Symbol
Pr
  
Rh
  
Group Number
Not Available
  
Period Number
6
  
5
  
Block
f block
  
d block
  
Element Family
Lanthanide
  
Transition Metal
  
Space Group Name
P63/mmc
  
Fm_ 3m
  
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 Sun
~0.0000001 %
  
26
~0.0000002 %
  
25
Abundance In Earth's Crust
Abundance In Oceans
Not Available
  
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
  
Melting Point
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
  
Vickers Hardness
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
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Pr
  
Rh
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
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+
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
  
Anti Corrosion, Ionization, Radioactive Isotopes
  
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
  
  
Radius of an Atom
  
  
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 Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
6.77 g/cm3
  
99+
12.41 g/cm3
  
28
Density When Liquid (at m.p.)
10.70 g/cm3
  
14
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile, Malleable
  
Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
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
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+