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Holmium vs Rhodium


Rhodium vs Holmium


Periodic Table

Symbol
Ho   
Rh   

Group Number
Not Available   
9   
9

Period Number
6   
5   

Block
f block   
d block   

Element Family
Lanthanide   
Transition Metal   

CAS Number
7440600   
29
7440166   
99+

Space Group Name
P63/mmc   
Fm_ 3m   

Space Group Number
194.00   
5
225.00   
2

Facts

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

Sources
Found in Minerals, Mining, Ores of Minerals   
Earth's crust, Found As a By-product, Found in Minerals, Mining   

History
  
  

Who Discovered
Marc Delafontaine   
William Hyde Wollaston   

Discovery
In 1878   
In 1804   

Abundance
  
  

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

Abundance In Sun
~-9999 %   
~0.0000002 %   
25

Abundance In Meteorites
0.00 %   
99+
0.00 %   
36

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

Abundance In Oceans
0.00 %   
99+
Not Available   

Uses

Uses & Benefits
  • 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.
  
  • 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.
  

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

Medical Uses
NA   
NA   

Other Uses
Alloys, Nuclear Research   
Alloys   

Biological Properties
  
  

Toxicity
Low Toxic   
NA   

Present in Human Body
No   
No   

Physical Properties

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

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

Appearance
  
  

Physical State
Solid   
Solid   

Color
Silvery White   
Silvery White   

Luster
Metallic   
Metallic   

Hardness
  
  

Mohs Hardness
Not Available   
6.00   
6

Brinell Hardness
746.00 MPa   
13
980.00 MPa   
9

Vickers Hardness
481.00 MPa   
23
1,100.00 MPa   
9

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

Optical Properties
  
  

Reflectivity
Not Available   
84.00 %   
4

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
Ho   
Rh   

Isotopes
  
  

Known Isotopes
34   
5
16   
23

Electronegativity
  
  

Pauling Electronegativity
1.23   
37
2.28   
3

Allred Rochow Electronegativity
1.10   
30
1.45   
16

Allen Electronegativity
Not Available   
1.56   
24

Electropositivity
  
  

Pauling Electropositivity
2.77   
17
1.72   
99+

Ionization Energies
  
  

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

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

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

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

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

Electron Work Function
Not Available   
4.98 eV   
6

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

Atomic Properties

Atomic Number
67   
99+
45   
99+

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

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

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

Atom
  
  

Number of Protons
67   
99+
45   
99+

Number of Neutrons
98   
34
58   
99+

Number of Electrons
67   
99+
45   
99+

Radius of an Atom
  
  

Atomic Radius
176.00 pm   
18
134.00 pm   
99+

Covalent Radius
192.00 pm   
17
142.00 pm   
99+

Van der Waals Radius
216.00 pm   
24
200.00 pm   
28

Atomic Weight
164.93 amu   
99+
102.91 amu   
99+

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

Adjacent Atomic Numbers
  
  

Previous Element
Dysprosium
  
Ruthenium
  

Next Element
Erbium
  
Palladium
  

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

Lattice Constant
357.73 pm   
38
380.34 pm   
27

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

Lattice C/A Ratio
1.57   
17
Not Available   

Mechanical Properties

Density
  
  

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

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

Tensile Strength
Not Available   
951.00 MPa   
5

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

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

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

Elasticity properties
  
  

Shear Modulus
26.30 GPa   
28
150.00 GPa   
6

Bulk Modulus
40.20 GPa   
32
275.00 GPa   
5

Young's Modulus
64.80 GPa   
31
380.00 GPa   
5

Poisson Ratio
0.23   
29
0.26   
22

Other Mechanical Properties
Ductile, Malleable, Sectile   
Malleable   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
8.80   
35
12.41   
20

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Conductor   
Conductor   

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

Electrical Conductivity
0.01 106/cm Ω   
99+
0.21 106/cm Ω   
8

Electron Affinity
50.00 kJ/mol   
21
109.70 kJ/mol   
7

Thermal Properties

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

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

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

Critical Temperature
Not Available   
Not Available   

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

Enthalpy
  
  

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

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

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

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

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