Rhodium vs Gold
Periodic Table
Symbol
Rh
Au
Group Number
9
9
11
7
Period Number
5
6
Block
d block
d block
Element Family
Transition Metal
Transition Metal
CAS Number
7440166
99+
7440575
31
Space Group Name
Fm_ 3m
Fm_ 3m
Space Group Number
225.00
2
225.00
2
Facts
Interesting Facts
- 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.
- It is found in copper ores and from the crust of the earth.
- It is the most malleable and ductile metal.
- Gold alloys are used in Dentistry as fillings, crowning, clips, etc. It is also used as an artificial limb joints.
Sources
Earth's crust, Found As a By-product, Found in Minerals, Mining
Earth's crust, Mining, Ores of metals
History
Who Discovered
William Hyde Wollaston
Unknown
Discovery
In 1804
Before 6000 BCE
Abundance
Abundance In Universe
6 * 10-8 %
26
6 * 10-8 %
26
Abundance In Sun
~0.0000002 %
25
~0.0000001 %
26
Abundance In Meteorites
0.00 %
36
0.00 %
99+
Abundance In Earth's Crust
0.00 %
99+
0.00 %
99+
Abundance In Oceans
Not Available
0.00 %
21
Abundance In Humans
Not Available
0.00 %
18
Uses
Uses & Benefits
- 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.
- Gold metal is mainly used for Jewelry, bullion, coinage, etc.
- It is used in the art, decoration, ornaments, etc. It is also used for electroplating process.
Industrial Uses
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Chemical Industry, Clothing Industry, Electrical Industry, Electronic Industry
Medical Uses
NA
Dentistry, Pharmaceutical Industry
Other Uses
Alloys
Alloys, Bullion, Coinage, Jewellery, Sculptures, Statues
Biological Properties
Toxicity
NA
Non Toxic
Present in Human Body
No
Yes
In Blood
Not Available
0.00 Blood/mg dm-3
35
In Bone
Not Available
0.02 p.p.m.
30
Physical Properties
Melting Point
1,966.00 °C
12
1,064.43 °C
99+
Boiling Point
3,727.00 °C
17
2,807.00 °C
36
Appearance
Physical State
Solid
Solid
Color
Silvery White
Gold
Luster
Metallic
Metallic
Hardness
Mohs Hardness
6.00
6
2.50
14
Brinell Hardness
980.00 MPa
9
194.00 MPa
99+
Vickers Hardness
1,100.00 MPa
9
216.00 MPa
31
Speed of Sound
4,700.00 m/s
15
2,030.00 m/s
99+
Optical Properties
Reflectivity
84.00 %
4
95.00 %
2
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
Rh
Au
Isotopes
Known Isotopes
16
23
36
3
Electronegativity
Pauling Electronegativity
2.28
3
2.54
1
Allred Rochow Electronegativity
1.45
16
1.42
18
Mulliken-Jaffe Electronegativity
Not Available
1.87
7
Allen Electronegativity
1.56
24
1.92
5
Electropositivity
Pauling Electropositivity
1.72
99+
1.46
99+
Ionization Energies
1st Energy Level
719.70 kJ/mol
29
890.10 kJ/mol
8
2nd Energy Level
1,740.00 kJ/mol
26
1,980.00 kJ/mol
12
3rd Energy Level
2,997.00 kJ/mol
27
Not Available
Electrochemical Equivalent
1.28 g/amp-hr
99+
2.45 g/amp-hr
21
Electron Work Function
4.98 eV
6
5.10 eV
4
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
Chemical Stability, Ionization, Solubility
Atomic Properties
Atomic Number
45
99+
79
37
Electron Configuration
[Kr] 4d8 5s1
[Xe] 4f14 5d10 6s1
Crystal Structure
Face Centered Cubic (FCC)
Face Centered Cubic (FCC)
Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100
FCC-Crystal-Structure-of-Gold.jpg#100
Atom
Number of Protons
45
99+
79
37
Number of Neutrons
58
99+
118
23
Number of Electrons
45
99+
79
37
Radius of an Atom
Atomic Radius
134.00 pm
99+
151.00 pm
32
Covalent Radius
142.00 pm
99+
144.00 pm
40
Van der Waals Radius
200.00 pm
28
166.00 pm
39
Atomic Weight
102.91 amu
99+
196.97 amu
33
Atomic Volume
8.30 cm3/mol
99+
10.20 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
64.00 (-eV)
22
43.40 (-eV)
99+
Lattice Constant
380.34 pm
27
407.82 pm
21
Lattice Angles
π/2, π/2, π/2
π/2, π/2, π/2
Lattice C/A Ratio
Not Available
1.61
4
Mechanical Properties
Density
Density At Room Temperature
12.41 g/cm3
28
19.30 g/cm3
15
Density When Liquid (at m.p.)
10.70 g/cm3
14
17.31 g/cm3
6
Tensile Strength
951.00 MPa
5
120.00 MPa
15
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
0.00 (Pa)
23
Vapor Pressure at 2000 K
0.02 (Pa)
19
67.00 (Pa)
4
Elasticity properties
Shear Modulus
150.00 GPa
6
27.00 GPa
27
Bulk Modulus
275.00 GPa
5
180.00 GPa
9
Young's Modulus
380.00 GPa
5
79.00 GPa
24
Poisson Ratio
0.26
22
0.40
4
Other Mechanical Properties
Malleable
Ductile, Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
12.41
20
19.32
8
Magnetic Ordering
Paramagnetic
Diamagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
43.30 nΩ·m
99+
2.20 nΩ·m
99+
Electrical Conductivity
0.21 106/cm Ω
8
0.45 106/cm Ω
3
Electron Affinity
109.70 kJ/mol
7
222.80 kJ/mol
1
Thermal Properties
Specific Heat
0.24 J/(kg K)
22
0.13 J/(kg K)
39
Molar Heat Capacity
24.98 J/mol·K
99+
25.42 J/mol·K
40
Thermal Conductivity
150.00 W/m·K
9
318.00 W/m·K
3
Critical Temperature
Not Available
Not Available
Thermal Expansion
8.20 µm/(m·K)
99+
14.20 µm/(m·K)
26
Enthalpy
Enthalpy of Vaporization
495.40 kJ/mol
12
324.40 kJ/mol
27
Enthalpy of Fusion
21.76 kJ/mol
10
12.55 kJ/mol
27
Enthalpy of Atomization
556.50 kJ/mol
12
364.00 kJ/mol
25
Standard Molar Entropy
31.50 J/mol.K
99+
47.40 J/mol.K
32
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