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