Lithium

Lithium is an element in the alkali metals class of the periodic table.^[1] It is the lightest solid element—about half the density of water. Like the other alkali metals, lithium reacts violently with water; it is usually stored in oil.

Lithium was discovered in petalite in 1817, and isolated in 1821 by W. T. Brand and Sir Humphrey Davy, by electrolyis of lithium oxide.

Uses[edit]

Lithium has rapidly grown in popularity as an electrode material in rechargeable batteries. Batteries which use lithium anodes/cathodes offer a higher power density that current alternatives, and a relatively good lifespan. Lithium carbonate is used in the treatment of bipolar disorder and some other mental health conditions.

Chemical Properties[edit]

Lithium melts at 453.69 Kelvin and boils at 1615K. In its solid form it is a silvery-white metal, soft enough to cut with a knife, but is usually covered in a grey surface coating due to oxidisation. Solid metallic lithium has a similar density to that of softwood. It is violently reactive in contact with water or acids.

Isotopes[edit]

There are two naturally occurring stable isotopes of lithium; ⁶Li and ⁷Li. 92.5% of lithium is ⁷Li. Seven radioisotopes have also been identified, but all have a half-life of under a second and are not found in nature.

Occurrence in Nature[edit]

Lithium is widely distributed in nature but, on Earth, is never found in elemental form due to its reactivity. It is estimated that lithium makes up between 20 and 70 parts per million (ppm) of Earth's crust, with the highest levels found in igneous rocks, especially granite. Seawater contains about 0.25ppm lithium.

Lithium is also found in some stars, although it is not common because the temperatures found in most stellar cores are sufficient to destroy it through a process in which a lithium atom and an H⁺ ion convert to two atoms of helium.

References[edit]

1. ↑ Wile, Dr. Jay L. Exploring Creation With Physical Science. Apologia Educational Ministries, Inc. 1999, 2000