Science, Tech, Math › Science 10 Cool Facts About Lithium It's the lightest metal and imparts a crimson color to flame Share Flipboard Email Print Bloomberg Creative Photos / Getty Images Science Chemistry Periodic Table Basics Chemical Laws Molecules Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated November 03, 2019 Here are some facts about lithium, which is element atomic number 3 on the periodic table. Lithium Facts and History What we know about lithium: Lithium is the third element in the periodic table, with three protons and the element symbol Li. It has an atomic mass of 6.941. Natural lithium is a mixture of two stable isotopes, lithium-6 and lithium-7. Lithium-7 accounts for over 92% of the natural abundance of the element.Lithium is an alkali metal. It's silver-white in pure form and is so soft it can be cut with a butter knife. It has one of the lowest melting points and a high boiling point for a metal.Lithium metal burns white, though it imparts a crimson color to a flame. This is the characteristic that led to its discovery as an element. In the 1790s, it was known that the mineral petalite (LiAISi4O10) burned crimson in a fire. By 1817, the Swedish chemist Johan August Arfvedson had determined that the mineral contained an unknown element responsible for the colored flame. Arfvedson named the element, although he was unable to purify it as a pure metal. It wasn't until 1855 that British chemist Augustus Matthiessen and German chemist Robert Bunsen finally managed to purify lithium from lithium chloride.Lithium doesn't occur free in nature, though it is found in nearly all igneous rocks and in mineral springs. It was one of three elements produced by the big bang, along with hydrogen and helium. However, the pure element is so reactive it's only found naturally bonded to other elements to form compounds. The natural abundance of the element in the Earth's crust is about 0.0007%. One of the mysteries surrounding lithium is that the amount of lithium believed to have been produced by the big bang is about three times higher than what scientists see in the oldest stars. In the solar system, lithium is much less common than 25 of the first 32 chemical elements, probably because the atomic nucleus of lithium is practically unstable, with two stable isotopes possessing extremely low binding energies per nucleon.Pure lithium metal is extremely corrosive and requires special handling. Because it reacts with air and water, the metal is stored under oil or enclosed in an inert atmosphere. When lithium catches fire, the reaction with oxygen makes it difficult to extinguish the flames.Lithium is the lightest metal and the least dense solid element, with a density of about half that of water. In other words, if lithium didn't react with water (which it does, somewhat vigorously), it would float.Among other uses, lithium is employed in medicine, as a heat transfer agent, for making alloys, and for batteries. Although lithium compounds are known to stabilize mood, scientists still don't know the exact mechanism for the effect on the nervous system. What is known is that it reduces the activity of the receptor for the neurotransmitter dopamine and that it can cross the placenta to affect an unborn child.The transmutation of lithium to tritium was the first man-made nuclear fusion reaction.The name for lithium comes from the Greek lithos, which means stone. Lithium occurs in most igneous rocks, although it doesn't occur free in nature.Lithium metal is made by electrolysis of fused lithium chloride.