Rhodium vs Protactinium
Periodic Table
Symbol
Rh
Pa
Group Number
9
9
Not Available
Period Number
5
7
Block
d block
f block
Element Family
Transition Metal
Actinide
CAS Number
7440166
99+
7440133
99+
Space Group Name
Fm_ 3m
I4/mmm
Space Group Number
225.00
2
139.00
8
Facts
Interesting Facts
- 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.
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
Sources
Earth's crust, Found As a By-product, Found in Minerals, Mining
Found in Uranium Ores, Mining, Ores of metals
History
Who Discovered
William Hyde Wollaston
William Crookes
Discovery
In 1804
In 1900
Abundance
Abundance In Universe
6 * 10-8 %
26
Not Available
Abundance In Sun
~0.0000002 %
25
~-9999 %
Abundance In Meteorites
0.00 %
36
Not Available
Abundance In Earth's Crust
0.00 %
99+
0.00 %
99+
Abundance In Oceans
Not Available
0.00 %
99+
Uses
Uses & Benefits
- 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.
- Currently known uses of Protactinium metal are limited to research purpose only.
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
NA
Medical Uses
NA
NA
Other Uses
Alloys
NA
Biological Properties
Toxicity
NA
Highly Toxic
Present in Human Body
No
No
In Blood
Not Available
0.00 Blood/mg dm-3
37
In Bone
Not Available
0.00 p.p.m.
36
Physical Properties
Melting Point
1,966.00 °C
12
1,568.00 °C
21
Boiling Point
3,727.00 °C
17
4,027.00 °C
12
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silver
Luster
Metallic
Metallic
Hardness
Mohs Hardness
6.00
6
Not Available
Brinell Hardness
980.00 MPa
9
Not Available
Vickers Hardness
1,100.00 MPa
9
Not Available
Speed of Sound
4,700.00 m/s
15
Not Available
Optical Properties
Reflectivity
84.00 %
4
Not Available
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
Rh
Pa
Isotopes
Known Isotopes
16
23
27
12
Electronegativity
Pauling Electronegativity
2.28
3
1.50
27
Allred Rochow Electronegativity
1.45
16
1.14
28
Allen Electronegativity
1.56
24
Not Available
Electropositivity
Pauling Electropositivity
1.72
99+
2.50
27
Ionization Energies
1st Energy Level
719.70 kJ/mol
29
568.00 kJ/mol
99+
2nd Energy Level
1,740.00 kJ/mol
26
1,128.00 kJ/mol
99+
3rd Energy Level
2,997.00 kJ/mol
27
1,814.00 kJ/mol
99+
4th Energy Level
Not Available
2,991.00 kJ/mol
99+
Electrochemical Equivalent
1.28 g/amp-hr
99+
1.72 g/amp-hr
99+
Electron Work Function
4.98 eV
6
Not Available
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
Ionization, Radioactive Isotopes, Radioactivity
Atomic Properties
Atomic Number
45
99+
91
27
Electron Configuration
[Kr] 4d8 5s1
[Rn] 5f2 6d1 7s2
Crystal Structure
Face Centered Cubic (FCC)
Tetragonal (TETR)
Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100
TETR-Crystal-Structure-of-Protactinium.jpg#100
Atom
Number of Protons
45
99+
91
27
Number of Neutrons
58
99+
122
21
Number of Electrons
45
99+
91
27
Radius of an Atom
Atomic Radius
134.00 pm
99+
163.00 pm
25
Covalent Radius
142.00 pm
99+
200.00 pm
11
Van der Waals Radius
200.00 pm
28
243.00 pm
11
Atomic Weight
102.91 amu
99+
231.04 amu
24
Atomic Volume
8.30 cm3/mol
99+
15.00 cm3/mol
34
Adjacent Atomic Numbers
Valence Electron Potential
64.00 (-eV)
22
92.00 (-eV)
11
Lattice Constant
380.34 pm
27
392.50 pm
23
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
12.41 g/cm3
28
15.37 g/cm3
20
Density When Liquid (at m.p.)
10.70 g/cm3
14
Not Available
Tensile Strength
951.00 MPa
5
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 2000 K
0.02 (Pa)
19
Not Available
Elasticity properties
Shear Modulus
150.00 GPa
6
Not Available
Bulk Modulus
275.00 GPa
5
Not Available
Young's Modulus
380.00 GPa
5
Not Available
Poisson Ratio
0.26
22
Not Available
Other Mechanical Properties
Malleable
Unknown
Magnetic Properties
Magnetic Characteristics
Specific Gravity
12.41
20
15.37
12
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
43.30 nΩ·m
99+
177.00 nΩ·m
21
Electrical Conductivity
0.21 106/cm Ω
8
0.05 106/cm Ω
34
Electron Affinity
109.70 kJ/mol
7
Not Available
Thermal Properties
Specific Heat
0.24 J/(kg K)
22
0.12 J/(kg K)
40
Molar Heat Capacity
24.98 J/mol·K
99+
Not Available
Thermal Conductivity
150.00 W/m·K
9
47.00 W/m·K
32
Critical Temperature
Not Available
Not Available
Thermal Expansion
8.20 µm/(m·K)
99+
9.90 µm/(m·K)
40
Enthalpy
Enthalpy of Vaporization
495.40 kJ/mol
12
Not Available
Enthalpy of Fusion
21.76 kJ/mol
10
12.34 kJ/mol
28
Enthalpy of Atomization
556.50 kJ/mol
12
Not Available
Standard Molar Entropy
31.50 J/mol.K
99+
198.10 J/mol.K
1
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