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Information valid for Sm-150 unless otherwise noted

Basic Information

Symbol: Sm
Atomic Number: 62
Mass: 150.36
Melting Point: 1072.0 C
Boiling Point: 1900.0 C
Number of Protons/Electrons: 62
Number of Neutrons: 88
Classification: Rare Earth
Crystal Structure: Rhombohedral
Density @ 293 K: 7.54 g/cm3
Color: silver

Atomic Structure

[Bohr Model of Samarium]
Number of Energy Levels: 6

  1. First Energy Level: 2
    Second Energy Level: 8
    Third Energy Level: 18
    Fourth Energy Level: 24
    Fifth Energy Level: 8
    Sixth Energy Level: 2


Isotope Half Life
Sm-144 Stable
Sm-145 340.0 days
Sm-146 1.03E8 years
Sm-147 1.06E11 years
Sm-148 7.0E15 years
Sm-149 Stable
Sm-150 Stable
Sm-151 90.0 years
Sm-152 Stable
Sm-153 1.92 days
Sm-154 Stable


Date of Discovery: 1879
Discoverer: Paul Emile Lecoq de Boisbaudran
Name Origin: smarskite (mineral)
Uses: No uses known
Obtained From: found with other rare earths