Polonium Cerium Comparison
Periodic Table
Symbol
Po
Ce
Group Number
16
2
Not Available
Period Number
6
6
Block
p block
f block
Element Family
Post-Transition
Lanthanide
CAS Number
7440086
99+
7440451
99+
Space Group Name
Pm-3m
P63/mmc
Space Group Number
221.00
3
194.00
5
Facts
Interesting Facts
- 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.
- 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.
Sources
Mining, Ores of metals
Found in Minerals, Mining, Ores of Minerals
History
Who Discovered
Pierre Curie and Marie Curie
Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger
Discovery
In 1898
In 1803
Abundance
Abundance In Universe
Not Available
1 * 10-6 %
16
Abundance In Sun
~-9999 %
~0.0000004 %
23
Abundance In Meteorites
Not Available
0.00 %
27
Abundance In Earth's Crust
Not Available
0.01 %
18
Abundance In Oceans
0.00 %
99+
0.00 %
33
Uses
Uses & Benefits
- 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.
- 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.
Industrial Uses
Aerospace Industry, Ammunition Industry
Chemical Industry
Medical Uses
NA
Medical Research
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Highly Toxic
Moderately Toxic
Present in Human Body
No
Yes
In Blood
0.00 Blood/mg dm-3
37
0.00 Blood/mg dm-3
30
In Bone
0.00 p.p.m.
36
2.70 p.p.m.
14
Physical Properties
Melting Point
254.00 °C
99+
795.00 °C
99+
Boiling Point
962.00 °C
99+
3,257.00 °C
23
Appearance
Physical State
Solid
Solid
Color
Silver
Silvery White
Luster
NA
Lustrous
Hardness
Mohs Hardness
Not Available
2.50
14
Brinell Hardness
Not Available
186.00 MPa
99+
Vickers Hardness
Not Available
210.00 MPa
32
Speed of Sound
Not Available
2,100.00 m/s
99+
Optical Properties
Allotropes
Yes
No
α Allotropes
α-polonium
Not Available
β Allotropes
β-polonium
Not Available
γ Allotropes
Not Available
Not Available
Chemical Properties
Chemical Formula
Po
Ce
Isotopes
Known Isotopes
29
10
30
9
Electronegativity
Pauling Electronegativity
2.00
7
1.12
99+
Allred Rochow Electronegativity
1.76
2
1.08
31
Mulliken-Jaffe Electronegativity
2.48
1
Not Available
Allen Electronegativity
2.19
2
Not Available
Electropositivity
Pauling Electropositivity
2.00
99+
2.88
11
Ionization Energies
1st Energy Level
812.10 kJ/mol
14
534.40 kJ/mol
99+
2nd Energy Level
Not Available
1,050.00 kJ/mol
99+
3rd Energy Level
Not Available
1,949.00 kJ/mol
99+
4th Energy Level
Not Available
3,547.00 kJ/mol
99+
5th Energy Level
Not Available
6,325.00 kJ/mol
22
6th Energy Level
Not Available
7,490.00 kJ/mol
21
Electrochemical Equivalent
3.90 g/amp-hr
8
1.74 g/amp-hr
99+
Electron Work Function
Not Available
2.84 eV
39
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
84
32
58
99+
Electron Configuration
[Xe] 4f14 5d10 6s2 6p4
[Xe] 4f1 5d1 6s2
Crystal Structure
Monoclinic (MON)
Double Hexagonal Close Packed (DHCP)
Crystal Lattice
MON-Crystal-Structure-of-Polonium.jpg#100
DHCP-Crystal-Structure-of-Cerium.jpg#100
Atom
Number of Protons
84
32
58
99+
Number of Neutrons
125
19
82
99+
Number of Electrons
84
32
58
99+
Radius of an Atom
Atomic Radius
168.00 pm
23
181.80 pm
12
Covalent Radius
140.00 pm
99+
204.00 pm
8
Van der Waals Radius
197.00 pm
29
235.00 pm
17
Atomic Weight
209.00 amu
28
140.12 amu
99+
Atomic Volume
22.23 cm3/mol
13
20.67 cm3/mol
17
Adjacent Atomic Numbers
Valence Electron Potential
Not Available
41.78 (-eV)
99+
Lattice Constant
335.90 pm
99+
362.00 pm
34
Lattice Angles
π/2, π/2, π/2
π/2, π/2, 2 π/3
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
9.20 g/cm3
99+
6.77 g/cm3
99+
Density When Liquid (at m.p.)
9.40 g/cm3
19
6.55 g/cm3
38
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
0.00 (Pa)
34
Vapor Pressure at 2000 K
Not Available
1.04 (Pa)
13
Elasticity properties
Shear Modulus
Not Available
13.50 GPa
99+
Bulk Modulus
Not Available
21.50 GPa
99+
Young's Modulus
Not Available
33.60 GPa
99+
Poisson Ratio
Not Available
0.24
27
Other Mechanical Properties
NA
Ductile, Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
9.32
31
6.77
99+
Magnetic Ordering
Nonmagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
0.40 nΩ·m
99+
828.00 nΩ·m
3
Electrical Conductivity
0.02 106/cm Ω
99+
0.01 106/cm Ω
99+
Electron Affinity
183.30 kJ/mol
3
50.00 kJ/mol
21
Thermal Properties
Specific Heat
0.12 J/(kg K)
40
0.19 J/(kg K)
32
Molar Heat Capacity
26.40 J/mol·K
28
26.94 J/mol·K
23
Thermal Conductivity
20.00 W/m·K
99+
11.30 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
23.50 µm/(m·K)
16
6.30 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
60.30 kJ/mol
99+
414.00 kJ/mol
16
Enthalpy of Fusion
13.00 kJ/mol
26
5.46 kJ/mol
99+
Enthalpy of Atomization
134.00 kJ/mol
99+
381.00 kJ/mol
23
Standard Molar Entropy
Not Available
72.00 J/mol.K
12
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