Rhodium vs Potassium
Periodic Table
Symbol
Rh
K
Group Number
9
9
1
17
Period Number
5
4
Block
d block
s block
Element Family
Transition Metal
Alkali
CAS Number
7440166
99+
7440097
99+
Space Group Name
Fm_ 3m
Im_ 3m
Space Group Number
225.00
2
229.00
1
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.
- In the list of most abundant element Potassium is ranked 7th.
- Potassium can easily be sliced (chopped) down using knife.
Sources
Earth's crust, Found As a By-product, Found in Minerals, Mining
Found in Minerals, Mining
History
Who Discovered
William Hyde Wollaston
Humphry Davy
Discovery
In 1804
In 1807
Abundance
Abundance In Universe
6 * 10-8 %
26
3 * 10-4 %
9
Abundance In Sun
~0.0000002 %
25
~0.0004 %
9
Abundance In Meteorites
0.00 %
36
0.07 %
9
Abundance In Earth's Crust
0.00 %
99+
1.50 %
6
Abundance In Oceans
Not Available
0.04 %
3
Abundance In Humans
Not Available
0.20 %
2
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.
- Potassium’s compounds are in high demand for their application in Fertilizer manufacturing.
- Potassium carbonate is used in glass manufacturing and Potassium carbonate in manufacturing detergent and body wash.
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Ammunition Industry, Chemical Industry
Medical Uses
NA
Pharmaceutical Industry
Other Uses
Alloys
NA
Biological Properties
Toxicity
NA
Toxic
Present in Human Body
No
Yes
In Blood
Not Available
1,620.00 Blood/mg dm-3
2
In Bone
Not Available
2,100.00 p.p.m.
3
Physical Properties
Melting Point
1,966.00 °C
12
63.65 °C
99+
Boiling Point
3,727.00 °C
17
774.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silvery Gray
Luster
Metallic
NA
Hardness
Mohs Hardness
6.00
6
0.40
23
Brinell Hardness
980.00 MPa
9
0.36 MPa
99+
Vickers Hardness
1,100.00 MPa
9
Not Available
Speed of Sound
4,700.00 m/s
15
2,000.00 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
K
Isotopes
Known Isotopes
16
23
20
19
Electronegativity
Pauling Electronegativity
2.28
3
0.82
99+
Sanderson Electronegativity
Not Available
0.45
31
Allred Rochow Electronegativity
1.45
16
0.91
39
Mulliken-Jaffe Electronegativity
Not Available
0.73
23
Allen Electronegativity
1.56
24
0.73
99+
Electropositivity
Pauling Electropositivity
1.72
99+
3.18
3
Ionization Energies
1st Energy Level
719.70 kJ/mol
29
418.80 kJ/mol
99+
2nd Energy Level
1,740.00 kJ/mol
26
3,052.00 kJ/mol
5
3rd Energy Level
2,997.00 kJ/mol
27
4,420.00 kJ/mol
8
4th Energy Level
Not Available
5,877.00 kJ/mol
9
5th Energy Level
Not Available
7,975.00 kJ/mol
8
6th Energy Level
Not Available
9,590.00 kJ/mol
13
7th Energy level
Not Available
11,343.00 kJ/mol
17
8th Energy Level
Not Available
14,944.00 kJ/mol
13
9th Energy Level
Not Available
16,963.70 kJ/mol
15
10th Energy Level
Not Available
48,610.00 kJ/mol
3
11th Energy Level
Not Available
54,490.00 kJ/mol
4
12th Energy Level
Not Available
60,730.00 kJ/mol
4
13th Energy Level
Not Available
68,950.00 kJ/mol
4
14th Energy Level
Not Available
75,900.00 kJ/mol
5
15th Energy Level
Not Available
83,080.00 kJ/mol
6
16th Energy Level
Not Available
93,400.00 kJ/mol
7
17th Energy Level
Not Available
99,710.00 kJ/mol
8
Electrochemical Equivalent
1.28 g/amp-hr
99+
1.46 g/amp-hr
99+
Electron Work Function
4.98 eV
6
2.30 eV
99+
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
Chemical Stability, Flammability, Ionization, Solubility
Atomic Properties
Atomic Number
45
99+
19
99+
Electron Configuration
[Kr] 4d8 5s1
[Ar] 4s1
Crystal Structure
Face Centered Cubic (FCC)
Body Centered Cubic (BCC)
Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
45
99+
19
99+
Number of Neutrons
58
99+
20
99+
Number of Electrons
45
99+
19
99+
Radius of an Atom
Atomic Radius
134.00 pm
99+
227.00 pm
3
Covalent Radius
142.00 pm
99+
203.00 pm
9
Van der Waals Radius
200.00 pm
28
275.00 pm
5
Atomic Weight
102.91 amu
99+
39.10 amu
99+
Atomic Volume
8.30 cm3/mol
99+
45.46 cm3/mol
3
Adjacent Atomic Numbers
Valence Electron Potential
64.00 (-eV)
22
10.40 (-eV)
99+
Lattice Constant
380.34 pm
27
532.80 pm
12
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
12.41 g/cm3
28
0.86 g/cm3
99+
Density When Liquid (at m.p.)
10.70 g/cm3
14
0.83 g/cm3
99+
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
1.30 GPa
99+
Bulk Modulus
275.00 GPa
5
3.10 GPa
99+
Young's Modulus
380.00 GPa
5
3.53 GPa
99+
Poisson Ratio
0.26
22
Not Available
Other Mechanical Properties
Malleable
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
12.41
20
0.86
99+
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
43.30 nΩ·m
99+
72.00 nΩ·m
37
Electrical Conductivity
0.21 106/cm Ω
8
0.14 106/cm Ω
14
Electron Affinity
109.70 kJ/mol
7
48.40 kJ/mol
22
Thermal Properties
Specific Heat
0.24 J/(kg K)
22
0.75 J/(kg K)
6
Molar Heat Capacity
24.98 J/mol·K
99+
29.60 J/mol·K
6
Thermal Conductivity
150.00 W/m·K
9
102.50 W/m·K
15
Critical Temperature
Not Available
2,223.00 K
3
Thermal Expansion
8.20 µm/(m·K)
99+
83.30 µm/(m·K)
3
Enthalpy
Enthalpy of Vaporization
495.40 kJ/mol
12
77.50 kJ/mol
99+
Enthalpy of Fusion
21.76 kJ/mol
10
2.32 kJ/mol
99+
Enthalpy of Atomization
556.50 kJ/mol
12
89.50 kJ/mol
99+
Standard Molar Entropy
31.50 J/mol.K
99+
64.70 J/mol.K
18
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