An Etymological Dictionary of Astronomy and Astrophysics

A → radioactive metallic → chemical element; symbol U. → Atomic number 92; → atomic weight 238.0289; → melting post 1,132 °C; → boiling point 3,818°C; → specific gravity 19.1 at 25 °C. Uranium has
14 known → isotopes of which ²³⁸U is the most abundant in nature. This isotope (→ half-life 4.5 billion years) is 138 times more abundant than ²³⁵U (half-life 710 million years). The metal was first isolated by the French chemist Eugène-Melchior Peligot in 1841. See also: → uranium oxide, → uranium conversion, → uranium dioxide, → uranium enrichment, → uranium hexafluoride, → uranium-233, → uranium-235, → uranium-238, → plutonium, → fissile isotope, → fertile isotope, → yellowcake.

See also: From the name of the planet → Uranus. The German chemist Martin-Heinrich Klaproth discovered the element in 1789, following the German/English astronomer William Hershel’s discovery of the planet in 1781.