Uranium

About Uranium

Uranium is the heaviest element you'll find in any meaningful quantity in the Earth's crust, and the chemistry of the actinides is largely the chemistry of how to handle it. Klaproth pulled it out of pitchblende in 1789 and named it after the recently discovered planet Uranus. The interesting fact for a working chemist is the isotope mix: natural uranium is 99.3% U-238 and only 0.72% U-235, and almost everything industrial about uranium revolves around shifting that ratio. Enrichment to ~3-5% U-235 happens via gaseous UF₆ in centrifuge cascades — UF₆ is one of the few uranium compounds volatile enough to spin (sublimes at 56 °C). Aqueous chemistry is dominated by the uranyl ion UO₂²⁺, a linear dioxocation that stays in the +6 oxidation state through most extraction and reprocessing flows (PUREX uses tributyl phosphate to pull uranyl nitrate into a kerosene phase). Reduce it to U(IV) and the chemistry inverts — UO₂ is the actual ceramic fuel pellet sitting inside reactor rods.