Polonium vs Thallium
Periodic Table
Symbol
Po
Tl
Group Number
16
2
13
5
Period Number
6
6
Block
p block
p block
Element Family
Post-Transition
Post-Transition
CAS Number
7440086
99+
7440280
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.
- Compounds of Thallium metal are highly Toxic.
- Thallium metal is being suspected as a human carcinogen.
Sources
Mining, Ores of metals
Found As a By-product, Ores of metals, Ores of Minerals
History
Who Discovered
Pierre Curie and Marie Curie
William Crookes
Discovery
In 1898
In 1861
Abundance
Abundance In Universe
Not Available
5 * 10-9 %
32
Abundance In Sun
~-9999 %
~0.0000001 %
26
Abundance In Meteorites
Not Available
0.00 %
99+
Abundance In Earth's Crust
Not Available
0.00 %
99+
Abundance In Oceans
0.00 %
99+
0.00 %
34
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.
- Thallium is a toxic metal and hence it has limited uses. Thallium metal is mostly used for producing photoelectric cells.
- In thermometer’s mercury alloy has 8% of thallium, as it has a melting point lower than 20°C.
Industrial Uses
Aerospace Industry, Ammunition Industry
Chemical Industry
Medical Uses
NA
Medical Research
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Highly Toxic
Highly Toxic
Present in Human Body
No
Yes
In Blood
0.00 Blood/mg dm-3
37
0.00 Blood/mg dm-3
34
In Bone
0.00 p.p.m.
36
0.00 p.p.m.
33
Physical Properties
Melting Point
254.00 °C
99+
303.50 °C
99+
Boiling Point
962.00 °C
99+
1,457.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Silver
Silvery White
Luster
NA
NA
Hardness
Mohs Hardness
Not Available
1.20
20
Brinell Hardness
Not Available
26.50 MPa
99+
Speed of Sound
Not Available
818.00 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
Tl
Isotopes
Known Isotopes
29
10
32
7
Electronegativity
Pauling Electronegativity
2.00
7
1.62
21
Sanderson Electronegativity
Not Available
2.25
5
Allred Rochow Electronegativity
1.76
2
1.44
17
Mulliken-Jaffe Electronegativity
2.48
1
1.96
6
Allen Electronegativity
2.19
2
1.79
13
Electropositivity
Pauling Electropositivity
2.00
99+
2.38
33
Ionization Energies
1st Energy Level
812.10 kJ/mol
14
589.40 kJ/mol
99+
2nd Energy Level
Not Available
1,971.00 kJ/mol
14
3rd Energy Level
Not Available
2,878.00 kJ/mol
32
Electrochemical Equivalent
3.90 g/amp-hr
8
7.63 g/amp-hr
2
Electron Work Function
Not Available
3.84 eV
28
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
84
32
81
35
Electron Configuration
[Xe] 4f14 5d10 6s2 6p4
[Xe] 4f14 5d10 6s2 6p1
Crystal Structure
Monoclinic (MON)
Hexagonal Close Packed (HCP)
Crystal Lattice
MON-Crystal-Structure-of-Polonium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
84
32
81
35
Number of Neutrons
125
19
123
20
Number of Electrons
84
32
81
35
Radius of an Atom
Atomic Radius
168.00 pm
23
170.00 pm
22
Covalent Radius
140.00 pm
99+
145.00 pm
39
Van der Waals Radius
197.00 pm
29
196.00 pm
30
Atomic Weight
209.00 amu
28
204.38 amu
31
Atomic Volume
22.23 cm3/mol
13
17.20 cm3/mol
31
Adjacent Atomic Numbers
Valence Electron Potential
Not Available
9.60 (-eV)
99+
Lattice Constant
335.90 pm
99+
345.66 pm
99+
Lattice Angles
π/2, π/2, π/2
π/2, π/2, 2 π/3
Lattice C/A Ratio
Not Available
1.60
6
Mechanical Properties
Density
Density At Room Temperature
9.20 g/cm3
99+
11.85 g/cm3
31
Density When Liquid (at m.p.)
9.40 g/cm3
19
11.22 g/cm3
13
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
16.90 (Pa)
5
Elasticity properties
Shear Modulus
Not Available
2.80 GPa
99+
Bulk Modulus
Not Available
43.00 GPa
28
Young's Modulus
Not Available
8.00 GPa
99+
Poisson Ratio
Not Available
0.45
2
Other Mechanical Properties
NA
Ductile, Sectile
Magnetic Properties
Magnetic Characteristics
Specific Gravity
9.32
31
11.85
22
Magnetic Ordering
Nonmagnetic
Diamagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
0.40 nΩ·m
99+
0.18 nΩ·m
99+
Electrical Conductivity
0.02 106/cm Ω
99+
0.06 106/cm Ω
32
Electron Affinity
183.30 kJ/mol
3
19.20 kJ/mol
32
Thermal Properties
Specific Heat
0.12 J/(kg K)
40
0.13 J/(kg K)
39
Molar Heat Capacity
26.40 J/mol·K
28
26.32 J/mol·K
29
Thermal Conductivity
20.00 W/m·K
99+
46.10 W/m·K
33
Critical Temperature
Not Available
Not Available
Thermal Expansion
23.50 µm/(m·K)
16
29.90 µm/(m·K)
12
Enthalpy
Enthalpy of Vaporization
60.30 kJ/mol
99+
162.10 kJ/mol
99+
Enthalpy of Fusion
13.00 kJ/mol
26
4.27 kJ/mol
99+
Enthalpy of Atomization
134.00 kJ/mol
99+
179.90 kJ/mol
99+
Standard Molar Entropy
Not Available
64.20 J/mol.K
19
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