Neptunium Cerium Comparison
Periodic Table
Symbol
Np
Ce
Group Number
Not Available
Not Available
Period Number
7
6
Block
f block
f block
Element Family
Actinide
Lanthanide
CAS Number
7439998
99+
7440451
99+
Space Group Name
Pnma
P63/mmc
Space Group Number
62.00
11
194.00
5
Facts
Interesting Facts
Not Available
- Cerium is a rare earth metal but still it is not rare at all.
- It’s non-toxic compound Cerium sulfide has a rich red color and it is used as a pigment.
- Cerium metal is also used in Flat screen TVs, light bulb, floodlights, etc.
Sources
Made by Bombarding Uranium with Neutrons, Ores of metals
Found in Minerals, Mining, Ores of Minerals
History
Who Discovered
Edwin McMillan and Philip H. Abelson
Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger
Discovery
In 1940
In 1803
Abundance
Abundance In Universe
Not Available
1 * 10-6 %
16
Abundance In Sun
~-9999 %
~0.0000004 %
23
Abundance In Meteorites
Not Available
0.00 %
27
Abundance In Earth's Crust
Not Available
0.01 %
18
Abundance In Oceans
Not Available
0.00 %
33
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.
- It is used to include flints for cigarette lighters.
- Its compound Cerium (Ill) Oxide is used as a catalyst; it is put inside the walls of the oven as it prevents from the buildup of cooking residues.
Industrial Uses
NA
Chemical Industry
Medical Uses
NA
Medical Research
Other Uses
Alloys, Nuclear Research, Research Purposes
Alloys
Biological Properties
Toxicity
Toxic
Moderately Toxic
Present in Human Body
No
Yes
In Blood
0.00 Blood/mg dm-3
37
0.00 Blood/mg dm-3
30
In Bone
0.00 p.p.m.
36
2.70 p.p.m.
14
Physical Properties
Melting Point
640.00 °C
99+
795.00 °C
99+
Boiling Point
3,902.00 °C
13
3,257.00 °C
23
Appearance
Physical State
Solid
Solid
Color
Silver
Silvery White
Luster
Metallic
Lustrous
Hardness
Mohs Hardness
Not Available
2.50
14
Brinell Hardness
Not Available
186.00 MPa
99+
Vickers Hardness
Not Available
210.00 MPa
32
Speed of Sound
Not Available
2,100.00 m/s
99+
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
Ce
Isotopes
Known Isotopes
20
19
30
9
Electronegativity
Pauling Electronegativity
1.36
29
1.12
99+
Allred Rochow Electronegativity
1.22
26
1.08
31
Electropositivity
Pauling Electropositivity
2.64
25
2.88
11
Ionization Energies
1st Energy Level
604.50 kJ/mol
99+
534.40 kJ/mol
99+
2nd Energy Level
1,128.00 kJ/mol
99+
1,050.00 kJ/mol
99+
3rd Energy Level
1,997.00 kJ/mol
99+
1,949.00 kJ/mol
99+
4th Energy Level
3,242.00 kJ/mol
99+
3,547.00 kJ/mol
99+
5th Energy Level
Not Available
6,325.00 kJ/mol
22
6th Energy Level
Not Available
7,490.00 kJ/mol
21
Electrochemical Equivalent
1.77 g/amp-hr
39
1.74 g/amp-hr
99+
Electron Work Function
Not Available
2.84 eV
39
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
93
25
58
99+
Electron Configuration
[Rn] 5f4 6d1 7s2
[Xe] 4f1 5d1 6s2
Crystal Structure
Orthorhombic (ORTH)
Double Hexagonal Close Packed (DHCP)
Crystal Lattice
ORTH-Crystal-Structure-of-Neptunium.jpg#100
DHCP-Crystal-Structure-of-Cerium.jpg#100
Atom
Number of Protons
93
25
58
99+
Number of Neutrons
144
14
82
99+
Number of Electrons
93
25
58
99+
Radius of an Atom
Atomic Radius
155.00 pm
30
181.80 pm
12
Covalent Radius
190.00 pm
18
204.00 pm
8
Van der Waals Radius
221.00 pm
22
235.00 pm
17
Atomic Weight
237.00 amu
22
140.12 amu
99+
Atomic Volume
11.62 cm3/mol
99+
20.67 cm3/mol
17
Adjacent Atomic Numbers
Valence Electron Potential
96.00 (-eV)
9
41.78 (-eV)
99+
Lattice Constant
666.30 pm
3
362.00 pm
34
Lattice Angles
π/2, π/2, π/2
π/2, π/2, 2 π/3
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
19.38 g/cm3
14
6.77 g/cm3
99+
Density When Liquid (at m.p.)
Not Available
6.55 g/cm3
38
Tensile Strength
125.00 MPa
14
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
0.00 (Pa)
34
Vapor Pressure at 2000 K
0.11 (Pa)
17
1.04 (Pa)
13
Elasticity properties
Shear Modulus
Not Available
13.50 GPa
99+
Bulk Modulus
Not Available
21.50 GPa
99+
Young's Modulus
Not Available
33.60 GPa
99+
Poisson Ratio
Not Available
0.24
27
Other Mechanical Properties
Ductile
Ductile, Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
20.25
6
6.77
99+
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
1.22 nΩ·m
99+
828.00 nΩ·m
3
Electrical Conductivity
0.01 106/cm Ω
99+
0.01 106/cm Ω
99+
Electron Affinity
Not Available
50.00 kJ/mol
21
Thermal Properties
Specific Heat
0.12 J/(kg K)
40
0.19 J/(kg K)
32
Molar Heat Capacity
29.46 J/mol·K
8
26.94 J/mol·K
23
Thermal Conductivity
6.30 W/m·K
99+
11.30 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
Not Available
6.30 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
Not Available
414.00 kJ/mol
16
Enthalpy of Fusion
3.20 kJ/mol
99+
5.46 kJ/mol
99+
Enthalpy of Atomization
Not Available
381.00 kJ/mol
23
Standard Molar Entropy
Not Available
72.00 J/mol.K
12
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