Lanthanum vs Praseodymium
Periodic Table
Symbol
La
Pr
Group Number
Not Available
Not Available
Period Number
6
6
Block
f block
f block
Element Family
Lanthanide
Lanthanide
CAS Number
7439910
99+
7440100
99+
Space Group Name
P63/mmc
P63/mmc
Space Group Number
194.00
5
194.00
5
Facts
Interesting Facts
- Lanthanum metal is highly malleable, ductile and sectile.
- If exposed to air Lanthanum metal oxidizes rapidly.
- Praseodymium metal is synthetically produced metal.
- Praseodymium is used as possible fuel for radioactive generators.
Sources
Found in Minerals, Mining, Ores of Minerals
Found in Minerals, Mining, Ores of Minerals
History
Who Discovered
Carl Gustaf Mosander
Not Available
Discovery
In 1838
In 1885
Abundance
Abundance In Universe
2 * 10-7 %
22
2 * 10-7 %
22
Abundance In Sun
~0.0000002 %
25
~0.0000001 %
26
Abundance In Meteorites
0.00 %
32
0.00 %
40
Abundance In Earth's Crust
0.00 %
19
0.00 %
27
Abundance In Oceans
0.00 %
29
0.00 %
39
Uses
Uses & Benefits
- It has no commercial uses, but its alloys are in high demand. Lanthanum and Nickel alloy is used for the hydrogen gas storage.
- The best-known use for mischmetal alloy of Lanthanum is; as a ‘flints’ for cigarette lighters.
- 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.
Industrial Uses
Electrical Industry, Electronic Industry
Chemical Industry
Medical Uses
NA
NA
Other Uses
Alloys, Mirror Manufacturing
Alloys
Biological Properties
Toxicity
Low Toxic
Moderately Toxic
Present in Human Body
Yes
No
In Bone
0.08 p.p.m.
24
Not Available
Physical Properties
Melting Point
920.00 °C
99+
935.00 °C
99+
Boiling Point
3,469.00 °C
18
3,130.00 °C
27
Appearance
Physical State
Solid
Solid
Color
Silvery White
Grayish White
Luster
NA
Metallic
Hardness
Mohs Hardness
2.50
14
Not Available
Brinell Hardness
350.00 MPa
30
481.00 MPa
24
Vickers Hardness
360.00 MPa
26
400.00 MPa
25
Speed of Sound
2,475.00 m/s
37
2,280.00 m/s
40
Optical Properties
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
La
Pr
Isotopes
Known Isotopes
31
8
31
8
Electronegativity
Pauling Electronegativity
1.10
99+
1.13
99+
Allred Rochow Electronegativity
1.08
31
1.07
32
Electropositivity
Pauling Electropositivity
2.90
10
2.87
12
Ionization Energies
1st Energy Level
538.10 kJ/mol
99+
527.00 kJ/mol
99+
2nd Energy Level
1,067.00 kJ/mol
99+
1,020.00 kJ/mol
99+
3rd Energy Level
1,850.30 kJ/mol
99+
2,086.00 kJ/mol
99+
4th Energy Level
4,819.00 kJ/mol
22
3,761.00 kJ/mol
99+
5th Energy Level
5,940.00 kJ/mol
25
5,551.00 kJ/mol
29
Electrochemical Equivalent
1.73 g/amp-hr
99+
1.75 g/amp-hr
40
Electron Work Function
3.50 eV
31
2.70 eV
99+
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Ionization, Radioactive Isotopes
Atomic Properties
Atomic Number
57
99+
59
99+
Electron Configuration
[Xe] 5d2 6s2
[Xe] 4f3 6s2
Crystal Structure
Double Hexagonal Close Packed (DHCP)
Hexagonal Close Packed (HCP)
Crystal Lattice
DHCP-Crystal-Structure-of-Lanthanum.jpg#100
HCP-Crystal-Structure-of-Praseodymium.jpg#100
Atom
Number of Protons
57
99+
59
99+
Number of Neutrons
82
99+
82
99+
Number of Electrons
57
99+
59
99+
Radius of an Atom
Atomic Radius
187.00 pm
8
182.00 pm
11
Covalent Radius
207.00 pm
6
203.00 pm
9
Van der Waals Radius
240.00 pm
13
239.00 pm
14
Atomic Weight
138.91 amu
99+
140.91 amu
99+
Atomic Volume
20.73 cm3/mol
16
20.80 cm3/mol
15
Adjacent Atomic Numbers
Valence Electron Potential
40.71 (-eV)
99+
42.64 (-eV)
99+
Lattice Constant
377.20 pm
28
367.25 pm
29
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, 2 π/3
Lattice C/A Ratio
1.62
2
1.61
4
Mechanical Properties
Density
Density At Room Temperature
6.16 g/cm3
99+
6.77 g/cm3
99+
Density When Liquid (at m.p.)
5.94 g/cm3
99+
6.50 g/cm3
39
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
0.00 (Pa)
25
Vapor Pressure at 2000 K
0.98 (Pa)
15
13.20 (Pa)
7
Elasticity properties
Shear Modulus
14.30 GPa
40
14.80 GPa
39
Bulk Modulus
27.90 GPa
99+
28.80 GPa
40
Young's Modulus
36.60 GPa
99+
37.30 GPa
99+
Poisson Ratio
0.28
17
0.28
16
Other Mechanical Properties
Ductile
Ductile, Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
6.17
99+
6.77
99+
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
615.00 nΩ·m
7
0.70 nΩ·m
99+
Electrical Conductivity
0.01 106/cm Ω
99+
0.01 106/cm Ω
99+
Electron Affinity
48.00 kJ/mol
23
50.00 kJ/mol
21
Thermal Properties
Specific Heat
0.19 J/(kg K)
32
0.19 J/(kg K)
32
Molar Heat Capacity
27.11 J/mol·K
21
27.20 J/mol·K
18
Thermal Conductivity
13.40 W/m·K
99+
12.50 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
12.10 µm/(m·K)
32
6.70 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
399.60 kJ/mol
17
296.80 kJ/mol
29
Enthalpy of Fusion
6.20 kJ/mol
99+
6.89 kJ/mol
99+
Enthalpy of Atomization
431.00 kJ/mol
16
368.00 kJ/mol
24
Standard Molar Entropy
56.90 J/mol.K
23
73.20 J/mol.K
10
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