Polonium vs Rhodium
Periodic Table
Symbol
Po
Rh
Group Number
16
2
9
9
Period Number
6
5
Block
p block
d block
Element Family
Post-Transition
Transition Metal
CAS Number
7440086
99+
7440166
99+
Space Group Name
Pm-3m
Fm_ 3m
Space Group Number
221.00
3
225.00
2
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.
- Rhodium is the rarest element out of all non-radioactive metals on the earth .
- Rhodium is one of the most durable and hard metal, which also have high reflectance.
Sources
Mining, Ores of metals
Earth's crust, Found As a By-product, Found in Minerals, Mining
History
Who Discovered
Pierre Curie and Marie Curie
William Hyde Wollaston
Discovery
In 1898
In 1804
Abundance
Abundance In Universe
Not Available
6 * 10-8 %
26
Abundance In Sun
~-9999 %
~0.0000002 %
25
Abundance In Meteorites
Not Available
0.00 %
36
Abundance In Earth's Crust
Not Available
0.00 %
99+
Abundance In Oceans
0.00 %
99+
Not Available
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.
- Rhodium metal is mainly used in catalytic converters for cars as it reduces nitrogen oxides in exhaust gases.
- It is used as an industrial catalyst for nitric acid, acetic acid, hydrogenation reaction, etc.
Industrial Uses
Aerospace Industry, Ammunition Industry
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Medical Uses
NA
NA
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Highly Toxic
NA
Present in Human Body
No
No
In Blood
0.00 Blood/mg dm-3
37
Not Available
In Bone
0.00 p.p.m.
36
Not Available
Physical Properties
Melting Point
254.00 °C
99+
1,966.00 °C
12
Boiling Point
962.00 °C
99+
3,727.00 °C
17
Appearance
Physical State
Solid
Solid
Color
Silver
Silvery White
Luster
NA
Metallic
Hardness
Mohs Hardness
Not Available
6.00
6
Brinell Hardness
Not Available
980.00 MPa
9
Vickers Hardness
Not Available
1,100.00 MPa
9
Speed of Sound
Not Available
4,700.00 m/s
15
Optical Properties
Reflectivity
Not Available
84.00 %
4
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
Rh
Isotopes
Known Isotopes
29
10
16
23
Electronegativity
Pauling Electronegativity
2.00
7
2.28
3
Allred Rochow Electronegativity
1.76
2
1.45
16
Mulliken-Jaffe Electronegativity
2.48
1
Not Available
Allen Electronegativity
2.19
2
1.56
24
Electropositivity
Pauling Electropositivity
2.00
99+
1.72
99+
Ionization Energies
1st Energy Level
812.10 kJ/mol
14
719.70 kJ/mol
29
2nd Energy Level
Not Available
1,740.00 kJ/mol
26
3rd Energy Level
Not Available
2,997.00 kJ/mol
27
Electrochemical Equivalent
3.90 g/amp-hr
8
1.28 g/amp-hr
99+
Electron Work Function
Not Available
4.98 eV
6
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Ionization, Radioactive Isotopes
Atomic Properties
Atomic Number
84
32
45
99+
Electron Configuration
[Xe] 4f14 5d10 6s2 6p4
[Kr] 4d8 5s1
Crystal Structure
Monoclinic (MON)
Face Centered Cubic (FCC)
Crystal Lattice
MON-Crystal-Structure-of-Polonium.jpg#100
FCC-Crystal-Structure-of-Rhodium.jpg#100
Atom
Number of Protons
84
32
45
99+
Number of Neutrons
125
19
58
99+
Number of Electrons
84
32
45
99+
Radius of an Atom
Atomic Radius
168.00 pm
23
134.00 pm
99+
Covalent Radius
140.00 pm
99+
142.00 pm
99+
Van der Waals Radius
197.00 pm
29
200.00 pm
28
Atomic Weight
209.00 amu
28
102.91 amu
99+
Atomic Volume
22.23 cm3/mol
13
8.30 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
Not Available
64.00 (-eV)
22
Lattice Constant
335.90 pm
99+
380.34 pm
27
Lattice Angles
π/2, π/2, π/2
π/2, π/2, π/2
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
9.20 g/cm3
99+
12.41 g/cm3
28
Density When Liquid (at m.p.)
9.40 g/cm3
19
10.70 g/cm3
14
Tensile Strength
Not Available
951.00 MPa
5
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 2000 K
Not Available
0.02 (Pa)
19
Elasticity properties
Shear Modulus
Not Available
150.00 GPa
6
Bulk Modulus
Not Available
275.00 GPa
5
Young's Modulus
Not Available
380.00 GPa
5
Poisson Ratio
Not Available
0.26
22
Other Mechanical Properties
NA
Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
9.32
31
12.41
20
Magnetic Ordering
Nonmagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
0.40 nΩ·m
99+
43.30 nΩ·m
99+
Electrical Conductivity
0.02 106/cm Ω
99+
0.21 106/cm Ω
8
Electron Affinity
183.30 kJ/mol
3
109.70 kJ/mol
7
Thermal Properties
Specific Heat
0.12 J/(kg K)
40
0.24 J/(kg K)
22
Molar Heat Capacity
26.40 J/mol·K
28
24.98 J/mol·K
99+
Thermal Conductivity
20.00 W/m·K
99+
150.00 W/m·K
9
Critical Temperature
Not Available
Not Available
Thermal Expansion
23.50 µm/(m·K)
16
8.20 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
60.30 kJ/mol
99+
495.40 kJ/mol
12
Enthalpy of Fusion
13.00 kJ/mol
26
21.76 kJ/mol
10
Enthalpy of Atomization
134.00 kJ/mol
99+
556.50 kJ/mol
12
Standard Molar Entropy
Not Available
31.50 J/mol.K
99+
|
||
|
||
|
