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Osmium Rhodium Comparison


Rhodium Osmium comparison


Periodic Table

Symbol
Os   
Rh   

Group Number
8   
10
9   
9

Period Number
6   
5   

Block
d block   
d block   

Element Family
Transition Metal   
Transition Metal   

CAS Number
7440042   
99+
7440166   
99+

Space Group Name
P63/mmc   
Fm_ 3m   

Space Group Number
194.00   
5
225.00   
2

Facts

Interesting Facts
  • Osmium metal does not oxidize in air unless it is heated.
  • But if it heated den it forms Osmium Tetroxide, which is highly toxic.
  
  • 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 As a By-product, Found in Minerals, Mining   
Earth's crust, Found As a By-product, Found in Minerals, Mining   

History
  
  

Who Discovered
Smithson Tennant   
William Hyde Wollaston   

Discovery
In 1803   
In 1804   

Abundance
  
  

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

Abundance In Sun
~0.0000002 %   
25
~0.0000002 %   
25

Abundance In Meteorites
0.00 %   
28
0.00 %   
36

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

Uses

Uses & Benefits
  • 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.
  
  • 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
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
Highly Toxic   
NA   

Present in Human Body
No   
No   

Physical Properties

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

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

Appearance
  
  

Physical State
Solid   
Solid   

Color
Silvery Bluish-Gray   
Silvery White   

Luster
Metallic   
Metallic   

Hardness
  
  

Mohs Hardness
7.00   
3
6.00   
6

Brinell Hardness
3,490.00 MPa   
1
980.00 MPa   
9

Vickers Hardness
Not Available   
1,100.00 MPa   
9

Speed of Sound
4,940.00 m/s   
11
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
Os   
Rh   

Isotopes
  
  

Known Isotopes
35   
4
16   
23

Electronegativity
  
  

Pauling Electronegativity
2.20   
4
2.28   
3

Allred Rochow Electronegativity
1.52   
12
1.45   
16

Allen Electronegativity
1.65   
19
1.56   
24

Electropositivity
  
  

Pauling Electropositivity
1.80   
99+
1.72   
99+

Ionization Energies
  
  

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

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

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

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

Electron Work Function
4.83 eV   
8
4.98 eV   
6

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

Atomic Properties

Atomic Number
76   
40
45   
99+

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

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

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

Atom
  
  

Number of Protons
76   
39
45   
99+

Number of Neutrons
114   
25
58   
99+

Number of Electrons
76   
39
45   
99+

Radius of an Atom
  
  

Atomic Radius
133.80 pm   
99+
134.00 pm   
99+

Covalent Radius
Not Available   
142.00 pm   
99+

Van der Waals Radius
216.00 pm   
24
200.00 pm   
28

Atomic Weight
190.23 amu   
35
102.91 amu   
99+

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

Adjacent Atomic Numbers
  
  

Previous Element
Rhenium
  
Ruthenium
  

Next Element
Iridium
  
Palladium
  

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

Lattice Constant
273.44 pm   
99+
380.34 pm   
27

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

Lattice C/A Ratio
1.58   
14
Not Available   

Mechanical Properties

Density
  
  

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

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

Tensile Strength
1,000.00 MPa   
4
951.00 MPa   
5

Viscosity
Not Available   
Not Available   

Vapor Pressure
  
  

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

Elasticity properties
  
  

Shear Modulus
222.00 GPa   
1
150.00 GPa   
6

Bulk Modulus
462.00 GPa   
1
275.00 GPa   
5

Young's Modulus
Not Available   
380.00 GPa   
5

Poisson Ratio
0.25   
24
0.26   
22

Other Mechanical Properties
Ductile   
Malleable   

Magnetic Properties

Magnetic Characteristics
  
  

Specific Gravity
22.57   
2
12.41   
20

Magnetic Ordering
Paramagnetic   
Paramagnetic   

Electrical Properties
  
  

Electrical Property
Conductor   
Conductor   

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

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

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

Thermal Properties

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

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

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

Critical Temperature
Not Available   
Not Available   

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

Enthalpy
  
  

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

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

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

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

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