Holmium vs Rhodium
Periodic Table
Symbol
Ho
Rh
Group Number
Not Available
9
9
Period Number
6
5
Block
f block
d block
Element Family
Lanthanide
Transition Metal
CAS Number
7440600
29
7440166
99+
Space Group Name
P63/mmc
Fm_ 3m
Space Group Number
194.00
5
225.00
2
Facts
Interesting Facts
- Holmium metal is very soft and malleable.
- Holmium metal is well known for its corrosion resistivity.
- 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 in Minerals, Mining, Ores of Minerals
Earth's crust, Found As a By-product, Found in Minerals, Mining
History
Who Discovered
Marc Delafontaine
William Hyde Wollaston
Discovery
In 1878
In 1804
Abundance
Abundance In Universe
5 * 10-8 %
27
6 * 10-8 %
26
Abundance In Sun
~-9999 %
~0.0000002 %
25
Abundance In Meteorites
0.00 %
99+
0.00 %
36
Abundance In Earth's Crust
0.00 %
38
0.00 %
99+
Abundance In Oceans
0.00 %
99+
Not Available
Uses
Uses & Benefits
- Holmium metal has an ability to absorb neutrons, so this metal is used in nuclear reactors to keep the chain reactions of elements under control.
- Alloys of Holmium are used to produce Magnet.
- 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
NA
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Medical Uses
NA
NA
Other Uses
Alloys, Nuclear Research
Alloys
Biological Properties
Toxicity
Low Toxic
NA
Present in Human Body
No
No
Physical Properties
Melting Point
1,461.00 °C
30
1,966.00 °C
12
Boiling Point
2,600.00 °C
99+
3,727.00 °C
17
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silvery White
Luster
Metallic
Metallic
Hardness
Mohs Hardness
Not Available
6.00
6
Brinell Hardness
746.00 MPa
13
980.00 MPa
9
Vickers Hardness
481.00 MPa
23
1,100.00 MPa
9
Speed of Sound
2,760.00 m/s
30
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
Ho
Rh
Isotopes
Known Isotopes
34
5
16
23
Electronegativity
Pauling Electronegativity
1.23
37
2.28
3
Allred Rochow Electronegativity
1.10
30
1.45
16
Allen Electronegativity
Not Available
1.56
24
Electropositivity
Pauling Electropositivity
2.77
17
1.72
99+
Ionization Energies
1st Energy Level
581.00 kJ/mol
99+
719.70 kJ/mol
29
2nd Energy Level
1,140.00 kJ/mol
99+
1,740.00 kJ/mol
26
3rd Energy Level
2,204.00 kJ/mol
99+
2,997.00 kJ/mol
27
4th Energy Level
4,100.00 kJ/mol
34
Not Available
Electrochemical Equivalent
2.02 g/amp-hr
29
1.28 g/amp-hr
99+
Electron Work Function
Not Available
4.98 eV
6
Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Ionization, Radioactive Isotopes
Atomic Properties
Atomic Number
67
99+
45
99+
Electron Configuration
[Xe] 4f11 6s2
[Kr] 4d8 5s1
Crystal Structure
Hexagonal Close Packed (HCP)
Face Centered Cubic (FCC)
Crystal Lattice
HCP-Crystal-Structure-of-Holmium.jpg#100
FCC-Crystal-Structure-of-Rhodium.jpg#100
Atom
Number of Protons
67
99+
45
99+
Number of Neutrons
98
34
58
99+
Number of Electrons
67
99+
45
99+
Radius of an Atom
Atomic Radius
176.00 pm
18
134.00 pm
99+
Covalent Radius
192.00 pm
17
142.00 pm
99+
Van der Waals Radius
216.00 pm
24
200.00 pm
28
Atomic Weight
164.93 amu
99+
102.91 amu
99+
Atomic Volume
18.70 cm3/mol
24
8.30 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
47.90 (-eV)
31
64.00 (-eV)
22
Lattice Constant
357.73 pm
38
380.34 pm
27
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.57
17
Not Available
Mechanical Properties
Density
Density At Room Temperature
8.79 g/cm3
99+
12.41 g/cm3
28
Density When Liquid (at m.p.)
8.34 g/cm3
26
10.70 g/cm3
14
Tensile Strength
Not Available
951.00 MPa
5
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
16
Not Available
Vapor Pressure at 2000 K
Not Available
0.02 (Pa)
19
Elasticity properties
Shear Modulus
26.30 GPa
28
150.00 GPa
6
Bulk Modulus
40.20 GPa
32
275.00 GPa
5
Young's Modulus
64.80 GPa
31
380.00 GPa
5
Poisson Ratio
0.23
29
0.26
22
Other Mechanical Properties
Ductile, Malleable, Sectile
Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
8.80
35
12.41
20
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
814.00 nΩ·m
4
43.30 nΩ·m
99+
Electrical Conductivity
0.01 106/cm Ω
99+
0.21 106/cm Ω
8
Electron Affinity
50.00 kJ/mol
21
109.70 kJ/mol
7
Thermal Properties
Specific Heat
0.16 J/(kg K)
35
0.24 J/(kg K)
22
Molar Heat Capacity
27.15 J/mol·K
19
24.98 J/mol·K
99+
Thermal Conductivity
16.20 W/m·K
99+
150.00 W/m·K
9
Critical Temperature
Not Available
Not Available
Thermal Expansion
11.20 µm/(m·K)
35
8.20 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
241.00 kJ/mol
38
495.40 kJ/mol
12
Enthalpy of Fusion
11.76 kJ/mol
29
21.76 kJ/mol
10
Enthalpy of Atomization
301.00 kJ/mol
36
556.50 kJ/mol
12
Standard Molar Entropy
75.30 J/mol.K
8
31.50 J/mol.K
99+
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