Rhodium vs Technetium
Periodic Table
Symbol
Rh
Tc
Group Number
9
9
7
11
Period Number
5
5
Block
d block
d block
Element Family
Transition Metal
Transition Metal
CAS Number
7440166
99+
7440268
99+
Space Group Name
Fm_ 3m
P63/mmc
Space Group Number
225.00
2
194.00
5
Facts
Interesting Facts
- Rhodium is the rarest element out of all non-radioactive metals on the earth .
- Rhodium is one of the most durable and hard metal, which also have high reflectance.
- Original name of Technetium was Masurium.
- At the time of its discovery it found in sample of Molybdenum.
Sources
Earth's crust, Found As a By-product, Found in Minerals, Mining
Made by Bombarding Molybdenum with Deuterons
History
Who Discovered
William Hyde Wollaston
Emilio Segrè and Carlo Perriero
Discovery
In 1804
In 1937
Abundance
Abundance In Universe
6 * 10-8 %
26
Not Available
Abundance In Sun
~0.0000002 %
25
~-9999 %
Abundance In Meteorites
0.00 %
36
Not Available
Abundance In Earth's Crust
0.00 %
99+
Not Available
Uses
Uses & Benefits
- Rhodium metal is mainly used in catalytic converters for cars as it reduces nitrogen oxides in exhaust gases.
- It is used as an industrial catalyst for nitric acid, acetic acid, hydrogenation reaction, etc.
- Technetium is a radioactive metal and hence it is used for medical studies and other research purposes.
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
NA
Medical Uses
NA
NA
Other Uses
Alloys
Alloys, Nuclear Research, Research Purposes
Biological Properties
Toxicity
NA
Low Toxic
Present in Human Body
No
No
In Blood
Not Available
0.00 Blood/mg dm-3
37
In Bone
Not Available
0.00 p.p.m.
36
Physical Properties
Melting Point
1,966.00 °C
12
2,200.00 °C
9
Boiling Point
3,727.00 °C
17
4,877.00 °C
7
Appearance
Physical State
Solid
Solid
Color
Silvery White
Shiny Gray
Luster
Metallic
NA
Hardness
Mohs Hardness
6.00
6
Not Available
Brinell Hardness
980.00 MPa
9
Not Available
Vickers Hardness
1,100.00 MPa
9
Not Available
Speed of Sound
4,700.00 m/s
15
16,200.00 m/s
1
Optical Properties
Reflectivity
84.00 %
4
Not Available
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
Rh
Tc
Isotopes
Known Isotopes
16
23
18
21
Electronegativity
Pauling Electronegativity
2.28
3
1.90
11
Allred Rochow Electronegativity
1.45
16
1.36
20
Allen Electronegativity
1.56
24
1.51
28
Electropositivity
Pauling Electropositivity
1.72
99+
2.10
99+
Ionization Energies
1st Energy Level
719.70 kJ/mol
29
702.00 kJ/mol
36
2nd Energy Level
1,740.00 kJ/mol
26
1,470.00 kJ/mol
99+
3rd Energy Level
2,997.00 kJ/mol
27
2,850.00 kJ/mol
33
Electrochemical Equivalent
1.28 g/amp-hr
99+
0.52 g/amp-hr
99+
Electron Work Function
4.98 eV
6
Not Available
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
Anti Corrosion, Ionization, Radioactive Isotopes, Radioactivity, Solubility
Atomic Properties
Atomic Number
45
99+
43
99+
Electron Configuration
[Kr] 4d8 5s1
[Kr] 4d5 5s2
Crystal Structure
Face Centered Cubic (FCC)
Hexagonal Close Packed (HCP)
Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100
HCP-Crystal-Structure-of-Technetium.jpg#100
Atom
Number of Protons
45
99+
43
99+
Number of Neutrons
58
99+
55
99+
Number of Electrons
45
99+
43
99+
Radius of an Atom
Atomic Radius
134.00 pm
99+
136.00 pm
99+
Covalent Radius
142.00 pm
99+
147.00 pm
37
Van der Waals Radius
200.00 pm
28
200.00 pm
28
Atomic Weight
102.91 amu
99+
98.00 amu
99+
Atomic Volume
8.30 cm3/mol
99+
8.50 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
64.00 (-eV)
22
180.00 (-eV)
3
Lattice Constant
380.34 pm
27
273.50 pm
99+
Lattice Angles
π/2, π/2, π/2
π/2, π/2, 2 π/3
Lattice C/A Ratio
Not Available
1.60
5
Mechanical Properties
Density
Density At Room Temperature
12.41 g/cm3
28
11.00 g/cm3
34
Density When Liquid (at m.p.)
10.70 g/cm3
14
Not Available
Tensile Strength
951.00 MPa
5
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 2000 K
0.02 (Pa)
19
Not Available
Elasticity properties
Shear Modulus
150.00 GPa
6
Not Available
Bulk Modulus
275.00 GPa
5
Not Available
Young's Modulus
380.00 GPa
5
Not Available
Poisson Ratio
0.26
22
Not Available
Other Mechanical Properties
Malleable
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
12.41
20
11.50
24
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
43.30 nΩ·m
99+
200.00 nΩ·m
18
Electrical Conductivity
0.21 106/cm Ω
8
0.07 106/cm Ω
30
Electron Affinity
109.70 kJ/mol
7
53.00 kJ/mol
18
Thermal Properties
Specific Heat
0.24 J/(kg K)
22
0.21 J/(kg K)
29
Molar Heat Capacity
24.98 J/mol·K
99+
24.27 J/mol·K
99+
Thermal Conductivity
150.00 W/m·K
9
50.60 W/m·K
30
Critical Temperature
Not Available
Not Available
Thermal Expansion
8.20 µm/(m·K)
99+
7.10 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
495.40 kJ/mol
12
660.00 kJ/mol
6
Enthalpy of Fusion
21.76 kJ/mol
10
23.01 kJ/mol
9
Enthalpy of Atomization
556.50 kJ/mol
12
649.00 kJ/mol
8
Standard Molar Entropy
31.50 J/mol.K
99+
181.10 J/mol.K
2
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