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Rhodium Holmium Comparison


Holmium Rhodium comparison


Periodic Table

Symbol
Rh   
Ho   

Group Number
9   
9
Not Available   

Period Number
5   
6   

Block
d block   
f block   

Element Family
Transition Metal   
Lanthanide   

CAS Number
7440166   
99+
7440600   
29

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.
  
  • Holmium metal is very soft and malleable.
  • Holmium metal is well known for its corrosion resistivity.
  

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   
Marc Delafontaine   

Discovery
In 1804   
In 1878   

Abundance
  
  

Abundance In Universe
6 * 10-8 %   
26
5 * 10-8 %   
27

Abundance In Sun
~0.0000002 %   
25
~-9999 %   

Abundance In Meteorites
0.00 %   
36
0.00 %   
99+

Abundance In Earth's Crust
0.00 %   
99+
0.00 %   
38

Abundance In Oceans
Not Available   
0.00 %   
99+

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.
  
  • Holmium metal has an ability to absorb neutrons, so this metal is used in nuclear reactors to keep the chain reactions of elements under control.
  • Alloys of Holmium are used to produce Magnet.
  

Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry   
NA   

Medical Uses
NA   
NA   

Other Uses
Alloys   
Alloys, Nuclear Research   

Biological Properties
  
  

Toxicity
NA   
Low Toxic   

Present in Human Body
No   
No   

Physical Properties

Melting Point
1,966.00 °C   
12
1,461.00 °C   
30

Boiling Point
3,727.00 °C   
17
2,600.00 °C   
99+

Appearance
  
  

Physical State
Solid   
Solid   

Color
Silvery White   
Silvery White   

Luster
Metallic   
Metallic   

Hardness
  
  

Mohs Hardness
6.00   
6
Not Available   

Brinell Hardness
980.00 MPa   
9
746.00 MPa   
13

Vickers Hardness
1,100.00 MPa   
9
481.00 MPa   
23

Speed of Sound
4,700.00 m/s   
15
2,760.00 m/s   
30

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   
Ho   

Isotopes
  
  

Known Isotopes
16   
23
34   
5

Electronegativity
  
  

Pauling Electronegativity
2.28   
3
1.23   
37

Allred Rochow Electronegativity
1.45   
16
1.10   
30

Allen Electronegativity
1.56   
24
Not Available   

Electropositivity
  
  

Pauling Electropositivity
1.72   
99+
2.77   
17

Ionization Energies
  
  

1st Energy Level
719.70 kJ/mol   
29
581.00 kJ/mol   
99+

2nd Energy Level
1,740.00 kJ/mol   
26
1,140.00 kJ/mol   
99+

3rd Energy Level
2,997.00 kJ/mol   
27
2,204.00 kJ/mol   
99+

4th Energy Level
Not Available   
4,100.00 kJ/mol   
34

Electrochemical Equivalent
1.28 g/amp-hr   
99+
2.02 g/amp-hr   
29

Electron Work Function
4.98 eV   
6
Not Available   

Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes   
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility   

Atomic Properties

Atomic Number
45   
99+
67   
99+

Electron Configuration
[Kr] 4d8 5s1   
[Xe] 4f11 6s2   

Crystal Structure
Face Centered Cubic (FCC)   
Hexagonal Close Packed (HCP)   

Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100   
HCP-Crystal-Structure-of-Holmium.jpg#100   

Atom
  
  

Number of Protons
45   
99+
67   
99+

Number of Neutrons
58   
99+
98   
34

Number of Electrons
45   
99+
67   
99+

Radius of an Atom
  
  

Atomic Radius
134.00 pm   
99+
176.00 pm   
18

Covalent Radius
142.00 pm   
99+
192.00 pm   
17

Van der Waals Radius
200.00 pm   
28
216.00 pm   
24

Atomic Weight
102.91 amu   
99+
164.93 amu   
99+

Atomic Volume
8.30 cm3/mol   
99+
18.70 cm3/mol   
24

Adjacent Atomic Numbers
  
  

Previous Element
Ruthenium
  
Dysprosium
  

Next Element
Palladium
  
Erbium
  

Valence Electron Potential
64.00 (-eV)   
22
47.90 (-eV)   
31

Lattice Constant
380.34 pm   
27
357.73 pm   
38

Lattice Angles
π/2, π/2, π/2   
π/2, π/2, 2 π/3   

Lattice C/A Ratio
Not Available   
1.57   
17

Mechanical Properties

Density
  
  

Density At Room Temperature
12.41 g/cm3   
28
8.79 g/cm3   
99+

Density When Liquid (at m.p.)
10.70 g/cm3   
14
8.34 g/cm3   
26

Tensile Strength
951.00 MPa   
5
Not Available   

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Vapor Pressure at 1000 K
Not Available   
0.00 (Pa)   
16

Vapor Pressure at 2000 K
0.02 (Pa)   
19
Not Available   

Elasticity properties
  
  

Shear Modulus
150.00 GPa   
6
26.30 GPa   
28

Bulk Modulus
275.00 GPa   
5
40.20 GPa   
32

Young's Modulus
380.00 GPa   
5
64.80 GPa   
31

Poisson Ratio
0.26   
22
0.23   
29

Other Mechanical Properties
Malleable   
Ductile, Malleable, Sectile   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
12.41   
20
8.80   
35

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Conductor   
Conductor   

Resistivity
43.30 nΩ·m   
99+
814.00 nΩ·m   
4

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

Thermal Properties

Specific Heat
0.24 J/(kg K)   
22
0.16 J/(kg K)   
35

Molar Heat Capacity
24.98 J/mol·K   
99+
27.15 J/mol·K   
19

Thermal Conductivity
150.00 W/m·K   
9
16.20 W/m·K   
99+

Critical Temperature
Not Available   
Not Available   

Thermal Expansion
8.20 µm/(m·K)   
99+
11.20 µm/(m·K)   
35

Enthalpy
  
  

Enthalpy of Vaporization
495.40 kJ/mol   
12
241.00 kJ/mol   
38

Enthalpy of Fusion
21.76 kJ/mol   
10
11.76 kJ/mol   
29

Enthalpy of Atomization
556.50 kJ/mol   
12
301.00 kJ/mol   
36

Standard Molar Entropy
31.50 J/mol.K   
99+
75.30 J/mol.K   
8

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