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Chromium vs Neptunium

Chromium
Neptunium
Neptunium vs Chromium


Periodic Table
Symbol
Cr  
Np  
Group Number
6  
12
3  
15
Period Number
4  
7  
Block
d block  
f block  
Element Family
Transition Metal  
Actinide  
CAS Number
7440473  
39
7439998  
99+
Space Group Name
Im_ 3m  
Pnma  
Space Group Number
229.00  
2
62.00  
14
Facts
Interesting Facts
  • Chromium is highly reactive, hence it is not found free in nature.
  • Ores of Chromites mineral are the major source of Chromium metal.
  • Almost 90% leather tanning is done with the help of chromium.
  
Neptunium was the first transuranium element to be discovered.  
Sources
Found in Minerals, Mining, Ores of metals, Ores of Minerals  
Made by Bombarding Uranium with Neutrons, Ores of metals  
History
  
  
Who Discovered
Louis Nicolas Vauquelin  
Edwin McMillan and Philip H. Abelson  
Discovery
In Between 1797 - 1798  
In 1940  
Abundance
  
  
Abundance In Universe
0.00 %  
8
0.00 %  
40
Abundance In Sun
0.00 %  
7
0.00 %  
26
Abundance In Meteorites
0.30 %  
7
0.00 %  
99+
Abundance In Earth's Crust
0.01 %  
13
0.00 %  
99+
Abundance In Oceans
0.00 %  
16
-  
Abundance In Humans
0.00 %  
19
0.00 %  
24
Uses
Uses & Benefits
  • It is used to harden the steel and produces a stainless steel and other various alloys.
  • It is also used to give proper finish to polished mirrors. Its chromium plates are used in bathroom fittings.
  
  • Currently known uses of Neptunium metal are limited to research purpose only.
  • Neptunium’s isotope neptunium-237 is used as a neutron detectors.
  
Industrial Uses
Automobile Industry, Chemical Industry  
-  
Medical Uses
-  
-  
Other Uses
Alloys  
Alloys, Nuclear Research, Research Purposes  
Biological Properties
  
  
Toxicity
Highly Toxic  
Toxic  
Present in Human Body
Yes  
No  
In Blood
0.11 Blood/mg dm-3  
12
0.00 Blood/mg dm-3  
40
In Bone
0.33 p.p.m.  
25
0.00 p.p.m.  
99+
Physical
Melting Point
1,857.00 °C  
14
640.00 °C  
99+
Boiling Point
2,672.00 °C  
99+
3,902.00 °C  
13
Appearance
  
  
Physical State
Solid  
Solid  
Color
Silver  
Silver  
Luster
Metallic  
Metallic  
Hardness
  
  
Mohs Hardness
8.50  
1
6.00  
6
Brinell Hardness
687.00 MPa  
18
622.00 MPa  
23
Vickers Hardness
1,060.00 MPa  
17
640.00 MPa  
23
Speed of Sound
5,940.00 m/s  
8
2,260.00 m/s  
99+
Optical Properties
  
  
Refractive Index
2.97  
2
1.30  
99+
Reflectivity
70.00 %  
13
64.00 %  
19
Allotropes
No  
No  
α Allotropes
-  
-  
β Allotropes
-  
-  
γ Allotropes
-  
-  
Chemical
Chemical Formula
Cr  
Np  
Isotopes
  
  
Known Isotopes
21  
18
20  
19
Electronegativity
  
  
Pauling Electronegativity
1.66  
19
1.36  
30
Sanderson Electronegativity
1.66  
17
1.36  
23
Allred Rochow Electronegativity
1.56  
11
1.22  
27
Mulliken-Jaffe Electronegativity
1.66  
19
1.36  
31
Allen Electronegativity
1.65  
22
1.36  
37
Electropositivity
  
  
Pauling Electropositivity
2.34  
36
2.64  
25
Ionization Energies
  
  
1st Energy Level
26,130.00 kJ/mol  
1
604.50 kJ/mol  
99+
2nd Energy Level
28,750.00 kJ/mol  
1
1,128.00 kJ/mol  
99+
3rd Energy Level
34,230.00 kJ/mol  
1
1,997.00 kJ/mol  
99+
4th Energy Level
37,066.00 kJ/mol  
1
3,242.00 kJ/mol  
99+
5th Energy Level
97,510.00 kJ/mol  
1
6,180.00 kJ/mol  
99+
6th Energy Level
105,800.00 kJ/mol  
1
5,785.00 kJ/mol  
99+
7th Energy level
114,300.00 kJ/mol  
1
6,040.00 kJ/mol  
99+
8th Energy Level
125,300.00 kJ/mol  
1
6,040.00 kJ/mol  
99+
9th Energy Level
134,700.00 kJ/mol  
1
6,180.00 kJ/mol  
99+
10th Energy Level
144,300.00 kJ/mol  
1
6,180.00 kJ/mol  
99+
11th Energy Level
26,130.00 kJ/mol  
12
6,180.00 kJ/mol  
99+
12th Energy Level
28,750.00 kJ/mol  
36
61,800.00 kJ/mol  
13
13th Energy Level
34,230.00 kJ/mol  
10
6,180.00 kJ/mol  
40
14th Energy Level
37,066.00 kJ/mol  
12
6,180.00 kJ/mol  
29
15th Energy Level
97,510.00 kJ/mol  
2
60,600.00 kJ/mol  
99+
16th Energy Level
105,800.00 kJ/mol  
2
60,420.00 kJ/mol  
31
17th Energy Level
114,300.00 kJ/mol  
3
604.00 kJ/mol  
99+
18th Energy Level
125,300.00 kJ/mol  
4
6,040.00 kJ/mol  
99+
19th Energy Level
134,700.00 kJ/mol  
5
604.50 kJ/mol  
99+
20th Energy Level
144,300.00 kJ/mol  
7
604.00 kJ/mol  
99+
21st Energy Level
157,700.00 kJ/mol  
7
6,040.00 kJ/mol  
17
22nd Energy Level
166,090.00 kJ/mol  
6
604.00 kJ/mol  
40
23rd Energy Level
653.80 kJ/mol  
99+
6,040.00 kJ/mol  
18
24th Energy Level
653.80 kJ/mol  
32
604.50 kJ/mol  
99+
25th Energy Level
653.80 kJ/mol  
34
604.00 kJ/mol  
99+
26th Energy Level
653.80 kJ/mol  
33
604.00 kJ/mol  
99+
27th Energy Level
652.90 kJ/mol  
34
604.00 kJ/mol  
99+
28th Energy Level
653.80 kJ/mol  
39
604.00 kJ/mol  
99+
29th Energy Level
653.80 kJ/mol  
40
604.00 kJ/mol  
99+
30th Energy Level
653.80 kJ/mol  
36
604.00 kJ/mol  
99+
Electrochemical Equivalent
0.32 g/amp-hr  
99+
1.77 g/amp-hr  
99+
Electron Work Function
4.50 eV  
19
4.90 eV  
12
Other Chemical Properties
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility  
Ionization, Radioactive Isotopes, Radioactivity, Solubility  
Atomic
Atomic Number
24  
99+
93  
25
Electron Configuration
[Ar] 3d5 4s1  
[Rn] 5f4 6d1 7s2  
Crystal Structure
Body Centered Cubic (BCC)  
Orthorhombic (ORTH)  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100  
ORTH-Crystal-Structure-of-Neptunium.jpg#100  
Atom
  
  
Number of Protons
24  
99+
93  
25
Number of Neutrons
28  
99+
144  
15
Number of Electrons
24  
99+
93  
25
Radius of an Atom
  
  
Atomic Radius
128.00 pm  
99+
155.00 pm  
32
Covalent Radius
139.00 pm  
99+
190.00 pm  
18
Van der Waals Radius
200.00 pm  
35
221.00 pm  
27
Atomic Weight
52.00 amu  
99+
237.00 amu  
22
Atomic Volume
7.23 cm3/mol  
99+
11.62 cm3/mol  
99+
Adjacent Atomic Numbers
  
  
Previous Element
Vanadium
  
Uranium
  
Next Element
Manganese
  
Plutonium
  
Valence Electron Potential
170.00 (-eV)  
4
96.00 (-eV)  
9
Lattice Constant
291.00 pm  
99+
666.30 pm  
3
Lattice Angles
π/2, π/2, π/2  
π/2, π/2, π/2  
Lattice C/A Ratio
1.86  
4
1.43  
99+
Mechanical
Density
  
  
Density At Room Temperature
7.19 g/cm3  
99+
19.38 g/cm3  
14
Density When Liquid (at m.p.)
6.30 g/cm3  
99+
20.25 g/cm3  
10
Tensile Strength
689.00 MPa  
7
125.00 MPa  
26
Viscosity
0.00  
23
0.00  
25
Vapor Pressure
  
  
Vapor Pressure at 1000 K
0.00 (Pa)  
26
0.00 (Pa)  
22
Vapor Pressure at 2000 K
774.00 (Pa)  
1
0.11 (Pa)  
17
Elasticity properties
  
  
Shear Modulus
115.00 GPa  
9
5.60 GPa  
99+
Bulk Modulus
160.00 GPa  
11
180.00 GPa  
9
Young's Modulus
279.00 GPa  
8
46.00 GPa  
99+
Poisson Ratio
0.21  
33
0.26  
22
Other Mechanical Properties
-  
Ductile  
Magnetic
Magnetic Characteristics
  
  
Specific Gravity
7.19  
99+
20.25  
15
Magnetic Ordering
Antiferromagnetic  
Paramagnetic  
Permeability
0.00 H/m  
17
0.00 H/m  
6
Susceptibility
0.00  
10
0.00  
24
Electrical Properties
  
  
Electrical Property
-  
Conductor  
Resistivity
125.00 nΩ·m  
27
1.22 nΩ·m  
99+
Electrical Conductivity
0.08 106/cm Ω  
30
0.01 106/cm Ω  
99+
Electron Affinity
64.30 kJ/mol  
17
118.60 kJ/mol  
6
Thermal
Specific Heat
0.45 J/(kg K)  
12
0.12 J/(kg K)  
99+
Molar Heat Capacity
23.35 J/mol·K  
99+
29.46 J/mol·K  
10
Thermal Conductivity
93.90 W/m·K  
17
6.30 W/m·K  
99+
Critical Temperature
1,907.00 K  
24
913.00 K  
99+
Thermal Expansion
4.90 µm/(m·K)  
99+
13.30 µm/(m·K)  
35
Enthalpy
  
  
Enthalpy of Vaporization
348.80 kJ/mol  
35
336.00 kJ/mol  
39
Enthalpy of Fusion
15.31 kJ/mol  
20
3.20 kJ/mol  
99+
Enthalpy of Atomization
397.50 kJ/mol  
27
275.30 kJ/mol  
99+
Standard Molar Entropy
23.80 J/mol.K  
99+
64.00 J/mol.K  
21
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