Symbol
Cm
  
Pa
  
Group Number
Not Available
  
Not Available
  
Period Number
7
  
7
  
Block
f block
  
f block
  
Element Family
Actinide
  
Actinide
  
Space Group Name
Not Available
  
I4/mmm
  
Space Group Number
Not Available
  
Interesting Facts
- Curium metal does not occur free in nature.
- Curium metal is a synthetically produced metal.
  
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
  
Sources
Bombarding Plutonium with Helium Ions
  
Found in Uranium Ores, Mining, Ores of metals
  
History
  
  
Who Discovered
Glenn T. Seaborg, Ralph A. James, Albert Ghiorso
  
William Crookes
  
Discovery
In 1944
  
In 1900
  
Abundance
  
  
Abundance In Earth's Crust
Not Available
  
Abundance In Oceans
Not Available
  
Uses & Benefits
- Curium metal is used to provide power to electrical equipment for space missions.
  
- Currently known uses of Protactinium metal are limited to research purpose only.
  
Industrial Uses
NA
  
NA
  
Medical Uses
NA
  
NA
  
Other Uses
Research Purposes
  
NA
  
Biological Properties
  
  
Toxicity
Unknown
  
Highly Toxic
  
Present in Human Body
No
  
No
  
In Blood
0.00 Blood/mg dm-3
  
37
0.00 Blood/mg dm-3
  
37
In Bone
0.00 p.p.m.
  
36
0.00 p.p.m.
  
36
Melting Point
1,340.00 °C
  
34
1,568.00 °C
  
21
Boiling Point
3,110.00 °C
  
30
4,027.00 °C
  
12
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Silver
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Speed of Sound
Not Available
  
Not Available
  
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Cm
  
Pa
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
581.00 kJ/mol
  
99+
568.00 kJ/mol
  
99+
2nd Energy Level
1,196.00 kJ/mol
  
99+
1,128.00 kJ/mol
  
99+
3rd Energy Level
2,026.00 kJ/mol
  
99+
1,814.00 kJ/mol
  
99+
4th Energy Level
3,550.00 kJ/mol
  
99+
2,991.00 kJ/mol
  
99+
Electrochemical Equivalent
3.07 g/amp-hr
  
16
1.72 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes
  
Ionization, Radioactive Isotopes, Radioactivity
  
Electron Configuration
[Rn] 5f7 6d1 7s2
  
[Rn] 5f2 6d1 7s2
  
Crystal Structure
Double Hexagonal Close Packed (DHCP)
  
Tetragonal (TETR)
  
Crystal Lattice
DHCP-Crystal-Structure-of-Curium.jpg#100
  
TETR-Crystal-Structure-of-Protactinium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
18.28 cm3/mol
  
26
15.00 cm3/mol
  
34
Adjacent Atomic Numbers
  
  
Valence Electron Potential
44.50 (-eV)
  
38
92.00 (-eV)
  
11
Lattice Constant
Not Available
  
Lattice Angles
NA
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
13.51 g/cm3
  
25
15.37 g/cm3
  
20
Density When Liquid (at m.p.)
13.85 g/cm3
  
10
Not Available
  
Tensile Strength
Not Available
  
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Poisson Ratio
Not Available
  
Not Available
  
Other Mechanical Properties
Unknown
  
Unknown
  
Magnetic Characteristics
  
  
Magnetic Ordering
Antiferromagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Unknown
  
Conductor
  
Resistivity
177.00 nΩ·m
  
21
Electrical Conductivity
Not Available
  
0.05 10
6/cm Ω
  
34
Specific Heat
Not Available
  
0.12 J/(kg K)
  
40
Molar Heat Capacity
Not Available
  
Not Available
  
Thermal Conductivity
Not Available
  
47.00 W/m·K
  
32
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
Not Available
  
9.90 µm/(m·K)
  
40
Enthalpy
  
  
Enthalpy of Fusion
15.00 kJ/mol
  
21
12.34 kJ/mol
  
28
Standard Molar Entropy
Not Available
  
198.10 J/mol.K
  
1