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Erbium vs Promethium


Promethium vs Erbium


Periodic Table

Symbol
Er   
Pm   

Group Number
Not Available   
Not Available   

Period Number
6   
6   

Block
f block   
f block   

Element Family
Lanthanide   
Lanthanide   

CAS Number
7440520   
35
7440122   
99+

Space Group Name
P63/mmc   
Not Available   

Space Group Number
194.00   
5
Not Available   

Facts

Interesting Facts
  • Erbium metal is used as alloyed with Vanadium to make it softer.
  • Recent studies shows that it is helpful for metabolism.
  
  • Promethium metal found in Pitchblende.
  • Promethium metal is highly radioactive metal.
  

Sources
Mining   
Found in Minerals, Mining   

History
  
  

Who Discovered
Carl Gustaf Mosander   
Chien Shiung Wu, Emilio Segrè, Hans Bethe   

Discovery
In 1842   
In 1942   

Abundance
  
  

Abundance In Universe
2 * 10-7 %   
22
Not Available   

Abundance In Sun
~0.0000001 %   
26
~-9999 %   

Abundance In Meteorites
0.00 %   
36
Not Available   

Abundance In Earth's Crust
0.00 %   
32
Not Available   

Abundance In Oceans
0.00 %   
36
Not Available   

Uses

Uses & Benefits
  • It has a tendency to get tarnished in the open air, but when alloyed with elements like erbium, vanadium, its hardness levels decreases.
  • Its compounds like Erbium oxide is used in safety glasses of welders and metal workers.
  
  • It is used for research purpose. Very small amount of this metal is used in atomic batteries.
  • Its radioactive decay is used for a phosphor to give off light. The light emitted is converted into electricity.
  

Industrial Uses
Chemical Industry   
NA   

Medical Uses
NA   
NA   

Other Uses
Alloys   
NA   

Biological Properties
  
  

Toxicity
Mildly Toxic   
Non Toxic   

Present in Human Body
No   
No   

In Blood
Not Available   
0.00 Blood/mg dm-3   
37

Physical Properties

Melting Point
1,522.00 °C   
28
1,042.00 °C   
99+

Boiling Point
2,510.00 °C   
99+
3,000.00 °C   
31

Appearance
  
  

Physical State
Solid   
Solid   

Color
Silvery White   
Unknown   

Luster
Lustrous   
Metallic   

Hardness
  
  

Brinell Hardness
814.00 MPa   
11
Not Available   

Vickers Hardness
589.00 MPa   
19
Not Available   

Speed of Sound
2,830.00 m/s   
28
Not Available   

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
Er   
Pm   

Isotopes
  
  

Known Isotopes
31   
8
27   
12

Electronegativity
  
  

Pauling Electronegativity
1.24   
36
Not Available   

Allred Rochow Electronegativity
1.11   
29
1.07   
32

Electropositivity
  
  

Pauling Electropositivity
2.76   
18
Not Available   

Ionization Energies
  
  

1st Energy Level
589.30 kJ/mol   
99+
540.00 kJ/mol   
99+

2nd Energy Level
1,150.00 kJ/mol   
99+
1,050.00 kJ/mol   
99+

3rd Energy Level
2,194.00 kJ/mol   
99+
2,150.00 kJ/mol   
99+

4th Energy Level
4,120.00 kJ/mol   
33
3,970.00 kJ/mol   
38

Electrochemical Equivalent
2.08 g/amp-hr   
28
1.80 g/amp-hr   
36

Electron Work Function
Not Available   
Not Available   

Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility   
Ionization, Radioactive Isotopes, Solubility   

Atomic Properties

Atomic Number
68   
99+
61   
99+

Electron Configuration
[Xe] 4f12 6s2   
[Xe] 4f5 6s2   

Crystal Structure
Hexagonal Close Packed (HCP)   
Double Hexagonal Close Packed (DHCP)   

Crystal Lattice
HCP-Crystal-Structure-of-Erbium.jpg#100   
DHCP-Crystal-Structure-of-Promethium.jpg#100   

Atom
  
  

Number of Protons
68   
99+
61   
99+

Number of Neutrons
99   
33
84   
40

Number of Electrons
68   
99+
61   
99+

Radius of an Atom
  
  

Atomic Radius
176.00 pm   
18
183.00 pm   
10

Covalent Radius
189.00 pm   
19
199.00 pm   
12

Van der Waals Radius
Not Available   
236.00 pm   
16

Atomic Weight
167.26 amu   
99+
145.00 amu   
99+

Atomic Volume
18.40 cm3/mol   
25
22.39 cm3/mol   
12

Adjacent Atomic Numbers
  
  

Previous Element
Holmium
  
Neodymium
  

Next Element
Thulium
  
Samarium
  

Valence Electron Potential
49.00 (-eV)   
29
44.10 (-eV)   
39

Lattice Constant
355.88 pm   
39
Not Available   

Lattice Angles
π/2, π/2, 2 π/3   
Unknown   

Lattice C/A Ratio
1.57   
17
Not Available   

Mechanical Properties

Density
  
  

Density At Room Temperature
9.07 g/cm3   
99+
7.26 g/cm3   
99+

Density When Liquid (at m.p.)
8.86 g/cm3   
23
Not Available   

Tensile Strength
Not Available   
Not Available   

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Vapor Pressure at 1000 K
0.00 (Pa)   
20
Not Available   

Elasticity properties
  
  

Shear Modulus
28.30 GPa   
25
18.00 GPa   
36

Bulk Modulus
44.40 GPa   
27
33.00 GPa   
36

Young's Modulus
69.90 GPa   
29
46.00 GPa   
38

Poisson Ratio
0.24   
28
0.28   
17

Other Mechanical Properties
Malleable   
NA   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
9.07   
32
7.26   
99+

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Conductor   
Conductor   

Resistivity
0.86 nΩ·m   
99+
0.75 nΩ·m   
99+

Electrical Conductivity
0.01 106/cm Ω   
99+
Not Available   

Electron Affinity
50.00 kJ/mol   
21
50.00 kJ/mol   
21

Thermal Properties

Specific Heat
0.17 J/(kg K)   
34
0.18 J/(kg K)   
33

Molar Heat Capacity
28.12 J/mol·K   
11
Not Available   

Thermal Conductivity
14.50 W/m·K   
99+
17.90 W/m·K   
99+

Critical Temperature
Not Available   
Not Available   

Thermal Expansion
12.20 µm/(m·K)   
31
9.00 µm/(m·K)   
99+

Enthalpy
  
  

Enthalpy of Vaporization
261.00 kJ/mol   
35
Not Available   

Enthalpy of Fusion
17.20 kJ/mol   
15
7.50 kJ/mol   
99+

Enthalpy of Atomization
314.00 kJ/mol   
33
310.00 kJ/mol   
34

Standard Molar Entropy
73.10 J/mol.K   
11
Not Available   

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