Symbol
Rh
  
Mo
  
Period Number
5
  
5
  
Block
d block
  
d block
  
Element Family
Transition Metal
  
Transition Metal
  
Space Group Name
Fm_ 3m
  
Im_ 3m
  
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.
  
- Molybdenum is highly reactive metal, hence not found free in nature .
- Till 18th century Molybdenum element were often mistaken as a carbon or Lead.
  
Sources
Earth's crust, Found As a By-product, Found in Minerals, Mining
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
William Hyde Wollaston
  
Carl Wilhelm Scheele
  
Discovery
In 1804
  
In 1778
  
Abundance
  
  
Abundance In Sun
~0.0000002 %
  
25
~0.0000009 %
  
19
Abundance In Earth's Crust
Abundance In Oceans
Not Available
  
Abundance In Humans
Not Available
  
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.
  
- Its alloys are used to make engine parts, drills, saw blade, etc.
- Lubricant additive made up of Molybdenum disulfide is commonly used in the industry. It is also used as a catalyst.
  
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
  
Aerospace Industry, Electrical Industry, Electronic Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
NA
  
Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
Not Available
  
0.00 Blood/mg dm-3
  
31
In Bone
Not Available
  
0.70 p.p.m.
  
18
Melting Point
1,966.00 °C
  
12
Boiling Point
3,727.00 °C
  
17
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery White
  
Gray
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Brinell Hardness
1,370.00 MPa
  
7
Vickers Hardness
1,100.00 MPa
  
9
1,400.00 MPa
  
6
Speed of Sound
4,700.00 m/s
  
15
5,400.00 m/s
  
6
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Rh
  
Mo
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
719.70 kJ/mol
  
29
684.30 kJ/mol
  
37
2nd Energy Level
1,740.00 kJ/mol
  
26
1,560.00 kJ/mol
  
37
3rd Energy Level
2,997.00 kJ/mol
  
27
2,618.00 kJ/mol
  
99+
4th Energy Level
Not Available
  
4,480.00 kJ/mol
  
26
5th Energy Level
Not Available
  
5,257.00 kJ/mol
  
32
6th Energy Level
Not Available
  
6,640.80 kJ/mol
  
22
7th Energy level
Not Available
  
12,125.00 kJ/mol
  
13
8th Energy Level
Not Available
  
13,860.00 kJ/mol
  
16
9th Energy Level
Not Available
  
15,835.00 kJ/mol
  
16
10th Energy Level
Not Available
  
17,980.00 kJ/mol
  
18
11th Energy Level
Not Available
  
20,190.00 kJ/mol
  
17
12th Energy Level
Not Available
  
22,219.00 kJ/mol
  
15
13th Energy Level
Not Available
  
26,930.00 kJ/mol
  
13
14th Energy Level
Not Available
  
29,196.00 kJ/mol
  
13
15th Energy Level
Not Available
  
52,490.00 kJ/mol
  
7
16th Energy Level
Not Available
  
55,000.00 kJ/mol
  
8
17th Energy Level
Not Available
  
61,400.00 kJ/mol
  
9
18th Energy Level
Not Available
  
67,700.00 kJ/mol
  
9
19th Energy Level
Not Available
  
74,000.00 kJ/mol
  
9
20th Energy Level
Not Available
  
80,400.00 kJ/mol
  
10
21st Energy Level
Not Available
  
87,000.00 kJ/mol
  
9
22nd Energy Level
Not Available
  
93,400.00 kJ/mol
  
7
23rd Energy Level
Not Available
  
98,420.00 kJ/mol
  
6
24th Energy Level
Not Available
  
104,400.00 kJ/mol
  
2
25th Energy Level
Not Available
  
121,900.00 kJ/mol
  
1
26th Energy Level
Not Available
  
127,700.00 kJ/mol
  
1
27th Energy Level
Not Available
  
133,800.00 kJ/mol
  
1
28th Energy Level
Not Available
  
139,800.00 kJ/mol
  
1
29th Energy Level
Not Available
  
148,100.00 kJ/mol
  
1
30th Energy Level
Not Available
  
154,500.00 kJ/mol
  
1
Electrochemical Equivalent
1.28 g/amp-hr
  
99+
0.89 g/amp-hr
  
99+
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
  
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Kr] 4d8 5s1
  
[Kr] 4d5 5s1
  
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
  
  
Radius of an Atom
  
  
Atomic Weight
102.91 amu
  
99+
Atomic Volume
8.30 cm3/mol
  
99+
9.40 cm3/mol
  
99+
Adjacent Atomic Numbers
  
  
Valence Electron Potential
64.00 (-eV)
  
22
88.60 (-eV)
  
13
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
12.41 g/cm3
  
28
10.28 g/cm3
  
36
Density When Liquid (at m.p.)
10.70 g/cm3
  
14
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Other Mechanical Properties
Malleable
  
Ductile, Weldable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Semiconductor
  
Resistivity
43.30 nΩ·m
  
99+
53.40 nΩ·m
  
99+
Electrical Conductivity
0.21 106/cm Ω
  
8
0.19 106/cm Ω
  
11
Electron Affinity
109.70 kJ/mol
  
7
71.90 kJ/mol
  
14
Specific Heat
0.24 J/(kg K)
  
22
0.25 J/(kg K)
  
21
Molar Heat Capacity
24.98 J/mol·K
  
99+
24.06 J/mol·K
  
99+
Thermal Conductivity
150.00 W/m·K
  
9
138.00 W/m·K
  
12
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
8.20 µm/(m·K)
  
99+
4.80 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
495.40 kJ/mol
  
12
594.10 kJ/mol
  
8
Enthalpy of Fusion
21.76 kJ/mol
  
10
27.61 kJ/mol
  
5
Enthalpy of Atomization
556.50 kJ/mol
  
12
653.00 kJ/mol
  
7
Standard Molar Entropy
31.50 J/mol.K
  
99+
28.70 J/mol.K
  
99+