Fr.: uranium enrichi
Fr.: uranium naturel
Uranium as found in nature. It contains 0.7% uranium-235, 99.3% uranium-238, and a trace of uranium-234 by weight.
Fr.: élément transuranien
An element beyond uranium in the periodic table, with atomic number greater than 92. Such elements do not occur in nature, but may be obtained by suitable nuclear reactions. They are all radioactive and members of the actinide group.
A radioactive metallic chemical element; symbol U. Atomic number 92; atomic weight 238.0289; melting point 1,132°C; boiling point 3,818°C; specific gravity 19.1 at 25°C. A radioactive element with 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.
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.
Fr.: hexafluorure d'uranium
A white solid compound of → uranium and → fluorine obtained by chemical treatment of U3O8 (yellow cake), forming a vapor at temperatures above 56°C. It contains both of the naturally occurring isotopes of uranium U-235 and U-238. The isotopes are separated on the basis of differences in their diffusion properties.