Ytterbium

Ytterbium is a soft, silvery metallic chemical element with atomic number 70. It is a lanthanide whose atoms can exhibit both +2 and +3 oxidation states.

Electron configuration: The arrangement of electrons among an atom’s shells, subshells, and orbitals. Ytterbium’s filled 4f shell and two outer 6s electrons help explain its chemistry.
Optical lattice clock: An optical atomic clock that traps many atoms in a lattice formed by laser light. Ytterbium is a leading clock atom because its isotope transitions support precise measurements.
Jean Charles Galissard de Marignac: A Swiss chemist who discovered ytterbium in 1878 while studying erbium-containing minerals. His analysis of gadolinite identified a new rare-earth component later named ytterbium.
Lutetium: A dense lanthanide element with atomic number 71, immediately following ytterbium. Lutetium follows ytterbium in the series and has a different outer-electron configuration.
Oxidation state: A measure of an atom’s formal electron loss or gain in a compound. Ytterbium commonly forms +3 compounds and can also form +2 compounds.
Fiber laser: A laser in which light is amplified inside an optical fiber doped with active ions. Ytterbium-doped fiber lasers are a prominent high-power laser technology.
Gadolinite: A rare-earth silicate mineral that was central to the discovery of several elements. Marignac isolated the material he called ytterbia from gadolinite.
Thulium: A lanthanide element with atomic number 69, immediately preceding ytterbium. Thulium is a neighboring lanthanide whose chemistry helps frame ytterbium’s position in the series.
Lanthanide contraction: The gradual decrease in atomic and ionic size across the lanthanide series. It shapes ytterbium’s size and chemical behavior relative to neighboring lanthanides.
Laser cooling: The use of light to reduce the motion and temperature of atoms or particles. Laser cooling prepares ytterbium atoms for precision spectroscopy and optical clocks.

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Carl Auer von WelsbachRelated: Auer began with material then believed to be a single element and separated lutetium from it.