available
Electron Affinity
Not Available
50.00 kJ/mol
21
Thermal Properties
Specific Heat
Not Available
0.18 J/(kg K)
33
Molar Heat Capacity
Not Available
Not Available
Thermal Conductivity
15.00 W/m·K
99+
17.90 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
Not Available
9.00 µm/(m·K)
99+
Enthalpy
Enthalpy of Fusion
Not Available
7.50 kJ/mol
99+
Enthalpy of Atomization
71.00 kJ/mol
99+
310.00 kJ/mol
34
Standard Molar Entropy
Not Available
Not Available
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