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Cerium vs Promethium


Promethium vs Cerium


Periodic Table

Symbol
Ce   
Pm   

Group Number
Not Available   
Not Available   

Period Number
6   
6   

Block
f block   
f block   

Element Family
Lanthanide   
Lanthanide   

CAS Number
7440451   
99+
7440122   
99+

Space Group Name
P63/mmc   
Not Available   

Space Group Number
194.00   
5
Not Available   

Facts

Interesting Facts
  • Cerium is a rare earth metal but still it is not rare at all.
  • It’s non-toxic compound Cerium sulfide has a rich red color and it is used as a pigment.
  • Cerium metal is also used in Flat screen TVs, light bulb, floodlights, etc.
  
  • Promethium metal found in Pitchblende.
  • Promethium metal is highly radioactive metal.
  

Sources
Found in Minerals, Mining, Ores of Minerals   
Found in Minerals, Mining   

History
  
  

Who Discovered
Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger   
Chien Shiung Wu, Emilio Segrè, Hans Bethe   

Discovery
In 1803   
In 1942   

Abundance
  
  

Abundance In Universe
1 * 10-6 %   
16
Not Available   

Abundance In Sun
~0.0000004 %   
23
~-9999 %   

Abundance In Meteorites
0.00 %   
27
Not Available   

Abundance In Earth's Crust
0.01 %   
18
Not Available   

Abundance In Oceans
0.00 %   
33
Not Available   

Uses

Uses & Benefits
  • It is used to include flints for cigarette lighters.
  • Its compound Cerium (Ill) Oxide is used as a catalyst; it is put inside the walls of the oven as it prevents from the buildup of cooking residues.
  
  • 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
Chemical Industry   
NA   

Medical Uses
Medical Research   
NA   

Other Uses
Alloys   
NA   

Biological Properties
  
  

Toxicity
Moderately Toxic   
Non Toxic   

Present in Human Body
Yes   
No   

In Blood
0.00 Blood/mg dm-3   
30
0.00 Blood/mg dm-3   
37

In Bone
2.70 p.p.m.   
14
Not Available   

Physical Properties

Melting Point
795.00 °C   
99+
1,042.00 °C   
99+

Boiling Point
3,257.00 °C   
23
3,000.00 °C   
31

Appearance
  
  

Physical State
Solid   
Solid   

Color
Silvery White   
Unknown   

Luster
Lustrous   
Metallic   

Hardness
  
  

Mohs Hardness
2.50   
14
Not Available   

Brinell Hardness
186.00 MPa   
99+
Not Available   

Vickers Hardness
210.00 MPa   
32
Not Available   

Speed of Sound
2,100.00 m/s   
99+
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
Ce   
Pm   

Isotopes
  
  

Known Isotopes
30   
9
27   
12

Electronegativity
  
  

Pauling Electronegativity
1.12   
99+
Not Available   

Allred Rochow Electronegativity
1.08   
31
1.07   
32

Electropositivity
  
  

Pauling Electropositivity
2.88   
11
Not Available   

Ionization Energies
  
  

1st Energy Level
534.40 kJ/mol   
99+
540.00 kJ/mol   
99+

2nd Energy Level
1,050.00 kJ/mol   
99+
1,050.00 kJ/mol   
99+

3rd Energy Level
1,949.00 kJ/mol   
99+
2,150.00 kJ/mol   
99+

4th Energy Level
3,547.00 kJ/mol   
99+
3,970.00 kJ/mol   
38

5th Energy Level
6,325.00 kJ/mol   
22
Not Available   

6th Energy Level
7,490.00 kJ/mol   
21
Not Available   

Electrochemical Equivalent
1.74 g/amp-hr   
99+
1.80 g/amp-hr   
36

Electron Work Function
2.84 eV   
39
Not Available   

Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility   
Ionization, Radioactive Isotopes, Solubility   

Atomic Properties

Atomic Number
58   
99+
61   
99+

Electron Configuration
[Xe] 4f1 5d1 6s2   
[Xe] 4f5 6s2   

Crystal Structure
Double Hexagonal Close Packed (DHCP)   
Double Hexagonal Close Packed (DHCP)   

Crystal Lattice
DHCP-Crystal-Structure-of-Cerium.jpg#100   
DHCP-Crystal-Structure-of-Promethium.jpg#100   

Atom
  
  

Number of Protons
58   
99+
61   
99+

Number of Neutrons
82   
99+
84   
40

Number of Electrons
58   
99+
61   
99+

Radius of an Atom
  
  

Atomic Radius
181.80 pm   
12
183.00 pm   
10

Covalent Radius
204.00 pm   
8
199.00 pm   
12

Van der Waals Radius
235.00 pm   
17
236.00 pm   
16

Atomic Weight
140.12 amu   
99+
145.00 amu   
99+

Atomic Volume
20.67 cm3/mol   
17
22.39 cm3/mol   
12

Adjacent Atomic Numbers
  
  

Previous Element
Lanthanum
  
Neodymium
  

Next Element
Samarium
  

Valence Electron Potential
41.78 (-eV)   
99+
44.10 (-eV)   
39

Lattice Constant
362.00 pm   
34
Not Available   

Lattice Angles
π/2, π/2, 2 π/3   
Unknown   

Lattice C/A Ratio
Not Available   
Not Available   

Mechanical Properties

Density
  
  

Density At Room Temperature
6.77 g/cm3   
99+
7.26 g/cm3   
99+

Density When Liquid (at m.p.)
6.55 g/cm3   
38
Not Available   

Tensile Strength
Not Available   
Not Available   

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Vapor Pressure at 1000 K
0.00 (Pa)   
34
Not Available   

Vapor Pressure at 2000 K
1.04 (Pa)   
13
Not Available   

Elasticity properties
  
  

Shear Modulus
13.50 GPa   
99+
18.00 GPa   
36

Bulk Modulus
21.50 GPa   
99+
33.00 GPa   
36

Young's Modulus
33.60 GPa   
99+
46.00 GPa   
38

Poisson Ratio
0.24   
27
0.28   
17

Other Mechanical Properties
Ductile, Malleable   
NA   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
6.77   
99+
7.26   
99+

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Conductor   
Conductor   

Resistivity
828.00 nΩ·m   
3
0.75 nΩ·m   
99+

Electrical Conductivity
0.01 106/cm Ω   
99+
Not Available   

Electron Affinity
50.00 kJ/mol   
21
50.00 kJ/mol   
21

Thermal Properties

Specific Heat
0.19 J/(kg K)   
32
0.18 J/(kg K)   
33

Molar Heat Capacity
26.94 J/mol·K   
23
Not Available   

Thermal Conductivity
11.30 W/m·K   
99+
17.90 W/m·K   
99+

Critical Temperature
Not Available   
Not Available   

Thermal Expansion
6.30 µm/(m·K)   
99+
9.00 µm/(m·K)   
99+

Enthalpy
  
  

Enthalpy of Vaporization
414.00 kJ/mol   
16
Not Available   

Enthalpy of Fusion
5.46 kJ/mol   
99+
7.50 kJ/mol   
99+

Enthalpy of Atomization
381.00 kJ/mol   
23
310.00 kJ/mol   
34

Standard Molar Entropy
72.00 J/mol.K   
12
Not Available   

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