Lithium: the first metal in the periodic table

How it was discovered and where it's used

Lithi­um is the third el­e­ment in the pe­ri­od­ic ta­ble, and is an al­ka­line met­al. It has a sil­very-white col­or. Lithi­um is so soft that it can eas­i­ly be cut with a knife, and has the low­est den­si­ty of all met­als – 0.533 g/cm³ – al­most twice as light as wa­ter, which means that it floats in wa­ter. Lithi­um has the high­est melt­ing and boil­ing points of all al­ka­line met­als: 180.54 and 1340 °C, re­spec­tive­ly. Com­pared with its neigh­bors in the group, lithi­um is the least re­ac­tive, and does not re­act so ac­tive­ly with wa­ter and air.

Where lithi­um is en­coun­tered

Lithi­um has two sta­ble iso­topes – lithi­um-6 and lithi­um-7 – and was among the first three el­e­ments formed in the first sec­onds af­ter the Big Bang. Now it is con­tained in greater quan­ti­ties in young stars, while old stars seem to have less lithi­um than they should. This may be be­cause in old stars lithi­um “mix­es” into the in­te­ri­or of the star, where it is de­stroyed. There is a con­sid­er­able quan­ti­ty of lithi­um in or­ange stars and brown dwarfs.

Lithi­um is wide­spread on Earth, but only found in bond­ed form be­cause of its re­ac­tiv­i­ty. Its con­tent in sea­wa­ter is 0.14 – 0.25 ppm, and up to 7 ppm near hy­dro­ther­mal vents. There are rare nat­u­ral springs of min­er­al wa­ter with high lithi­um con­tent. This “lithi­um brine” is called lithia. Lithi­um is the 25th most abun­dant el­e­ment in the earth’s crust. The main min­er­als that con­tain lithi­um are spo­dumene, petal­ite, lep­i­do­lite and hec­torite clay.

How lithi­um was dis­cov­ered

In 1800, the Brazil­ian chemist and states­man José Bonifá­cio de An­drade e Sil­va dis­cov­ered petal­ite (LiAl­Si₄O₁₀) in a mine on the is­land of Utö, Swe­den. While study­ing petal­ite ore in the lab­o­ra­to­ry of Berzelius, the Swedish chemist Jo­han Au­gust Ar­fwed­son de­tect­ed the pres­ence of a new el­e­ment. This el­e­ment had prop­er­ties sim­i­lar to sodi­um and potas­si­um, but its car­bon­ate and hy­drox­ide were less sol­u­ble in wa­ter and more al­ka­line. Berzelius pro­posed to call it “lithion” or “lithi­na” from the Greek “λιθoς” – stone. He lat­er de­cid­ed to call the met­al lithi­um. Ar­fwed­son con­tin­ued to study var­i­ous min­er­als, and showed that lithi­um was con­tained in spo­dumene and lep­i­do­lite.

In 1818, the Ger­man chemist Chris­tain Gmelin dis­cov­ered that lithi­um salts turned flames bright red. Both Ar­fwed­son and Gmelin un­suc­cess­ful­ly tried to ex­tract pure lithi­um, but with no re­sult. It was not ex­tract­ed un­til 1821, by William Thomas Brande in Eng­land, who be­came a chemist af­ter he met Humphry Davy. Brande used the method em­ployed by Davy to ex­tract sodi­um and potas­si­um – elec­trol­y­sis. From lithi­um ox­ide, Brande ob­tained pure lithi­um. Ad­di­tion­al­ly, he de­scribed some pure salts of lithi­um, such as the chlo­ride, and es­ti­mat­ed the atom­ic weight of lithi­um, if some­what in­cor­rect­ly: 9.8 in­stead of 6.94 g/mol.

Where lithi­um is used

Lithi­um found its first ap­pli­ca­tion in avi­a­tion dur­ing WWII, and lat­er as a high-tem­per­a­ture en­gine lu­bri­cant. Dur­ing the Cold War, lithi­um-6 and lithi­um-7 iso­topes were used in cre­at­ing the hy­dro­gen bomb, as they pro­duce tri­tium when ir­ra­di­at­ed by neu­trons. Lithi­um deu­teride was used as sol­id fu­sion fuel in hy­dro­gen bombs. Af­ter the nu­cle­ar arms race came to an end, the pro­duc­tion of lithi­um de­creased some­what.

A new phase in the his­to­ry of lithi­um use came from the de­vel­op­ment and mar­ket­ing of lithi­um ion bat­ter­ies in the late 20th cen­tu­ry. Lithi­um has a low atom­ic mass with a high po­ten­tial of elec­trodes and a high en­er­gy-to-weight ra­tio. There are both charge­able lithi­um ion bat­ter­ies and dis­pos­able lithi­um bat­ter­ies, in which lithi­um acts as the an­ode. Oth­er spheres in which lithi­um is used in­clude the man­u­fac­ture of ce­ram­ics and glaz­ing, met­al­lur­gy, where lithi­um is used in com­pounds in pro­cess­es of forg­ing iron, treat­ing alu­minum, weld­ing and sol­der­ing, as a flux. Lithi­um hy­drox­ide and per­ox­ide are used for pu­ri­fy­ing air of car­bon diox­ide, and also for pro­duc­ing oxy­gen from CO₂ and lithi­um per­ox­ide, a process which is used on space­craft and in sub­marines. Lithi­um flu­o­ride is used in IR, UV and vac­u­um UV op­tics. If fine­ly di­vid­ed lithi­um flu­o­ride pow­der is ex­posed to ra­di­a­tion, it re­leas­es a bluish light, whose in­ten­si­ty is pro­por­tion­al to the ab­sorbed dose. Lithi­um flu­o­ride is used in this way in the ther­mo­lu­min­scent ra­di­a­tion dosime­try. It is also used in tele­scope lens­es.

Lithi­um alu­minum hy­dride, lithi­um tri­ethyl­boro­hy­dride, n- and tert-butyl­lithi­um are wide­ly used re­duc­ing agents in or­gan­ic chem­istry.

Ad­di­tion­al­ly, lithi­um alu­minum hy­dride is used as rock­et fuel for mil­i­tary pur­pos­es. Lithi­um car­bon­ate was the first mood-sta­bi­liz­ing drug to re­duce symp­toms of af­fec­tive dis­or­ders (man­ic and hy­po­man­ic phas­es of bipo­lar dis­or­der), and also to treat de­pres­sion. Lat­er oth­er lithi­um salts also be­gan to be used in medicine: lithi­um cit­rate, suc­ci­nate, oro­tate, chlo­ride and sul­fate. There is some ev­i­dence that the heal­ing prop­er­ties of lithi­um salts were first dis­cov­ered in the 2nd cen­tu­ry BCE, when the doc­tor So­ranus of Eph­esus treat­ed pa­tients suf­fer­ing from “ma­nia” and “melan­choly” with al­ka­line wa­ter with a high lithi­um con­tent.

In 1920, Charles Leiper Grigg in­vent­ed a for­mu­la for a lemon-lime soft drink and called it “Bib-La­bel Lithi­at­ed Lemon-Lime Soda”. It con­tained lithi­um cit­rate and was patent­ed as a medicine prod­uct. All Amer­i­can bev­er­age mak­ers were sub­se­quent­ly forced to re­move lithi­um ad­di­tives from their prod­ucts. The drink was soon changed to “7 Up”.