Lithium

About Lithium

Lithium is the lightest metal on the table — density 0.534 g/cm³, light enough to float on mineral oil, which is exactly how labs store it to keep it away from air. As the first alkali metal, it has one 2s electron to lose, but it loses it more reluctantly than its bigger cousins down group 1. That small ionic radius gives Li⁺ a much higher charge density than Na⁺ or K⁺, which is why lithium compounds show some unusual behavior: LiF is barely soluble while NaF is, lithium forms a normal oxide instead of a peroxide on burning, and lithium salts give a clean crimson flame test. The electrochemistry is what made the modern world: Li⁰ → Li⁺ + e⁻ has a standard reduction potential of -3.04 V, the most negative of any element, which is why Li-ion cells deliver high voltage in a light package. Lithium carbonate has been used as a mood stabilizer in bipolar disorder since John Cade's 1949 paper. Most of the supply now comes from brine ponds in the Atacama and hard-rock spodumene mines in Western Australia.