Home

Transition Metals + -

Actinide Metals + -

Lanthanide Metals + -

Post-Transition Metals + -

Alkaline Earth Metals + -

Compare Metals


Neptunium vs Mendelevium


Mendelevium vs Neptunium


Periodic Table

Symbol
Np   
Md   

Group Number
Not Available   
Not Available   

Period Number
7   
7   

Block
f block   
f block   

Element Family
Actinide   
Actinide   

CAS Number
7439998   
99+
7440111   
99+

Space Group Name
Pnma   
Not Available   

Space Group Number
62.00   
11
Not Available   

Facts

Interesting Facts
Not Available   
  • Mendelevium metal is synthetically produced metal.
  • Mendelevium metal has been produced in only trace amount.
  

Sources
Made by Bombarding Uranium with Neutrons, Ores of metals   
Bombarding Einsteinium with Helium Ions   

History
  
  

Who Discovered
Edwin McMillan and Philip H. Abelson   
Lawrence Berkeley National Laboratory   

Discovery
In 1940   
In 1955   

Abundance
  
  

Uses

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.
  
  • Currently known uses of Mendelevium metal are limited to research purpose only.
  

Industrial Uses
NA   
NA   

Medical Uses
NA   
NA   

Other Uses
Alloys, Nuclear Research, Research Purposes   
NA   

Biological Properties
  
  

Toxicity
Toxic   
Unknown   

Present in Human Body
No   
No   

In Blood
0.00 Blood/mg dm-3   
37
0.00 Blood/mg dm-3   
37

In Bone
0.00 p.p.m.   
36
0.00 p.p.m.   
36

Physical Properties

Melting Point
640.00 °C   
99+
827.00 °C   
99+

Boiling Point
3,902.00 °C   
13
Not Available   

Appearance
  
  

Physical State
Solid   
Solid   

Color
Silver   
Unknown   

Luster
Metallic   
Metallic   

Hardness
  
  

Speed of Sound
Not Available   
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
Np   
Md   

Isotopes
  
  

Known Isotopes
20   
19
16   
23

Electronegativity
  
  

Pauling Electronegativity
1.36   
29
1.30   
32

Allred Rochow Electronegativity
1.22   
26
1.20   
27

Electropositivity
  
  

Pauling Electropositivity
2.64   
25
2.70   
22

Ionization Energies
  
  

1st Energy Level
604.50 kJ/mol   
99+
635.00 kJ/mol   
99+

2nd Energy Level
1,128.00 kJ/mol   
99+
1,235.00 kJ/mol   
99+

3rd Energy Level
1,997.00 kJ/mol   
99+
2,470.00 kJ/mol   
99+

4th Energy Level
3,242.00 kJ/mol   
99+
3,840.00 kJ/mol   
99+

Electrochemical Equivalent
1.77 g/amp-hr   
39
3.21 g/amp-hr   
12

Electron Work Function
Not Available   
Not Available   

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

Atomic Properties

Atomic Number
93   
25
101   
17

Electron Configuration
[Rn] 5f4 6d1 7s2   
[Rn] 5f13 7s2   

Crystal Structure
Orthorhombic (ORTH)   
Not Known   

Crystal Lattice
ORTH-Crystal-Structure-of-Neptunium.jpg#100   
Unknown-Crystal-Structure-of-Mendelevium.jpg#100   

Atom
  
  

Number of Protons
93   
25
101   
17

Number of Neutrons
144   
14
157   
7

Number of Electrons
93   
25
101   
17

Radius of an Atom
  
  

Atomic Radius
155.00 pm   
30
Not Available   

Covalent Radius
190.00 pm   
18
Not Available   

Van der Waals Radius
221.00 pm   
22
246.00 pm   
8

Atomic Weight
237.00 amu   
22
258.00 amu   
14

Atomic Volume
11.62 cm3/mol   
99+
Not Available   

Adjacent Atomic Numbers
  
  

Previous Element
Uranium
  
Fermium
  

Next Element
Plutonium
  
Nobelium
  

Valence Electron Potential
96.00 (-eV)   
9
Not Available   

Lattice Constant
666.30 pm   
3
Not Available   

Lattice Angles
π/2, π/2, π/2   
NA   

Lattice C/A Ratio
Not Available   
Not Available   

Mechanical Properties

Density
  
  

Density At Room Temperature
19.38 g/cm3   
14
Not Available   

Tensile Strength
125.00 MPa   
14
Not Available   

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Vapor Pressure at 2000 K
0.11 (Pa)   
17
Not Available   

Elasticity properties
  
  

Poisson Ratio
Not Available   
Not Available   

Other Mechanical Properties
Ductile   
Unknown   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
20.25   
6
Not Available   

Magnetic Ordering
Paramagnetic   
Unknown   

Electrical Properties
  
  

Electrical Property
Conductor   
Unknown   

Resistivity
1.22 nΩ·m   
99+
Not Available   

Electrical Conductivity
0.01 106/cm Ω   
99+
Not Available   

Thermal Properties

Specific Heat
0.12 J/(kg K)   
40
Not Available   

Molar Heat Capacity
29.46 J/mol·K   
8
Not Available   

Thermal Conductivity
6.30 W/m·K   
99+
Not Available   

Critical Temperature
Not Available   
Not Available   

Thermal Expansion
Not Available   
Not Available   

Enthalpy
  
  

Enthalpy of Fusion
3.20 kJ/mol   
99+
Not Available   

Standard Molar Entropy
Not Available   
Not Available   

Periodic Table >>
<< All

Compare Actinide Series

Actinide Metals

Actinide Metals

» More Actinide Metals

Compare Actinide Series

» More Compare Actinide Series