Scandium vs Chromium
Periodic Table
Symbol
Sc
Cr
Group Number
3
15
6
12
Period Number
4
4
Block
d block
d block
Element Family
Transition Metal
Transition Metal
CAS Number
7440202
99+
7440473
39
Space Group Name
P63/mmc
Im_ 3m
Space Group Number
194.00
5
229.00
1
Facts
Interesting Facts
- Scandium is known as one of the rare earth elements.
- Scandium metal found in rare minerals called Wolframite .
- 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 in Minerals, Mining, Ores of metals, Ores of Minerals
Found in Minerals, Mining, Ores of metals, Ores of Minerals
History
Who Discovered
Lars Fredrik Nilson
Louis Nicolas Vauquelin
Discovery
In 1879
In Between 1797 - 1798
Abundance
Abundance In Universe
3 * 10-6 %
15
1.5 * 10-3 %
7
Abundance In Sun
~0.000004 %
16
~0.002 %
7
Abundance In Meteorites
0.00 %
18
0.30 %
7
Abundance In Earth's Crust
0.00 %
23
0.01 %
13
Abundance In Oceans
0.00 %
32
0.00 %
16
Abundance In Humans
Not Available
0.00 %
16
Uses
Uses & Benefits
- Uses of Scandium are limited to research purpose only. However, it has very low density and higher melting point.
- Its compounds like scandium iodide is used in mercury vapor lamps to produce very bright white light.
- 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
Electrical Industry, Electronic Industry
Automobile Industry, Chemical Industry
Medical Uses
NA
NA
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Non Toxic
Highly Toxic
Present in Human Body
Yes
Yes
In Blood
0.01 Blood/mg dm-3
22
0.11 Blood/mg dm-3
12
In Bone
0.00 p.p.m.
34
0.33 p.p.m.
21
Physical Properties
Melting Point
1,539.00 °C
24
1,857.00 °C
14
Boiling Point
2,832.00 °C
35
2,672.00 °C
39
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silver
Luster
Lustrous
Metallic
Hardness
Mohs Hardness
Not Available
8.50
1
Brinell Hardness
750.00 MPa
12
687.00 MPa
16
Vickers Hardness
Not Available
1,060.00 MPa
10
Speed of Sound
Not Available
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 Properties
Chemical Formula
Sc
Cr
Isotopes
Known Isotopes
13
26
21
18
Electronegativity
Pauling Electronegativity
1.36
29
1.66
18
Sanderson Electronegativity
1.02
21
1.66
14
Allred Rochow Electronegativity
1.20
27
1.56
10
Allen Electronegativity
1.19
36
1.65
19
Electropositivity
Pauling Electropositivity
2.64
25
2.34
36
Ionization Energies
1st Energy Level
633.10 kJ/mol
99+
26,130.00 kJ/mol
1
2nd Energy Level
1,235.00 kJ/mol
99+
28,750.00 kJ/mol
1
3rd Energy Level
2,388.60 kJ/mol
99+
34,230.00 kJ/mol
1
4th Energy Level
7,090.60 kJ/mol
6
37,066.00 kJ/mol
1
5th Energy Level
8,843.00 kJ/mol
6
97,510.00 kJ/mol
1
6th Energy Level
10,679.00 kJ/mol
7
105,800.00 kJ/mol
1
7th Energy level
13,310.00 kJ/mol
8
114,300.00 kJ/mol
1
8th Energy Level
15,250.00 kJ/mol
11
125,300.00 kJ/mol
1
9th Energy Level
17,370.00 kJ/mol
14
134,700.00 kJ/mol
1
10th Energy Level
21,726.00 kJ/mol
13
144,300.00 kJ/mol
1
11th Energy Level
24,102.00 kJ/mol
16
26,130.00 kJ/mol
12
12th Energy Level
66,320.00 kJ/mol
2
28,750.00 kJ/mol
13
13th Energy Level
73,010.00 kJ/mol
2
34,230.00 kJ/mol
10
14th Energy Level
80,160.00 kJ/mol
3
37,066.00 kJ/mol
12
15th Energy Level
89,490.00 kJ/mol
4
97,510.00 kJ/mol
1
16th Energy Level
97,400.00 kJ/mol
5
105,800.00 kJ/mol
2
17th Energy Level
105,600.00 kJ/mol
6
114,300.00 kJ/mol
3
18th Energy Level
117,000.00 kJ/mol
7
125,300.00 kJ/mol
4
19th Energy Level
124,270.00 kJ/mol
8
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
0.56 g/amp-hr
99+
0.32 g/amp-hr
99+
Electron Work Function
3.50 eV
31
4.50 eV
14
Other Chemical Properties
Corrosion, Flammable, Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
21
99+
24
99+
Electron Configuration
[Ar] 3d1 4s2
[Ar] 3d5 4s1
Crystal Structure
Hexagonal Close Packed (HCP)
Body Centered Cubic (BCC)
Crystal Lattice
HCP-Crystal-Structure-of-Scandium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
21
99+
24
99+
Number of Neutrons
24
99+
28
99+
Number of Electrons
21
99+
24
99+
Radius of an Atom
Atomic Radius
162.00 pm
26
128.00 pm
99+
Covalent Radius
170.00 pm
25
139.00 pm
99+
Van der Waals Radius
211.00 pm
25
200.00 pm
28
Atomic Weight
44.96 amu
99+
52.00 amu
99+
Atomic Volume
15.00 cm3/mol
34
7.23 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
58.00 (-eV)
24
170.00 (-eV)
4
Lattice Constant
330.90 pm
99+
291.00 pm
99+
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.59
7
Not Available
Mechanical Properties
Density
Density At Room Temperature
2.99 g/cm3
99+
7.19 g/cm3
99+
Density When Liquid (at m.p.)
2.80 g/cm3
99+
6.30 g/cm3
40
Tensile Strength
Not Available
689.00 MPa
7
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
22
0.00 (Pa)
24
Vapor Pressure at 2000 K
91.30 (Pa)
3
774.00 (Pa)
1
Elasticity properties
Shear Modulus
29.10 GPa
24
115.00 GPa
9
Bulk Modulus
56.60 GPa
21
160.00 GPa
11
Young's Modulus
74.40 GPa
26
279.00 GPa
8
Poisson Ratio
0.28
18
0.21
32
Other Mechanical Properties
NA
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
2.99
99+
7.19
99+
Magnetic Ordering
Paramagnetic
Antiferromagnetic
Electrical Properties
Electrical Property
Conductor
NA
Resistivity
562.00 nΩ·m
10
125.00 nΩ·m
27
Electrical Conductivity
0.02 106/cm Ω
99+
0.08 106/cm Ω
25
Electron Affinity
18.10 kJ/mol
33
64.30 kJ/mol
15
Thermal Properties
Specific Heat
0.60 J/(kg K)
8
0.45 J/(kg K)
12
Molar Heat Capacity
25.52 J/mol·K
37
23.35 J/mol·K
99+
Thermal Conductivity
15.80 W/m·K
99+
93.90 W/m·K
17
Critical Temperature
Not Available
Not Available
Thermal Expansion
10.20 µm/(m·K)
39
4.90 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
314.20 kJ/mol
28
348.80 kJ/mol
24
Enthalpy of Fusion
14.10 kJ/mol
25
15.31 kJ/mol
20
Enthalpy of Atomization
343.00 kJ/mol
28
397.50 kJ/mol
21
Standard Molar Entropy
34.60 J/mol.K
99+
23.80 J/mol.K
99+
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