Neptunium Curium Comparison
Periodic Table
Symbol
Np
Cm
Group Number
Not Available
Not Available
Period Number
7
7
Block
f block
f block
Element Family
Actinide
Actinide
CAS Number
7439998
99+
7440519
36
Space Group Name
Pnma
Not Available
Space Group Number
62.00
11
Not Available
Facts
Interesting Facts
Not Available
- Curium metal does not occur free in nature.
- Curium metal is a synthetically produced metal.
Sources
Made by Bombarding Uranium with Neutrons, Ores of metals
Bombarding Plutonium with Helium Ions
History
Who Discovered
Edwin McMillan and Philip H. Abelson
Glenn T. Seaborg, Ralph A. James, Albert Ghiorso
Discovery
In 1940
In 1944
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.
- Curium metal is used to provide power to electrical equipment for space missions.
Industrial Uses
NA
NA
Medical Uses
NA
NA
Other Uses
Alloys, Nuclear Research, Research Purposes
Research Purposes
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+
1,340.00 °C
34
Boiling Point
3,902.00 °C
13
3,110.00 °C
30
Appearance
Physical State
Solid
Solid
Color
Silver
Silver
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
Cm
Isotopes
Known Isotopes
20
19
15
24
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+
581.00 kJ/mol
99+
2nd Energy Level
1,128.00 kJ/mol
99+
1,196.00 kJ/mol
99+
3rd Energy Level
1,997.00 kJ/mol
99+
2,026.00 kJ/mol
99+
4th Energy Level
3,242.00 kJ/mol
99+
3,550.00 kJ/mol
99+
Electrochemical Equivalent
1.77 g/amp-hr
39
3.07 g/amp-hr
16
Electron Work Function
Not Available
Not Available
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
Ionization, Radioactive Isotopes
Atomic Properties
Atomic Number
93
25
96
22
Electron Configuration
[Rn] 5f4 6d1 7s2
[Rn] 5f7 6d1 7s2
Crystal Structure
Orthorhombic (ORTH)
Double Hexagonal Close Packed (DHCP)
Crystal Lattice
ORTH-Crystal-Structure-of-Neptunium.jpg#100
DHCP-Crystal-Structure-of-Curium.jpg#100
Atom
Number of Protons
93
25
96
22
Number of Neutrons
144
14
151
10
Number of Electrons
93
25
96
22
Radius of an Atom
Atomic Radius
155.00 pm
30
174.00 pm
20
Covalent Radius
190.00 pm
18
169.00 pm
26
Van der Waals Radius
221.00 pm
22
200.00 pm
28
Atomic Weight
237.00 amu
22
247.00 amu
18
Atomic Volume
11.62 cm3/mol
99+
18.28 cm3/mol
26
Adjacent Atomic Numbers
Valence Electron Potential
96.00 (-eV)
9
44.50 (-eV)
38
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
13.51 g/cm3
25
Density When Liquid (at m.p.)
Not Available
13.85 g/cm3
10
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
13.51
17
Magnetic Ordering
Paramagnetic
Antiferromagnetic
Electrical Properties
Electrical Property
Conductor
Unknown
Resistivity
1.22 nΩ·m
99+
1.25 nΩ·m
99+
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+
15.00 kJ/mol
21
Standard Molar Entropy
Not Available
Not Available
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