Chromium Rubidium Comparison
Periodic Table
Symbol
Cr
Rb
Group Number
6
12
1
17
Period Number
4
5
Block
d block
s block
Element Family
Transition Metal
Alkali
CAS Number
7440473
39
7440177
99+
Space Group Name
Im_ 3m
Im_ 3m
Space Group Number
229.00
1
229.00
1
Facts
Interesting Facts
- 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.
- Rubidium metal is 16th most common element found in the earth crust.
- Rubidium metal also found in minerals as well as seawater.
Sources
Found in Minerals, Mining, Ores of metals, Ores of Minerals
Obtained from Lithium Production.
History
Who Discovered
Louis Nicolas Vauquelin
Robert Bunsen and Gustav Kirchhoff
Discovery
In Between 1797 - 1798
In 1861
Abundance
Abundance In Universe
1.5 * 10-3 %
7
1 * 10-6 %
16
Abundance In Sun
~0.002 %
7
~0.000003 %
17
Abundance In Meteorites
0.30 %
7
0.00 %
19
Abundance In Earth's Crust
0.01 %
13
0.01 %
18
Abundance In Oceans
0.00 %
16
0.00 %
7
Abundance In Humans
0.00 %
16
0.00 %
7
Uses
Uses & Benefits
- 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.
- Rubidium's main application is in the glass manufacturing.
- Rubidium can very easily get ionized and hence it is used for ion engines, but it is still less efficient than that of Caesium.
Industrial Uses
Automobile Industry, Chemical Industry
NA
Medical Uses
NA
NA
Other Uses
Alloys
Alloys, Research Purposes
Biological Properties
Toxicity
Highly Toxic
Non Toxic
Present in Human Body
Yes
Yes
In Blood
0.11 Blood/mg dm-3
12
2.49 Blood/mg dm-3
7
In Bone
0.33 p.p.m.
21
5.00 p.p.m.
13
Physical Properties
Melting Point
1,857.00 °C
14
38.89 °C
99+
Boiling Point
2,672.00 °C
39
688.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Silver
Grayish White
Luster
Metallic
NA
Hardness
Mohs Hardness
8.50
1
0.30
24
Brinell Hardness
687.00 MPa
16
0.22 MPa
99+
Vickers Hardness
1,060.00 MPa
10
Not Available
Speed of Sound
5,940.00 m/s
5
1,300.00 m/s
99+
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
Cr
Rb
Isotopes
Known Isotopes
21
18
29
10
Electronegativity
Pauling Electronegativity
1.66
18
0.82
99+
Sanderson Electronegativity
1.66
14
0.31
32
Allred Rochow Electronegativity
1.56
10
0.89
40
Mulliken-Jaffe Electronegativity
Not Available
0.69
24
Allen Electronegativity
1.65
19
0.71
99+
Electropositivity
Pauling Electropositivity
2.34
36
3.18
3
Ionization Energies
1st Energy Level
26,130.00 kJ/mol
1
403.00 kJ/mol
99+
2nd Energy Level
28,750.00 kJ/mol
1
2,633.00 kJ/mol
6
3rd Energy Level
34,230.00 kJ/mol
1
3,860.00 kJ/mol
11
4th Energy Level
37,066.00 kJ/mol
1
5,080.00 kJ/mol
18
5th Energy Level
97,510.00 kJ/mol
1
6,850.00 kJ/mol
19
6th Energy Level
105,800.00 kJ/mol
1
8,140.00 kJ/mol
20
7th Energy level
114,300.00 kJ/mol
1
9,570.00 kJ/mol
20
8th Energy Level
125,300.00 kJ/mol
1
13,120.00 kJ/mol
17
9th Energy Level
134,700.00 kJ/mol
1
14,500.00 kJ/mol
18
10th Energy Level
144,300.00 kJ/mol
1
26,740.00 kJ/mol
6
11th Energy Level
26,130.00 kJ/mol
12
Not Available
12th Energy Level
28,750.00 kJ/mol
13
Not Available
13th Energy Level
34,230.00 kJ/mol
10
Not Available
14th Energy Level
37,066.00 kJ/mol
12
Not Available
15th Energy Level
97,510.00 kJ/mol
1
Not Available
16th Energy Level
105,800.00 kJ/mol
2
Not Available
17th Energy Level
114,300.00 kJ/mol
3
Not Available
18th Energy Level
125,300.00 kJ/mol
4
Not Available
19th Energy Level
134,700.00 kJ/mol
5
Not Available
20th Energy Level
144,300.00 kJ/mol
7
Not Available
21st Energy Level
157,700.00 kJ/mol
7
Not Available
22nd Energy Level
166,090.00 kJ/mol
6
Not Available
Electrochemical Equivalent
0.32 g/amp-hr
99+
3.19 g/amp-hr
14
Electron Work Function
4.50 eV
14
2.16 eV
99+
Other Chemical Properties
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
Corrosion, Ionization, Radioactive Isotopes, Radioactivity
Atomic Properties
Atomic Number
24
99+
37
99+
Electron Configuration
[Ar] 3d5 4s1
[Kr] 5s1
Crystal Structure
Body Centered Cubic (BCC)
Body Centered Cubic (BCC)
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
24
99+
37
99+
Number of Neutrons
28
99+
48
99+
Number of Electrons
24
99+
37
99+
Radius of an Atom
Atomic Radius
128.00 pm
99+
248.00 pm
2
Covalent Radius
139.00 pm
99+
220.00 pm
4
Van der Waals Radius
200.00 pm
28
303.00 pm
3
Atomic Weight
52.00 amu
99+
85.47 amu
99+
Atomic Volume
7.23 cm3/mol
99+
55.90 cm3/mol
2
Adjacent Atomic Numbers
Valence Electron Potential
170.00 (-eV)
4
9.47 (-eV)
99+
Lattice Constant
291.00 pm
99+
558.50 pm
10
Lattice Angles
π/2, π/2, π/2
π/2, π/2, π/2
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
7.19 g/cm3
99+
1.53 g/cm3
99+
Density When Liquid (at m.p.)
6.30 g/cm3
40
1.46 g/cm3
99+
Tensile Strength
689.00 MPa
7
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
24
Not Available
Vapor Pressure at 2000 K
774.00 (Pa)
1
Not Available
Elasticity properties
Shear Modulus
115.00 GPa
9
Not Available
Bulk Modulus
160.00 GPa
11
2.50 GPa
99+
Young's Modulus
279.00 GPa
8
2.40 GPa
99+
Poisson Ratio
0.21
32
Not Available
Other Mechanical Properties
NA
Ductile
Magnetic Properties
Magnetic Characteristics
Specific Gravity
7.19
99+
1.53
99+
Magnetic Ordering
Antiferromagnetic
Paramagnetic
Electrical Properties
Electrical Property
NA
Conductor
Resistivity
125.00 nΩ·m
27
128.00 nΩ·m
26
Electrical Conductivity
0.08 106/cm Ω
25
0.08 106/cm Ω
24
Electron Affinity
64.30 kJ/mol
15
46.90 kJ/mol
24
Thermal Properties
Specific Heat
0.45 J/(kg K)
12
0.36 J/(kg K)
17
Molar Heat Capacity
23.35 J/mol·K
99+
31.06 J/mol·K
5
Thermal Conductivity
93.90 W/m·K
17
58.20 W/m·K
26
Critical Temperature
Not Available
2,093.00 K
4
Thermal Expansion
4.90 µm/(m·K)
99+
90.00 µm/(m·K)
2
Enthalpy
Enthalpy of Vaporization
348.80 kJ/mol
24
69.20 kJ/mol
99+
Enthalpy of Fusion
15.31 kJ/mol
20
2.19 kJ/mol
99+
Enthalpy of Atomization
397.50 kJ/mol
21
82.00 kJ/mol
99+
Standard Molar Entropy
23.80 J/mol.K
99+
76.80 J/mol.K
5
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