Symbol
Po
Ce
Group Number
163
0
17
👆🏻
Period Number
66
2
7
👆🏻
Block
p block
f block
Element Family
Post-Transition
Lanthanide
CAS Number
74400867440451
7429905
54386242
👆🏻
Space Group Name
Pm-3m
P63/mmc
Space Group Number
221.00194.00
11
276
👆🏻
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
0.00 %0.00 %
0
0.11
👆🏻
Abundance In Sun
-0.00 %
0
0.1
👆🏻
Abundance In Meteorites
-0.00 %
0
22
👆🏻
Abundance In Earth's Crust
0.00 %0.01 %
1E-37
8.1
👆🏻
Abundance In Oceans
0.00 %0.00 %
0
1.1
👆🏻
Abundance In Humans
0.00 %0.00 %
0
1.4
👆🏻
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
-
Medical Research
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Highly Toxic
Moderately Toxic
Present in Human Body
✔
✘
✔
✘
In Blood
0.00 Blood/mg dm-30.00 Blood/mg dm-3
0
1970
👆🏻
In Bone
0.00 p.p.m.2.70 p.p.m.
0
170000
👆🏻
Melting Point
254.00 °C795.00 °C
-38.83
3410
👆🏻
Boiling Point
962.00 °C3,257.00 °C
0
5660
👆🏻
Appearance
Physical State
Solid
Solid
Color
Silver
Silvery White
Luster
-
Lustrous
Hardness
Mohs Hardness
2.502.50
0.2
8.5
👆🏻
Brinell Hardness
70.00 MPa186.00 MPa
0.14
3490
👆🏻
Vickers Hardness
30.00 MPa210.00 MPa
0
3920
👆🏻
Speed of Sound
2,260.00 m/s2,100.00 m/s
818
16200
👆🏻
Optical Properties
Refractive Index
2.702.20
0.155
3.41
👆🏻
Reflectivity
50.00 %68.00 %
5
97
👆🏻
Allotropes
✔
✘
✔
✘
α Allotropes
α-polonium
-
β Allotropes
β-polonium
-
γ Allotropes
-
-
Chemical Formula
Po
Ce
Isotopes
Known Isotopes
2930
0
38
👆🏻
Electronegativity
Pauling Electronegativity
2.001.12
0
2.6
👆🏻
Sanderson Electronegativity
2.001.12
0.22
2.56
👆🏻
Allred Rochow Electronegativity
1.761.08
0.86
1.9
👆🏻
Mulliken-Jaffe Electronegativity
2.481.12
0.62
2.48
👆🏻
Allen Electronegativity
2.191.12
0.659
2.7
👆🏻
Electropositivity
Pauling Electropositivity
2.002.88
1.46
3.3
👆🏻
Ionization Energies
1st Energy Level
812.10 kJ/mol534.40 kJ/mol
375.7
26130
👆🏻
2nd Energy Level
1,833.20 kJ/mol1,050.00 kJ/mol
392.8
28750
👆🏻
3rd Energy Level
812.10 kJ/mol1,949.00 kJ/mol
392.8
34230
👆🏻
4th Energy Level
8,121.00 kJ/mol3,547.00 kJ/mol
375.7
37066
👆🏻
5th Energy Level
8,120.00 kJ/mol6,325.00 kJ/mol
392
97510
👆🏻
6th Energy Level
8,120.00 kJ/mol7,490.00 kJ/mol
1007
105800
👆🏻
7th Energy level
8,120.00 kJ/mol5,340.00 kJ/mol
1007
114300
👆🏻
8th Energy Level
8,120.00 kJ/mol5,340.00 kJ/mol
730
125300
👆🏻
9th Energy Level
8,120.00 kJ/mol5,340.00 kJ/mol
1007
134700
👆🏻
10th Energy Level
8,120.00 kJ/mol5,340.00 kJ/mol
392
144300
👆🏻
11th Energy Level
8,120.00 kJ/mol5,340.00 kJ/mol
392
169988
👆🏻
12th Energy Level
8,120.00 kJ/mol5,340.00 kJ/mol
0
189368
👆🏻
13th Energy Level
8,120.00 kJ/mol5,650.00 kJ/mol
1007
76015
👆🏻
14th Energy Level
8,120.00 kJ/mol5,340.00 kJ/mol
380
86450
👆🏻
15th Energy Level
81,200.00 kJ/mol53,400.00 kJ/mol
33000
100700
👆🏻
16th Energy Level
81,200.00 kJ/mol53,400.00 kJ/mol
375.7
109480
👆🏻
17th Energy Level
812.10 kJ/mol534.40 kJ/mol
375.7
122200
👆🏻
18th Energy Level
8,120.00 kJ/mol5,340.00 kJ/mol
0
134810
👆🏻
19th Energy Level
812.10 kJ/mol534.40 kJ/mol
375.7
148700
👆🏻
20th Energy Level
812.00 kJ/mol534.00 kJ/mol
0
171200
👆🏻
21st Energy Level
812.10 kJ/mol5,346.00 kJ/mol
375.7
179100
👆🏻
22nd Energy Level
812.00 kJ/mol594.00 kJ/mol
330
184900
👆🏻
23rd Energy Level
812.10 kJ/mol5,346.00 kJ/mol
357.6
198800
👆🏻
24th Energy Level
812.10 kJ/mol565.50 kJ/mol
297.3
195200
👆🏻
25th Energy Level
812.10 kJ/mol534.40 kJ/mol
0
121900
👆🏻
26th Energy Level
812.10 kJ/mol565.50 kJ/mol
357.6
127700
👆🏻
27th Energy Level
812.10 kJ/mol565.50 kJ/mol
0
133800
👆🏻
28th Energy Level
812.10 kJ/mol565.50 kJ/mol
297.3
139800
👆🏻
29th Energy Level
812.10 kJ/mol565.50 kJ/mol
0
148100
👆🏻
30th Energy Level
812.00 kJ/mol594.00 kJ/mol
0
154500
👆🏻
Electrochemical Equivalent
3.90 g/amp-hr1.74 g/amp-hr
0.16812
8.3209
👆🏻
Electron Work Function
4.50 eV2.84 eV
2.14
6
👆🏻
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Number
8458
3
117
👆🏻
Electron Configuration
[Xe] 4f14 5d10 6s2 6p4
[Xe] 4f1 5d1 6s2
Crystal Structure
Monoclinic (MON)
Double Hexagonal Close Packed (DHCP)
Crystal Lattice
Atom
Number of Protons
8458
3
117
👆🏻
Number of Neutrons
12582
4
285
👆🏻
Number of Electrons
8458
3
117
👆🏻
Radius of an Atom
Atomic Radius
168.00 pm181.80 pm
0
348
👆🏻
Covalent Radius
140.00 pm204.00 pm
0
260
👆🏻
Van der Waals Radius
197.00 pm235.00 pm
0
348
👆🏻
Atomic Weight
209.00 amu140.12 amu
6.94
294
👆🏻
Atomic Volume
22.23 cm3/mol20.67 cm3/mol
1.39
71.07
👆🏻
Adjacent Atomic Numbers
Previous Element
Next Element
Valence Electron Potential
9.30 (-eV)41.78 (-eV)
0
392.42
👆🏻
Lattice Constant
335.90 pm362.00 pm
0
891.25
👆🏻
Lattice Angles
π/2, π/2, π/2
π/2, π/2, 2 π/3
Lattice C/A Ratio
1.461.59
0.423
1.9
👆🏻
Density
Density At Room Temperature
9.20 g/cm36.77 g/cm3
0.534
40.7
👆🏻
Density When Liquid (at m.p.)
9.40 g/cm36.55 g/cm3
0.512
41
👆🏻
Tensile Strength
50.00 MPa270.00 MPa
0.1
11000
👆🏻
Viscosity
0.000.00
1.5E-05
0.0035
👆🏻
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)0.00 (Pa)
0
121
👆🏻
Vapor Pressure at 2000 K
0.00 (Pa)1.04 (Pa)
0
774
👆🏻
Elasticity properties
Shear Modulus
24.00 GPa13.50 GPa
1.3
222
👆🏻
Bulk Modulus
46.00 GPa21.50 GPa
0
462
👆🏻
Young's Modulus
46.00 GPa33.60 GPa
0
528
👆🏻
Poisson Ratio
0.230.24
0.032
0.47
👆🏻
Other Mechanical Properties
-
Ductile, Malleable
Magnetic Characteristics
Specific Gravity
9.326.77
0.53
4500
👆🏻
Magnetic Ordering
Nonmagnetic
Paramagnetic
Permeability
0.00 H/m0.00 H/m
1.25643E-06
0.0063
👆🏻
Susceptibility
0.000.00
-0.000166
200000
👆🏻
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
0.40 nΩ·m828.00 nΩ·m
0.1
961
👆🏻
Electrical Conductivity
0.02 106/cm Ω0.01 106/cm Ω
0
0.63
👆🏻
Electron Affinity
183.30 kJ/mol50.00 kJ/mol
0
222.8
👆🏻
Specific Heat
0.12 J/(kg K)0.19 J/(kg K)
0.1
3.6
👆🏻
Molar Heat Capacity
26.40 J/mol·K26.94 J/mol·K
13.1
62.7
👆🏻
Thermal Conductivity
20.00 W/m·K11.30 W/m·K
0
429
👆🏻
Critical Temperature
527.00 K1,071.00 K
26.3
3695
👆🏻
Thermal Expansion
23.50 µm/(m·K)6.30 µm/(m·K)
4.5
97
👆🏻
Enthalpy
Enthalpy of Vaporization
60.30 kJ/mol414.00 kJ/mol
7.32
799.1
👆🏻
Enthalpy of Fusion
13.00 kJ/mol5.46 kJ/mol
2.1
35.23
👆🏻
Enthalpy of Atomization
134.00 kJ/mol381.00 kJ/mol
61.5
837
👆🏻
Standard Molar Entropy
41.10 J/mol.K72.00 J/mol.K
9.5
198.1
👆🏻