Cerium vs Promethium
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
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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