Protactinium Chromium Comparison
Periodic Table
Symbol
Pa
Cr
Group Number
Not Available
6
12
Period Number
7
4
Block
f block
d block
Element Family
Actinide
Transition Metal
CAS Number
7440133
99+
7440473
39
Space Group Name
I4/mmm
Im_ 3m
Space Group Number
139.00
8
229.00
1
Facts
Interesting Facts
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
- 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.
Sources
Found in Uranium Ores, Mining, Ores of metals
Found in Minerals, Mining, Ores of metals, Ores of Minerals
History
Who Discovered
William Crookes
Louis Nicolas Vauquelin
Discovery
In 1900
In Between 1797 - 1798
Abundance
Abundance In Universe
Not Available
1.5 * 10-3 %
7
Abundance In Sun
~-9999 %
~0.002 %
7
Abundance In Meteorites
Not Available
0.30 %
7
Abundance In Earth's Crust
0.00 %
99+
0.01 %
13
Abundance In Oceans
0.00 %
99+
0.00 %
16
Abundance In Humans
Not Available
0.00 %
16
Uses
Uses & Benefits
- Currently known uses of Protactinium metal are limited to research purpose only.
- 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.
Industrial Uses
NA
Automobile Industry, Chemical Industry
Medical Uses
NA
NA
Other Uses
NA
Alloys
Biological Properties
Toxicity
Highly Toxic
Highly Toxic
Present in Human Body
No
Yes
In Blood
0.00 Blood/mg dm-3
37
0.11 Blood/mg dm-3
12
In Bone
0.00 p.p.m.
36
0.33 p.p.m.
21
Physical Properties
Melting Point
1,568.00 °C
21
1,857.00 °C
14
Boiling Point
4,027.00 °C
12
2,672.00 °C
39
Appearance
Physical State
Solid
Solid
Color
Silver
Silver
Luster
Metallic
Metallic
Hardness
Mohs Hardness
Not Available
8.50
1
Brinell Hardness
Not Available
687.00 MPa
16
Vickers Hardness
Not Available
1,060.00 MPa
10
Speed of Sound
Not Available
5,940.00 m/s
5
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
Pa
Cr
Isotopes
Known Isotopes
27
12
21
18
Electronegativity
Pauling Electronegativity
1.50
27
1.66
18
Sanderson Electronegativity
Not Available
1.66
14
Allred Rochow Electronegativity
1.14
28
1.56
10
Allen Electronegativity
Not Available
1.65
19
Electropositivity
Pauling Electropositivity
2.50
27
2.34
36
Ionization Energies
1st Energy Level
568.00 kJ/mol
99+
26,130.00 kJ/mol
1
2nd Energy Level
1,128.00 kJ/mol
99+
28,750.00 kJ/mol
1
3rd Energy Level
1,814.00 kJ/mol
99+
34,230.00 kJ/mol
1
4th Energy Level
2,991.00 kJ/mol
99+
37,066.00 kJ/mol
1
5th Energy Level
Not Available
97,510.00 kJ/mol
1
6th Energy Level
Not Available
105,800.00 kJ/mol
1
7th Energy level
Not Available
114,300.00 kJ/mol
1
8th Energy Level
Not Available
125,300.00 kJ/mol
1
9th Energy Level
Not Available
134,700.00 kJ/mol
1
10th Energy Level
Not Available
144,300.00 kJ/mol
1
11th Energy Level
Not Available
26,130.00 kJ/mol
12
12th Energy Level
Not Available
28,750.00 kJ/mol
13
13th Energy Level
Not Available
34,230.00 kJ/mol
10
14th Energy Level
Not Available
37,066.00 kJ/mol
12
15th Energy Level
Not Available
97,510.00 kJ/mol
1
16th Energy Level
Not Available
105,800.00 kJ/mol
2
17th Energy Level
Not Available
114,300.00 kJ/mol
3
18th Energy Level
Not Available
125,300.00 kJ/mol
4
19th Energy Level
Not Available
134,700.00 kJ/mol
5
20th Energy Level
Not Available
144,300.00 kJ/mol
7
21st Energy Level
Not Available
157,700.00 kJ/mol
7
22nd Energy Level
Not Available
166,090.00 kJ/mol
6
Electrochemical Equivalent
1.72 g/amp-hr
99+
0.32 g/amp-hr
99+
Electron Work Function
Not Available
4.50 eV
14
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
91
27
24
99+
Electron Configuration
[Rn] 5f2 6d1 7s2
[Ar] 3d5 4s1
Crystal Structure
Tetragonal (TETR)
Body Centered Cubic (BCC)
Crystal Lattice
TETR-Crystal-Structure-of-Protactinium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
91
27
24
99+
Number of Neutrons
122
21
28
99+
Number of Electrons
91
27
24
99+
Radius of an Atom
Atomic Radius
163.00 pm
25
128.00 pm
99+
Covalent Radius
200.00 pm
11
139.00 pm
99+
Van der Waals Radius
243.00 pm
11
200.00 pm
28
Atomic Weight
231.04 amu
24
52.00 amu
99+
Atomic Volume
15.00 cm3/mol
34
7.23 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
92.00 (-eV)
11
170.00 (-eV)
4
Lattice Constant
392.50 pm
23
291.00 pm
99+
Lattice Angles
π/2, π/2, π/2
π/2, π/2, π/2
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
15.37 g/cm3
20
7.19 g/cm3
99+
Density When Liquid (at m.p.)
Not Available
6.30 g/cm3
40
Tensile Strength
Not Available
689.00 MPa
7
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
0.00 (Pa)
24
Vapor Pressure at 2000 K
Not Available
774.00 (Pa)
1
Elasticity properties
Shear Modulus
Not Available
115.00 GPa
9
Bulk Modulus
Not Available
160.00 GPa
11
Young's Modulus
Not Available
279.00 GPa
8
Poisson Ratio
Not Available
0.21
32
Other Mechanical Properties
Unknown
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
15.37
12
7.19
99+
Magnetic Ordering
Paramagnetic
Antiferromagnetic
Electrical Properties
Electrical Property
Conductor
NA
Resistivity
177.00 nΩ·m
21
125.00 nΩ·m
27
Electrical Conductivity
0.05 106/cm Ω
34
0.08 106/cm Ω
25
Electron Affinity
Not Available
64.30 kJ/mol
15
Thermal Properties
Specific Heat
0.12 J/(kg K)
40
0.45 J/(kg K)
12
Molar Heat Capacity
Not Available
23.35 J/mol·K
99+
Thermal Conductivity
47.00 W/m·K
32
93.90 W/m·K
17
Critical Temperature
Not Available
Not Available
Thermal Expansion
9.90 µm/(m·K)
40
4.90 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
Not Available
348.80 kJ/mol
24
Enthalpy of Fusion
12.34 kJ/mol
28
15.31 kJ/mol
20
Enthalpy of Atomization
Not Available
397.50 kJ/mol
21
Standard Molar Entropy
198.10 J/mol.K
1
23.80 J/mol.K
99+
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