Samarium (Sm)

Samarium is a moderately hard silvery metal that slowly oxidizes in air.

Core Principles & Analysis

• Paul-Emile Lecoq de Boisbaudran isolated samarium in 1879 from the mineral samarskite, indirectly making it the first element named after a person.
• Samarium-cobalt magnets keep their magnetism at temperatures where neodymium magnets fail, remaining useful past 300 degrees Celsius.
• It serves in high-temperature aerospace magnets, and samarium-153 lexidronam relieves pain from cancer that has spread to bone.

Specifications & Metrics

• NUM: 62
• SYMBOL: Sm
• CATEGORY: Lanthanide
• ATOMIC MASS: 150.4 u
• ELECTRONEGATIVITY: 1.17 Pauling
• ATOMIC RADIUS: 229 pm
• IONIZATION ENERGY: 5.644 eV
• MELTING POINT: 1347 K
• BOILING POINT: 2067 K
• DENSITY: 7.52 g/cm³
• ELECTRON CONFIGURATION: [Xe]6s2 4f6
• OXIDATION STATES: +3, +2
• STANDARD STATE: Solid
• GROUP BLOCK: Lanthanide
• YEAR DISCOVERED: 1879