Symbol
Hf
Cr
Group Number
46
0
17
👆🏻
Period Number
64
2
7
👆🏻
Block
d block
d block
Element Family
Transition Metal
Transition Metal
CAS Number
74405867440473
7429905
54386242
👆🏻
Space Group Name
P63/mmc
Im_ 3m
Space Group Number
194.00229.00
11
276
👆🏻
Interesting Facts
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
- 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
By-product Zirconium Refining
Found in Minerals, Mining, Ores of metals, Ores of Minerals
History
Who Discovered
Dirk Coster and George de Hevesy
Louis Nicolas Vauquelin
Discovery
In 1922
In Between 1797 - 1798
Abundance
Abundance In Universe
0.00 %0.00 %
0
0.11
👆🏻
Abundance In Sun
0.00 %0.00 %
0
0.1
👆🏻
Abundance In Meteorites
0.00 %0.30 %
0
22
👆🏻
Abundance In Earth's Crust
0.00 %0.01 %
1E-37
8.1
👆🏻
Abundance In Oceans
0.00 %0.00 %
0
1.1
👆🏻
Abundance In Humans
0.00 %0.00 %
0
1.4
👆🏻
Uses & Benefits
- It has an ability to absorb neutrons and hence it is used to make control rods in nuclear submarines. And this metal is also used in Plasma welding torches.
-
It alloys with iron, titanium and niobium are very useful.
- 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
Ammunition Industry
Automobile Industry, Chemical Industry
Medical Uses
-
-
Other Uses
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
Alloys
Biological Properties
Toxicity
Toxic
Highly Toxic
Present in Human Body
✔
✘
✔
✘
In Blood
0.00 Blood/mg dm-30.11 Blood/mg dm-3
0
1970
👆🏻
In Bone
0.00 p.p.m.0.33 p.p.m.
0
170000
👆🏻
Melting Point
2,150.00 °C1,857.00 °C
-38.83
3410
👆🏻
Boiling Point
5,400.00 °C2,672.00 °C
0
5660
👆🏻
Appearance
Physical State
Solid
Solid
Color
Gray
Silver
Luster
Metallic
Metallic
Hardness
Mohs Hardness
5.508.50
0.2
8.5
👆🏻
Brinell Hardness
1,450.00 MPa687.00 MPa
0.14
3490
👆🏻
Vickers Hardness
1,520.00 MPa1,060.00 MPa
0
3920
👆🏻
Speed of Sound
3,010.00 m/s5,940.00 m/s
818
16200
👆🏻
Optical Properties
Refractive Index
2.002.97
0.155
3.41
👆🏻
Reflectivity
71.00 %70.00 %
5
97
👆🏻
Allotropes
✔
✘
✔
✘
α Allotropes
-
-
β Allotropes
-
-
γ Allotropes
-
-
Chemical Formula
Hf
Cr
Isotopes
Known Isotopes
3221
0
38
👆🏻
Electronegativity
Pauling Electronegativity
1.301.66
0
2.6
👆🏻
Sanderson Electronegativity
1.301.66
0.22
2.56
👆🏻
Allred Rochow Electronegativity
1.231.56
0.86
1.9
👆🏻
Mulliken-Jaffe Electronegativity
1.301.66
0.62
2.48
👆🏻
Allen Electronegativity
1.161.65
0.659
2.7
👆🏻
Electropositivity
Pauling Electropositivity
2.702.34
1.46
3.3
👆🏻
Ionization Energies
1st Energy Level
658.50 kJ/mol26,130.00 kJ/mol
375.7
26130
👆🏻
2nd Energy Level
1,440.00 kJ/mol28,750.00 kJ/mol
392.8
28750
👆🏻
3rd Energy Level
2,250.00 kJ/mol34,230.00 kJ/mol
392.8
34230
👆🏻
4th Energy Level
3,216.00 kJ/mol37,066.00 kJ/mol
375.7
37066
👆🏻
5th Energy Level
6,585.00 kJ/mol97,510.00 kJ/mol
392
97510
👆🏻
6th Energy Level
6,585.00 kJ/mol105,800.00 kJ/mol
1007
105800
👆🏻
7th Energy level
6,580.00 kJ/mol114,300.00 kJ/mol
1007
114300
👆🏻
8th Energy Level
6,580.00 kJ/mol125,300.00 kJ/mol
730
125300
👆🏻
9th Energy Level
6,585.00 kJ/mol134,700.00 kJ/mol
1007
134700
👆🏻
10th Energy Level
6,590.00 kJ/mol144,300.00 kJ/mol
392
144300
👆🏻
11th Energy Level
6,585.00 kJ/mol26,130.00 kJ/mol
392
169988
👆🏻
12th Energy Level
6,580.00 kJ/mol28,750.00 kJ/mol
0
189368
👆🏻
13th Energy Level
6,580.00 kJ/mol34,230.00 kJ/mol
1007
76015
👆🏻
14th Energy Level
658.50 kJ/mol37,066.00 kJ/mol
380
86450
👆🏻
15th Energy Level
65,800.00 kJ/mol97,510.00 kJ/mol
33000
100700
👆🏻
16th Energy Level
658.50 kJ/mol105,800.00 kJ/mol
375.7
109480
👆🏻
17th Energy Level
658.50 kJ/mol114,300.00 kJ/mol
375.7
122200
👆🏻
18th Energy Level
6,585.00 kJ/mol125,300.00 kJ/mol
0
134810
👆🏻
19th Energy Level
658.50 kJ/mol134,700.00 kJ/mol
375.7
148700
👆🏻
20th Energy Level
658.00 kJ/mol144,300.00 kJ/mol
0
171200
👆🏻
21st Energy Level
658.50 kJ/mol157,700.00 kJ/mol
375.7
179100
👆🏻
22nd Energy Level
658.00 kJ/mol166,090.00 kJ/mol
330
184900
👆🏻
23rd Energy Level
658.50 kJ/mol653.80 kJ/mol
357.6
198800
👆🏻
24th Energy Level
658.50 kJ/mol653.80 kJ/mol
297.3
195200
👆🏻
25th Energy Level
658.00 kJ/mol653.80 kJ/mol
0
121900
👆🏻
26th Energy Level
658.50 kJ/mol653.80 kJ/mol
357.6
127700
👆🏻
27th Energy Level
658.50 kJ/mol652.90 kJ/mol
0
133800
👆🏻
28th Energy Level
658.50 kJ/mol653.80 kJ/mol
297.3
139800
👆🏻
29th Energy Level
658.50 kJ/mol653.80 kJ/mol
0
148100
👆🏻
30th Energy Level
658.00 kJ/mol653.80 kJ/mol
0
154500
👆🏻
Electrochemical Equivalent
1.66 g/amp-hr0.32 g/amp-hr
0.16812
8.3209
👆🏻
Electron Work Function
3.90 eV4.50 eV
2.14
6
👆🏻
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
Atomic Number
7224
3
117
👆🏻
Electron Configuration
[Xe] 4f14 5d2 6s2
[Ar] 3d5 4s1
Crystal Structure
Hexagonal Close Packed (HCP)
Body Centered Cubic (BCC)
Crystal Lattice
Atom
Number of Protons
7224
3
117
👆🏻
Number of Neutrons
10628
4
285
👆🏻
Number of Electrons
7224
3
117
👆🏻
Radius of an Atom
Atomic Radius
159.00 pm128.00 pm
0
348
👆🏻
Covalent Radius
175.00 pm139.00 pm
0
260
👆🏻
Van der Waals Radius
200.00 pm200.00 pm
0
348
👆🏻
Atomic Weight
178.49 amu52.00 amu
6.94
294
👆🏻
Atomic Volume
13.60 cm3/mol7.23 cm3/mol
1.39
71.07
👆🏻
Adjacent Atomic Numbers
Previous Element
Next Element
Valence Electron Potential
81.00 (-eV)170.00 (-eV)
0
392.42
👆🏻
Lattice Constant
319.64 pm291.00 pm
0
891.25
👆🏻
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.581.86
0.423
1.9
👆🏻
Density
Density At Room Temperature
13.31 g/cm37.19 g/cm3
0.534
40.7
👆🏻
Density When Liquid (at m.p.)
12.00 g/cm36.30 g/cm3
0.512
41
👆🏻
Tensile Strength
445.00 MPa689.00 MPa
0.1
11000
👆🏻
Viscosity
0.000.00
1.5E-05
0.0035
👆🏻
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)0.00 (Pa)
0
121
👆🏻
Vapor Pressure at 2000 K
0.00 (Pa)774.00 (Pa)
0
774
👆🏻
Elasticity properties
Shear Modulus
30.00 GPa115.00 GPa
1.3
222
👆🏻
Bulk Modulus
110.00 GPa160.00 GPa
0
462
👆🏻
Young's Modulus
78.00 GPa279.00 GPa
0
528
👆🏻
Poisson Ratio
0.370.21
0.032
0.47
👆🏻
Other Mechanical Properties
Ductile, Malleable
-
Magnetic Characteristics
Specific Gravity
13.317.19
0.53
4500
👆🏻
Magnetic Ordering
Paramagnetic
Antiferromagnetic
Permeability
0.00 H/m0.00 H/m
1.25643E-06
0.0063
👆🏻
Susceptibility
0.000.00
-0.000166
200000
👆🏻
Electrical Properties
Electrical Property
Conductor
-
Resistivity
331.00 nΩ·m125.00 nΩ·m
0.1
961
👆🏻
Electrical Conductivity
0.03 106/cm Ω0.08 106/cm Ω
0
0.63
👆🏻
Electron Affinity
0.00 kJ/mol64.30 kJ/mol
0
222.8
👆🏻
Specific Heat
0.14 J/(kg K)0.45 J/(kg K)
0.1
3.6
👆🏻
Molar Heat Capacity
25.73 J/mol·K23.35 J/mol·K
13.1
62.7
👆🏻
Thermal Conductivity
23.00 W/m·K93.90 W/m·K
0
429
👆🏻
Critical Temperature
2,500.00 K1,907.00 K
26.3
3695
👆🏻
Thermal Expansion
5.90 µm/(m·K)4.90 µm/(m·K)
4.5
97
👆🏻
Enthalpy
Enthalpy of Vaporization
661.10 kJ/mol348.80 kJ/mol
7.32
799.1
👆🏻
Enthalpy of Fusion
25.10 kJ/mol15.31 kJ/mol
2.1
35.23
👆🏻
Enthalpy of Atomization
703.00 kJ/mol397.50 kJ/mol
61.5
837
👆🏻
Standard Molar Entropy
43.60 J/mol.K23.80 J/mol.K
9.5
198.1
👆🏻