Rhodium vs Thallium
Periodic Table
Symbol
Rh
Tl
Group Number
9
9
13
5
Period Number
5
6
Block
d block
p block
Element Family
Transition Metal
Post-Transition
CAS Number
7440166
99+
7440280
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.
- Compounds of Thallium metal are highly Toxic.
- Thallium metal is being suspected as a human carcinogen.
Sources
Earth's crust, Found As a By-product, Found in Minerals, Mining
Found As a By-product, Ores of metals, Ores of Minerals
History
Who Discovered
William Hyde Wollaston
William Crookes
Discovery
In 1804
In 1861
Abundance
Abundance In Universe
6 * 10-8 %
26
5 * 10-9 %
32
Abundance In Sun
~0.0000002 %
25
~0.0000001 %
26
Abundance In Meteorites
0.00 %
36
0.00 %
99+
Abundance In Earth's Crust
0.00 %
99+
0.00 %
99+
Abundance In Oceans
Not Available
0.00 %
34
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.
- Thallium is a toxic metal and hence it has limited uses. Thallium metal is mostly used for producing photoelectric cells.
- In thermometer’s mercury alloy has 8% of thallium, as it has a melting point lower than 20°C.
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Chemical Industry
Medical Uses
NA
Medical Research
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
NA
Highly Toxic
Present in Human Body
No
Yes
In Blood
Not Available
0.00 Blood/mg dm-3
34
In Bone
Not Available
0.00 p.p.m.
33
Physical Properties
Melting Point
1,966.00 °C
12
303.50 °C
99+
Boiling Point
3,727.00 °C
17
1,457.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silvery White
Luster
Metallic
NA
Hardness
Mohs Hardness
6.00
6
1.20
20
Brinell Hardness
980.00 MPa
9
26.50 MPa
99+
Vickers Hardness
1,100.00 MPa
9
Not Available
Speed of Sound
4,700.00 m/s
15
818.00 m/s
99+
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
Tl
Isotopes
Known Isotopes
16
23
32
7
Electronegativity
Pauling Electronegativity
2.28
3
1.62
21
Sanderson Electronegativity
Not Available
2.25
5
Allred Rochow Electronegativity
1.45
16
1.44
17
Mulliken-Jaffe Electronegativity
Not Available
1.96
6
Allen Electronegativity
1.56
24
1.79
13
Electropositivity
Pauling Electropositivity
1.72
99+
2.38
33
Ionization Energies
1st Energy Level
719.70 kJ/mol
29
589.40 kJ/mol
99+
2nd Energy Level
1,740.00 kJ/mol
26
1,971.00 kJ/mol
14
3rd Energy Level
2,997.00 kJ/mol
27
2,878.00 kJ/mol
32
Electrochemical Equivalent
1.28 g/amp-hr
99+
7.63 g/amp-hr
2
Electron Work Function
4.98 eV
6
3.84 eV
28
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
45
99+
81
35
Electron Configuration
[Kr] 4d8 5s1
[Xe] 4f14 5d10 6s2 6p1
Crystal Structure
Face Centered Cubic (FCC)
Hexagonal Close Packed (HCP)
Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
45
99+
81
35
Number of Neutrons
58
99+
123
20
Number of Electrons
45
99+
81
35
Radius of an Atom
Atomic Radius
134.00 pm
99+
170.00 pm
22
Covalent Radius
142.00 pm
99+
145.00 pm
39
Van der Waals Radius
200.00 pm
28
196.00 pm
30
Atomic Weight
102.91 amu
99+
204.38 amu
31
Atomic Volume
8.30 cm3/mol
99+
17.20 cm3/mol
31
Adjacent Atomic Numbers
Valence Electron Potential
64.00 (-eV)
22
9.60 (-eV)
99+
Lattice Constant
380.34 pm
27
345.66 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
6
Mechanical Properties
Density
Density At Room Temperature
12.41 g/cm3
28
11.85 g/cm3
31
Density When Liquid (at m.p.)
10.70 g/cm3
14
11.22 g/cm3
13
Tensile Strength
951.00 MPa
5
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
16.90 (Pa)
5
Vapor Pressure at 2000 K
0.02 (Pa)
19
Not Available
Elasticity properties
Shear Modulus
150.00 GPa
6
2.80 GPa
99+
Bulk Modulus
275.00 GPa
5
43.00 GPa
28
Young's Modulus
380.00 GPa
5
8.00 GPa
99+
Poisson Ratio
0.26
22
0.45
2
Other Mechanical Properties
Malleable
Ductile, Sectile
Magnetic Properties
Magnetic Characteristics
Specific Gravity
12.41
20
11.85
22
Magnetic Ordering
Paramagnetic
Diamagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
43.30 nΩ·m
99+
0.18 nΩ·m
99+
Electrical Conductivity
0.21 106/cm Ω
8
0.06 106/cm Ω
32
Electron Affinity
109.70 kJ/mol
7
19.20 kJ/mol
32
Thermal Properties
Specific Heat
0.24 J/(kg K)
22
0.13 J/(kg K)
39
Molar Heat Capacity
24.98 J/mol·K
99+
26.32 J/mol·K
29
Thermal Conductivity
150.00 W/m·K
9
46.10 W/m·K
33
Critical Temperature
Not Available
Not Available
Thermal Expansion
8.20 µm/(m·K)
99+
29.90 µm/(m·K)
12
Enthalpy
Enthalpy of Vaporization
495.40 kJ/mol
12
162.10 kJ/mol
99+
Enthalpy of Fusion
21.76 kJ/mol
10
4.27 kJ/mol
99+
Enthalpy of Atomization
556.50 kJ/mol
12
179.90 kJ/mol
99+
Standard Molar Entropy
31.50 J/mol.K
99+
64.20 J/mol.K
19
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