Symbol
Os
  
Cr
  
Period Number
6
  
4
  
Block
d block
  
d block
  
Element Family
Transition Metal
  
Transition Metal
  
Space Group Name
P63/mmc
  
Im_ 3m
  
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.
  
- Chromium is highly reactive, hence it is not found free in nature.
- Ores of Chromites mineral are the major source of Chromium metal.
- Almost 90% leather tanning is done with the help of chromium.
  
Sources
Found As a By-product, Found in Minerals, Mining
  
Found in Minerals, Mining, Ores of metals, Ores of Minerals
  
History
  
  
Who Discovered
Smithson Tennant
  
Louis Nicolas Vauquelin
  
Discovery
In 1803
  
In Between 1797 - 1798
  
Abundance
  
  
Abundance In Universe
1.5 * 10-3 %
  
7
Abundance In Sun
~0.0000002 %
  
25
Abundance In Earth's Crust
Abundance In Oceans
Not Available
  
Abundance In Humans
Not Available
  
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.
  
- It is used to harden the steel and produces a stainless steel and other various alloys.
- It is also used to give proper finish to polished mirrors. Its chromium plates are used in bathroom fittings.
  
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
  
Automobile Industry, Chemical Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Highly Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
Not Available
  
0.11 Blood/mg dm-3
  
12
In Bone
Not Available
  
0.33 p.p.m.
  
21
Melting Point
1,857.00 °C
  
14
Boiling Point
2,672.00 °C
  
39
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery Bluish-Gray
  
Silver
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Brinell Hardness
3,490.00 MPa
  
1
Vickers Hardness
Not Available
  
1,060.00 MPa
  
10
Speed of Sound
4,940.00 m/s
  
11
5,940.00 m/s
  
5
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Os
  
Cr
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
840.00 kJ/mol
  
12
26,130.00 kJ/mol
  
1
2nd Energy Level
1,309.80 kJ/mol
  
99+
28,750.00 kJ/mol
  
1
3rd Energy Level
1,600.00 kJ/mol
  
99+
34,230.00 kJ/mol
  
1
4th Energy Level
Not Available
  
37,066.00 kJ/mol
  
1
5th Energy Level
Not Available
  
97,510.00 kJ/mol
  
1
6th Energy Level
Not Available
  
105,800.00 kJ/mol
  
1
7th Energy level
Not Available
  
114,300.00 kJ/mol
  
1
8th Energy Level
Not Available
  
125,300.00 kJ/mol
  
1
9th Energy Level
Not Available
  
134,700.00 kJ/mol
  
1
10th Energy Level
Not Available
  
144,300.00 kJ/mol
  
1
11th Energy Level
Not Available
  
26,130.00 kJ/mol
  
12
12th Energy Level
Not Available
  
28,750.00 kJ/mol
  
13
13th Energy Level
Not Available
  
34,230.00 kJ/mol
  
10
14th Energy Level
Not Available
  
37,066.00 kJ/mol
  
12
15th Energy Level
Not Available
  
97,510.00 kJ/mol
  
1
16th Energy Level
Not Available
  
105,800.00 kJ/mol
  
2
17th Energy Level
Not Available
  
114,300.00 kJ/mol
  
3
18th Energy Level
Not Available
  
125,300.00 kJ/mol
  
4
19th Energy Level
Not Available
  
134,700.00 kJ/mol
  
5
20th Energy Level
Not Available
  
144,300.00 kJ/mol
  
7
21st Energy Level
Not Available
  
157,700.00 kJ/mol
  
7
22nd Energy Level
Not Available
  
166,090.00 kJ/mol
  
6
Electrochemical Equivalent
1.77 g/amp-hr
  
38
0.32 g/amp-hr
  
99+
Other Chemical Properties
Chemical Stability, Ionization, Solubility
  
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Xe] 4f14 5d6 6s2
  
[Ar] 3d5 4s1
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Body Centered Cubic (BCC)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Covalent Radius
Not Available
  
Atomic Volume
8.49 cm3/mol
  
99+
7.23 cm3/mol
  
99+
Adjacent Atomic Numbers
  
  
Valence Electron Potential
91.40 (-eV)
  
12
170.00 (-eV)
  
4
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
7.19 g/cm3
  
99+
Density When Liquid (at m.p.)
Tensile Strength
1,000.00 MPa
  
4
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Young's Modulus
Not Available
  
Other Mechanical Properties
Ductile
  
NA
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Antiferromagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
NA
  
Resistivity
125.00 nΩ·m
  
27
Electrical Conductivity
0.11 106/cm Ω
  
18
0.08 106/cm Ω
  
25
Electron Affinity
106.10 kJ/mol
  
9
64.30 kJ/mol
  
15
Specific Heat
0.13 J/(kg K)
  
39
0.45 J/(kg K)
  
12
Molar Heat Capacity
24.70 J/mol·K
  
99+
23.35 J/mol·K
  
99+
Thermal Conductivity
87.60 W/m·K
  
19
93.90 W/m·K
  
17
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
5.10 µm/(m·K)
  
99+
4.90 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
627.60 kJ/mol
  
7
348.80 kJ/mol
  
24
Enthalpy of Fusion
29.30 kJ/mol
  
4
15.31 kJ/mol
  
20
Enthalpy of Atomization
669.00 kJ/mol
  
6
397.50 kJ/mol
  
21
Standard Molar Entropy
32.60 J/mol.K
  
99+
23.80 J/mol.K
  
99+