Praseodymium vs Rhodium
Periodic Table
Symbol
Pr
Rh
Group Number
Not Available
9
9
Period Number
6
5
Block
f block
d block
Element Family
Lanthanide
Transition Metal
CAS Number
7440100
99+
7440166
99+
Space Group Name
P63/mmc
Fm_ 3m
Space Group Number
194.00
5
225.00
2
Facts
Interesting Facts
- Praseodymium metal is synthetically produced metal.
- Praseodymium is used as possible fuel for radioactive generators.
- 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 Minerals, Mining, Ores of Minerals
Earth's crust, Found As a By-product, Found in Minerals, Mining
History
Who Discovered
Not Available
William Hyde Wollaston
Discovery
In 1885
In 1804
Abundance
Abundance In Universe
2 * 10-7 %
22
6 * 10-8 %
26
Abundance In Sun
~0.0000001 %
26
~0.0000002 %
25
Abundance In Meteorites
0.00 %
40
0.00 %
36
Abundance In Earth's Crust
0.00 %
27
0.00 %
99+
Abundance In Oceans
0.00 %
39
Not Available
Uses
Uses & Benefits
- The main use of Praseodymium include alloys. Praseodymium –Magnesium alloy is used in aircraft engines due to its high strength.
- This metal is also used while making a permanent magnets.
- 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
Chemical Industry
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Medical Uses
NA
NA
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Moderately Toxic
NA
Present in Human Body
No
No
Physical Properties
Melting Point
935.00 °C
99+
1,966.00 °C
12
Boiling Point
3,130.00 °C
27
3,727.00 °C
17
Appearance
Physical State
Solid
Solid
Color
Grayish White
Silvery White
Luster
Metallic
Metallic
Hardness
Mohs Hardness
Not Available
6.00
6
Brinell Hardness
481.00 MPa
24
980.00 MPa
9
Vickers Hardness
400.00 MPa
25
1,100.00 MPa
9
Speed of Sound
2,280.00 m/s
40
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
Pr
Rh
Isotopes
Known Isotopes
31
8
16
23
Electronegativity
Pauling Electronegativity
1.13
99+
2.28
3
Allred Rochow Electronegativity
1.07
32
1.45
16
Allen Electronegativity
Not Available
1.56
24
Electropositivity
Pauling Electropositivity
2.87
12
1.72
99+
Ionization Energies
1st Energy Level
527.00 kJ/mol
99+
719.70 kJ/mol
29
2nd Energy Level
1,020.00 kJ/mol
99+
1,740.00 kJ/mol
26
3rd Energy Level
2,086.00 kJ/mol
99+
2,997.00 kJ/mol
27
4th Energy Level
3,761.00 kJ/mol
99+
Not Available
5th Energy Level
5,551.00 kJ/mol
29
Not Available
Electrochemical Equivalent
1.75 g/amp-hr
40
1.28 g/amp-hr
99+
Electron Work Function
2.70 eV
99+
4.98 eV
6
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
Anti Corrosion, Ionization, Radioactive Isotopes
Atomic Properties
Atomic Number
59
99+
45
99+
Electron Configuration
[Xe] 4f3 6s2
[Kr] 4d8 5s1
Crystal Structure
Hexagonal Close Packed (HCP)
Face Centered Cubic (FCC)
Crystal Lattice
HCP-Crystal-Structure-of-Praseodymium.jpg#100
FCC-Crystal-Structure-of-Rhodium.jpg#100
Atom
Number of Protons
59
99+
45
99+
Number of Neutrons
82
99+
58
99+
Number of Electrons
59
99+
45
99+
Radius of an Atom
Atomic Radius
182.00 pm
11
134.00 pm
99+
Covalent Radius
203.00 pm
9
142.00 pm
99+
Van der Waals Radius
239.00 pm
14
200.00 pm
28
Atomic Weight
140.91 amu
99+
102.91 amu
99+
Atomic Volume
20.80 cm3/mol
15
8.30 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
42.64 (-eV)
99+
64.00 (-eV)
22
Lattice Constant
367.25 pm
29
380.34 pm
27
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.61
4
Not Available
Mechanical Properties
Density
Density At Room Temperature
6.77 g/cm3
99+
12.41 g/cm3
28
Density When Liquid (at m.p.)
6.50 g/cm3
39
10.70 g/cm3
14
Tensile Strength
Not Available
951.00 MPa
5
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
25
Not Available
Vapor Pressure at 2000 K
13.20 (Pa)
7
0.02 (Pa)
19
Elasticity properties
Shear Modulus
14.80 GPa
39
150.00 GPa
6
Bulk Modulus
28.80 GPa
40
275.00 GPa
5
Young's Modulus
37.30 GPa
99+
380.00 GPa
5
Poisson Ratio
0.28
16
0.26
22
Other Mechanical Properties
Ductile, Malleable
Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
6.77
99+
12.41
20
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
0.70 nΩ·m
99+
43.30 nΩ·m
99+
Electrical Conductivity
0.01 106/cm Ω
99+
0.21 106/cm Ω
8
Electron Affinity
50.00 kJ/mol
21
109.70 kJ/mol
7
Thermal Properties
Specific Heat
0.19 J/(kg K)
32
0.24 J/(kg K)
22
Molar Heat Capacity
27.20 J/mol·K
18
24.98 J/mol·K
99+
Thermal Conductivity
12.50 W/m·K
99+
150.00 W/m·K
9
Critical Temperature
Not Available
Not Available
Thermal Expansion
6.70 µm/(m·K)
99+
8.20 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
296.80 kJ/mol
29
495.40 kJ/mol
12
Enthalpy of Fusion
6.89 kJ/mol
99+
21.76 kJ/mol
10
Enthalpy of Atomization
368.00 kJ/mol
24
556.50 kJ/mol
12
Standard Molar Entropy
73.20 J/mol.K
10
31.50 J/mol.K
99+
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