Symbol
Np
  
Er
  
Group Number
Not Available
  
Not Available
  
Period Number
7
  
6
  
Block
f block
  
f block
  
Element Family
Actinide
  
Lanthanide
  
Space Group Name
Pnma
  
P63/mmc
  
Interesting Facts
Not Available
  
- Erbium metal is used as alloyed with Vanadium to make it softer.
- Recent studies shows that it is helpful for metabolism.
  
Sources
Made by Bombarding Uranium with Neutrons, Ores of metals
  
Mining
  
History
  
  
Who Discovered
Edwin McMillan and Philip H. Abelson
  
Carl Gustaf Mosander
  
Discovery
In 1940
  
In 1842
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
~0.0000001 %
  
26
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
Abundance In Oceans
Not Available
  
Uses & Benefits
- Currently known uses of Neptunium metal are limited to research purpose only.
-
Neptunium’s isotope neptunium-237 is used as a neutron detectors.
  
- 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.
  
Industrial Uses
NA
  
Chemical Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys, Nuclear Research, Research Purposes
  
Alloys
  
Biological Properties
  
  
Toxicity
Toxic
  
Mildly Toxic
  
Present in Human Body
No
  
No
  
In Blood
0.00 Blood/mg dm-3
  
37
Not Available
  
In Bone
0.00 p.p.m.
  
36
Not Available
  
Melting Point
1,522.00 °C
  
28
Boiling Point
3,902.00 °C
  
13
2,510.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Silvery White
  
Luster
Metallic
  
Lustrous
  
Hardness
  
  
Brinell Hardness
Not Available
  
Vickers Hardness
Not Available
  
Speed of Sound
Not Available
  
2,830.00 m/s
  
28
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
Np
  
Er
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
604.50 kJ/mol
  
99+
589.30 kJ/mol
  
99+
2nd Energy Level
1,128.00 kJ/mol
  
99+
1,150.00 kJ/mol
  
99+
3rd Energy Level
1,997.00 kJ/mol
  
99+
2,194.00 kJ/mol
  
99+
4th Energy Level
3,242.00 kJ/mol
  
99+
4,120.00 kJ/mol
  
33
Electrochemical Equivalent
1.77 g/amp-hr
  
39
2.08 g/amp-hr
  
28
Electron Work Function
Not Available
  
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
  
Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Rn] 5f4 6d1 7s2
  
[Xe] 4f12 6s2
  
Crystal Structure
Orthorhombic (ORTH)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
ORTH-Crystal-Structure-of-Neptunium.jpg#100
  
HCP-Crystal-Structure-of-Erbium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Van der Waals Radius
Not Available
  
Atomic Weight
167.26 amu
  
99+
Atomic Volume
11.62 cm3/mol
  
99+
18.40 cm3/mol
  
25
Adjacent Atomic Numbers
  
  
Valence Electron Potential
49.00 (-eV)
  
29
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
19.38 g/cm3
  
14
9.07 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Vapor Pressure at 2000 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
Ductile
  
Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Electrical Conductivity
0.01 106/cm Ω
  
99+
0.01 106/cm Ω
  
99+
Electron Affinity
Not Available
  
50.00 kJ/mol
  
21
Specific Heat
0.12 J/(kg K)
  
40
0.17 J/(kg K)
  
34
Molar Heat Capacity
29.46 J/mol·K
  
8
28.12 J/mol·K
  
11
Thermal Conductivity
6.30 W/m·K
  
99+
14.50 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
Not Available
  
12.20 µm/(m·K)
  
31
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
261.00 kJ/mol
  
35
Enthalpy of Fusion
3.20 kJ/mol
  
99+
17.20 kJ/mol
  
15
Enthalpy of Atomization
Not Available
  
314.00 kJ/mol
  
33
Standard Molar Entropy
Not Available
  
73.10 J/mol.K
  
11