Symbol
Er
  
Md
  
Group Number
Not Available
  
Not Available
  
Period Number
6
  
7
  
Block
f block
  
f block
  
Element Family
Lanthanide
  
Actinide
  
Space Group Name
P63/mmc
  
Not Available
  
Space Group Number
Not Available
  
Interesting Facts
- Erbium metal is used as alloyed with Vanadium to make it softer.
- Recent studies shows that it is helpful for metabolism.
  
- Mendelevium metal is synthetically produced metal.
- Mendelevium metal has been produced in only trace amount.
  
Sources
Mining
  
Bombarding Einsteinium with Helium Ions
  
History
  
  
Who Discovered
Carl Gustaf Mosander
  
Lawrence Berkeley National Laboratory
  
Discovery
In 1842
  
In 1955
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~0.0000001 %
  
26
~-9999 %
  
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
Abundance In Oceans
Not Available
  
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.
  
- Currently known uses of Mendelevium metal are limited to research purpose only.
  
Industrial Uses
Chemical Industry
  
NA
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
NA
  
Biological Properties
  
  
Toxicity
Mildly Toxic
  
Unknown
  
Present in Human Body
No
  
No
  
In Blood
Not Available
  
0.00 Blood/mg dm-3
  
37
In Bone
Not Available
  
0.00 p.p.m.
  
36
Melting Point
1,522.00 °C
  
28
Boiling Point
2,510.00 °C
  
99+
Not Available
  
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery White
  
Unknown
  
Luster
Lustrous
  
Metallic
  
Hardness
  
  
Brinell Hardness
Not Available
  
Vickers Hardness
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 Formula
Er
  
Md
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
589.30 kJ/mol
  
99+
635.00 kJ/mol
  
99+
2nd Energy Level
1,150.00 kJ/mol
  
99+
1,235.00 kJ/mol
  
99+
3rd Energy Level
2,194.00 kJ/mol
  
99+
2,470.00 kJ/mol
  
99+
4th Energy Level
4,120.00 kJ/mol
  
33
3,840.00 kJ/mol
  
99+
Electrochemical Equivalent
2.08 g/amp-hr
  
28
3.21 g/amp-hr
  
12
Electron Work Function
Not Available
  
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes, Radioactivity
  
Electron Configuration
[Xe] 4f12 6s2
  
[Rn] 5f13 7s2
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Not Known
  
Crystal Lattice
HCP-Crystal-Structure-of-Erbium.jpg#100
  
Unknown-Crystal-Structure-of-Mendelevium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Radius
Not Available
  
Covalent Radius
Not Available
  
Van der Waals Radius
Not Available
  
Atomic Weight
167.26 amu
  
99+
Atomic Volume
18.40 cm3/mol
  
25
Not Available
  
Adjacent Atomic Numbers
  
  
Valence Electron Potential
49.00 (-eV)
  
29
Not Available
  
Lattice Constant
Not Available
  
Lattice Angles
π/2, π/2, 2 π/3
  
NA
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
9.07 g/cm
3
  
99+
Not Available
  
Density When Liquid (at m.p.)
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
Malleable
  
Unknown
  
Magnetic Characteristics
  
  
Specific Gravity
Not Available
  
Magnetic Ordering
Paramagnetic
  
Unknown
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Unknown
  
Resistivity
Not Available
  
Electrical Conductivity
0.01 10
6/cm Ω
  
99+
Not Available
  
Electron Affinity
50.00 kJ/mol
  
21
Not Available
  
Specific Heat
0.17 J/(kg K)
  
34
Not Available
  
Molar Heat Capacity
28.12 J/mol·K
  
11
Not Available
  
Thermal Conductivity
14.50 W/m·K
  
99+
Not Available
  
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
12.20 µm/(m·K)
  
31
Not Available
  
Enthalpy
  
  
Enthalpy of Vaporization
261.00 kJ/mol
  
35
Not Available
  
Enthalpy of Fusion
17.20 kJ/mol
  
15
Not Available
  
Enthalpy of Atomization
314.00 kJ/mol
  
33
Not Available
  
Standard Molar Entropy
73.10 J/mol.K
  
11
Not Available