Symbol
Ca
  
Rh
  
Period Number
4
  
5
  
Block
s block
  
d block
  
Element Family
Alkaline Earth
  
Transition Metal
  
Space Group Name
Fm_ 3m
  
Fm_ 3m
  
Interesting Facts
- Calcium ranks 5th rank in the list of earth’s abundance Percentage.
- It is found in the compound state.
- Gypsum or calcium sulfate is used as plaster and plaster of paris.
  
- 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
Earth's crust, Found in Minerals, Mining, Ores of Minerals
  
Earth's crust, Found As a By-product, Found in Minerals, Mining
  
History
  
  
Who Discovered
Humphry Davy
  
William Hyde Wollaston
  
Discovery
In 1808
  
In 1804
  
Abundance
  
  
Abundance In Sun
~0.0000002 %
  
25
Abundance In Earth's Crust
Abundance In Oceans
Not Available
  
Abundance In Humans
Not Available
  
Uses & Benefits
- It is used as a reducing agent while preparing metals like thorium and uranium. It is also used as an alloying agent for metals such as aluminum, copper & lead.
- Calcium carbonate or lime stone is used in cement.
  
- 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
Chemical Industry
  
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
  
Medical Uses
Dentistry, Pharmaceutical Industry
  
NA
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
Non Toxic
  
NA
  
Present in Human Body
Yes
  
No
  
In Blood
60.50 Blood/mg dm-3
  
4
Not Available
  
In Bone
170,000.00 p.p.m.
  
1
Not Available
  
Melting Point
1,966.00 °C
  
12
Boiling Point
1,484.00 °C
  
99+
3,727.00 °C
  
17
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Gray
  
Silvery White
  
Luster
NA
  
Metallic
  
Hardness
  
  
Brinell Hardness
170.00 MPa
  
99+
Vickers Hardness
Not Available
  
1,100.00 MPa
  
9
Speed of Sound
3,810.00 m/s
  
19
4,700.00 m/s
  
15
Optical Properties
  
  
Reflectivity
Not Available
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Ca
  
Rh
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Not Available
  
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
589.80 kJ/mol
  
99+
719.70 kJ/mol
  
29
2nd Energy Level
1,145.40 kJ/mol
  
99+
1,740.00 kJ/mol
  
26
3rd Energy Level
4,912.40 kJ/mol
  
7
2,997.00 kJ/mol
  
27
4th Energy Level
6,491.00 kJ/mol
  
7
Not Available
  
5th Energy Level
8,153.00 kJ/mol
  
7
Not Available
  
6th Energy Level
10,496.00 kJ/mol
  
8
Not Available
  
7th Energy level
12,270.00 kJ/mol
  
12
Not Available
  
8th Energy Level
14,206.00 kJ/mol
  
15
Not Available
  
9th Energy Level
18,191.00 kJ/mol
  
12
Not Available
  
10th Energy Level
20,385.00 kJ/mol
  
16
Not Available
  
11th Energy Level
57,110.00 kJ/mol
  
3
Not Available
  
12th Energy Level
63,410.00 kJ/mol
  
3
Not Available
  
13th Energy Level
70,110.00 kJ/mol
  
3
Not Available
  
14th Energy Level
78,890.00 kJ/mol
  
4
Not Available
  
15th Energy Level
86,310.00 kJ/mol
  
5
Not Available
  
16th Energy Level
94,000.00 kJ/mol
  
6
Not Available
  
17th Energy Level
104,900.00 kJ/mol
  
7
Not Available
  
18th Energy Level
111,711.00 kJ/mol
  
8
Not Available
  
Electrochemical Equivalent
0.75 g/amp-hr
  
99+
1.28 g/amp-hr
  
99+
Other Chemical Properties
Chemical Stability, Flammability, Ionization, Solubility
  
Anti Corrosion, Ionization, Radioactive Isotopes
  
Electron Configuration
[Ar] 4s2
  
[Kr] 4d8 5s1
  
Crystal Structure
Face Centered Cubic (FCC)
  
Face Centered Cubic (FCC)
  
Crystal Lattice
FCC-Crystal-Structure-of-Calcium.jpg#100
  
FCC-Crystal-Structure-of-Rhodium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Weight
102.91 amu
  
99+
Atomic Volume
29.90 cm3/mol
  
7
8.30 cm3/mol
  
99+
Adjacent Atomic Numbers
  
  
Valence Electron Potential
29.00 (-eV)
  
99+
64.00 (-eV)
  
22
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
1.55 g/cm3
  
99+
12.41 g/cm3
  
28
Density When Liquid (at m.p.)
1.38 g/cm3
  
99+
10.70 g/cm3
  
14
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Vapor Pressure at 2000 K
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
NA
  
Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Diamagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
33.60 nΩ·m
  
99+
43.30 nΩ·m
  
99+
Electrical Conductivity
0.30 106/cm Ω
  
6
0.21 106/cm Ω
  
8
Electron Affinity
2.37 kJ/mol
  
39
109.70 kJ/mol
  
7
Specific Heat
0.63 J/(kg K)
  
7
0.24 J/(kg K)
  
22
Molar Heat Capacity
25.93 J/mol·K
  
34
24.98 J/mol·K
  
99+
Thermal Conductivity
201.00 W/m·K
  
5
150.00 W/m·K
  
9
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
22.30 µm/(m·K)
  
19
8.20 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
150.00 kJ/mol
  
99+
495.40 kJ/mol
  
12
Enthalpy of Fusion
8.54 kJ/mol
  
99+
21.76 kJ/mol
  
10
Enthalpy of Atomization
184.00 kJ/mol
  
99+
556.50 kJ/mol
  
12
Standard Molar Entropy
41.60 J/mol.K
  
36
31.50 J/mol.K
  
99+