Erbium Promethium Comparison
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
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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