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Rhodium vs Osmium


Osmium vs Rhodium


Periodic Table

Symbol
Rh   
Os   

Group Number
9   
9
8   
10

Period Number
5   
6   

Block
d block   
d block   

Element Family
Transition Metal   
Transition Metal   

CAS Number
7440166   
99+
7440042   
99+

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.
  
  • Osmium metal does not oxidize in air unless it is heated.
  • But if it heated den it forms Osmium Tetroxide, which is highly toxic.
  

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

History
  
  

Who Discovered
William Hyde Wollaston   
Smithson Tennant   

Discovery
In 1804   
In 1803   

Abundance
  
  

Abundance In Universe
6 * 10-8 %   
26
3 * 10-7 %   
21

Abundance In Sun
~0.0000002 %   
25
~0.0000002 %   
25

Abundance In Meteorites
0.00 %   
36
0.00 %   
28

Abundance In Earth's Crust
0.00 %   
99+
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.
  
  • Its has very limited uses and its alloys are very hard and are used in the manufacturing of pen tips, pivots, needles and electrical contacts.
  • It is also used as industrial catalyst to speed up the chemical reaction.
  

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

Medical Uses
NA   
NA   

Other Uses
Alloys   
Alloys   

Biological Properties
  
  

Toxicity
NA   
Highly Toxic   

Present in Human Body
No   
No   

Physical Properties

Melting Point
1,966.00 °C   
12
3,045.00 °C   
3

Boiling Point
3,727.00 °C   
17
5,027.00 °C   
6

Appearance
  
  

Physical State
Solid   
Solid   

Color
Silvery White   
Silvery Bluish-Gray   

Luster
Metallic   
Metallic   

Hardness
  
  

Mohs Hardness
6.00   
6
7.00   
3

Brinell Hardness
980.00 MPa   
9
3,490.00 MPa   
1

Vickers Hardness
1,100.00 MPa   
9
Not Available   

Speed of Sound
4,700.00 m/s   
15
4,940.00 m/s   
11

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   
Os   

Isotopes
  
  

Known Isotopes
16   
23
35   
4

Electronegativity
  
  

Pauling Electronegativity
2.28   
3
2.20   
4

Allred Rochow Electronegativity
1.45   
16
1.52   
12

Allen Electronegativity
1.56   
24
1.65   
19

Electropositivity
  
  

Pauling Electropositivity
1.72   
99+
1.80   
99+

Ionization Energies
  
  

1st Energy Level
719.70 kJ/mol   
29
840.00 kJ/mol   
12

2nd Energy Level
1,740.00 kJ/mol   
26
1,309.80 kJ/mol   
99+

3rd Energy Level
2,997.00 kJ/mol   
27
1,600.00 kJ/mol   
99+

Electrochemical Equivalent
1.28 g/amp-hr   
99+
1.77 g/amp-hr   
38

Electron Work Function
4.98 eV   
6
4.83 eV   
8

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

Atomic Properties

Atomic Number
45   
99+
76   
40

Electron Configuration
[Kr] 4d8 5s1   
[Xe] 4f14 5d6 6s2   

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

Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100   
BCC-Crystal-Structure-.jpg#100   

Atom
  
  

Number of Protons
45   
99+
76   
39

Number of Neutrons
58   
99+
114   
25

Number of Electrons
45   
99+
76   
39

Radius of an Atom
  
  

Atomic Radius
134.00 pm   
99+
133.80 pm   
99+

Covalent Radius
142.00 pm   
99+
Not Available   

Van der Waals Radius
200.00 pm   
28
216.00 pm   
24

Atomic Weight
102.91 amu   
99+
190.23 amu   
35

Atomic Volume
8.30 cm3/mol   
99+
8.49 cm3/mol   
99+

Adjacent Atomic Numbers
  
  

Previous Element
Ruthenium
  
Rhenium
  

Next Element
Palladium
  
Iridium
  

Valence Electron Potential
64.00 (-eV)   
22
91.40 (-eV)   
12

Lattice Constant
380.34 pm   
27
273.44 pm   
99+

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

Lattice C/A Ratio
Not Available   
1.58   
14

Mechanical Properties

Density
  
  

Density At Room Temperature
12.41 g/cm3   
28
22.59 g/cm3   
9

Density When Liquid (at m.p.)
10.70 g/cm3   
14
20.00 g/cm3   
1

Tensile Strength
951.00 MPa   
5
1,000.00 MPa   
4

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

Vapor Pressure at 2000 K
0.02 (Pa)   
19
0.00 (Pa)   
28

Elasticity properties
  
  

Shear Modulus
150.00 GPa   
6
222.00 GPa   
1

Bulk Modulus
275.00 GPa   
5
462.00 GPa   
1

Young's Modulus
380.00 GPa   
5
Not Available   

Poisson Ratio
0.26   
22
0.25   
24

Other Mechanical Properties
Malleable   
Ductile   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
12.41   
20
22.57   
2

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Conductor   
Conductor   

Resistivity
43.30 nΩ·m   
99+
81.20 nΩ·m   
35

Electrical Conductivity
0.21 106/cm Ω   
8
0.11 106/cm Ω   
18

Electron Affinity
109.70 kJ/mol   
7
106.10 kJ/mol   
9

Thermal Properties

Specific Heat
0.24 J/(kg K)   
22
0.13 J/(kg K)   
39

Molar Heat Capacity
24.98 J/mol·K   
99+
24.70 J/mol·K   
99+

Thermal Conductivity
150.00 W/m·K   
9
87.60 W/m·K   
19

Critical Temperature
Not Available   
Not Available   

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

Enthalpy
  
  

Enthalpy of Vaporization
495.40 kJ/mol   
12
627.60 kJ/mol   
7

Enthalpy of Fusion
21.76 kJ/mol   
10
29.30 kJ/mol   
4

Enthalpy of Atomization
556.50 kJ/mol   
12
669.00 kJ/mol   
6

Standard Molar Entropy
31.50 J/mol.K   
99+
32.60 J/mol.K   
99+

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