Symbol
Rh
  
Ce
  
Group Number
Not Available
  
Period Number
5
  
6
  
Block
d block
  
f block
  
Element Family
Transition Metal
  
Lanthanide
  
Space Group Name
Fm_ 3m
  
P63/mmc
  
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.
  
- Cerium is a rare earth metal but still it is not rare at all.
- It’s non-toxic compound Cerium sulfide has a rich red color and it is used as a pigment.
- Cerium metal is also used in Flat screen TVs, light bulb, floodlights, etc.
  
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
  
Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger
  
Discovery
In 1804
  
In 1803
  
Abundance
  
  
Abundance In Sun
~0.0000002 %
  
25
~0.0000004 %
  
23
Abundance In Earth's Crust
Abundance In Oceans
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.
  
- It is used to include flints for cigarette lighters.
- Its compound Cerium (Ill) Oxide is used as a catalyst; it is put inside the walls of the oven as it prevents from the buildup of cooking residues.
  
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
  
Moderately Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
Not Available
  
0.00 Blood/mg dm-3
  
30
In Bone
Not Available
  
2.70 p.p.m.
  
14
Melting Point
1,966.00 °C
  
12
Boiling Point
3,727.00 °C
  
17
3,257.00 °C
  
23
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery White
  
Silvery White
  
Luster
Metallic
  
Lustrous
  
Hardness
  
  
Brinell Hardness
186.00 MPa
  
99+
Vickers Hardness
1,100.00 MPa
  
9
Speed of Sound
4,700.00 m/s
  
15
2,100.00 m/s
  
99+
Optical Properties
  
  
Reflectivity
Not Available
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Rh
  
Ce
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
719.70 kJ/mol
  
29
534.40 kJ/mol
  
99+
2nd Energy Level
1,740.00 kJ/mol
  
26
1,050.00 kJ/mol
  
99+
3rd Energy Level
2,997.00 kJ/mol
  
27
1,949.00 kJ/mol
  
99+
4th Energy Level
Not Available
  
3,547.00 kJ/mol
  
99+
5th Energy Level
Not Available
  
6,325.00 kJ/mol
  
22
6th Energy Level
Not Available
  
7,490.00 kJ/mol
  
21
Electrochemical Equivalent
1.28 g/amp-hr
  
99+
1.74 g/amp-hr
  
99+
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
  
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Kr] 4d8 5s1
  
[Xe] 4f1 5d1 6s2
  
Crystal Structure
Face Centered Cubic (FCC)
  
Double Hexagonal Close Packed (DHCP)
  
Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100
  
DHCP-Crystal-Structure-of-Cerium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Weight
102.91 amu
  
99+
140.12 amu
  
99+
Atomic Volume
8.30 cm3/mol
  
99+
20.67 cm3/mol
  
17
Adjacent Atomic Numbers
  
  
Valence Electron Potential
64.00 (-eV)
  
22
41.78 (-eV)
  
99+
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
12.41 g/cm3
  
28
6.77 g/cm3
  
99+
Density When Liquid (at m.p.)
10.70 g/cm3
  
14
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Malleable
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
43.30 nΩ·m
  
99+
Electrical Conductivity
0.21 106/cm Ω
  
8
0.01 106/cm Ω
  
99+
Electron Affinity
109.70 kJ/mol
  
7
50.00 kJ/mol
  
21
Specific Heat
0.24 J/(kg K)
  
22
0.19 J/(kg K)
  
32
Molar Heat Capacity
24.98 J/mol·K
  
99+
26.94 J/mol·K
  
23
Thermal Conductivity
150.00 W/m·K
  
9
11.30 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
8.20 µm/(m·K)
  
99+
6.30 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
495.40 kJ/mol
  
12
414.00 kJ/mol
  
16
Enthalpy of Fusion
21.76 kJ/mol
  
10
5.46 kJ/mol
  
99+
Enthalpy of Atomization
556.50 kJ/mol
  
12
381.00 kJ/mol
  
23
Standard Molar Entropy
31.50 J/mol.K
  
99+
72.00 J/mol.K
  
12