Lithium - Li
Lithium (Li) is a soft, silvery alkali metal with atomic number 3. It is important in batteries, industrial materials and water chemistry.
Properties and reactions · Uses · Health and safety · Environment and water
| Atomic number | 3 |
|---|---|
| Standard atomic weight | [6.938, 6.997]; approximately 6.94 for general calculations |
| Electronegativity (Pauling scale) | 0.98 |
| Density at 20 °C | 0.534 g cm−3 |
| Melting point | 180.50 °C |
| Boiling point | 1342 °C |
| Non-bonded atomic radius | 0.182 nm |
| Common ion | Li+ |
| Stable isotopes | 6Li and 7Li |
| Electron configuration | 1s22s1, or [He] 2s1 |
| First ionization energy | 520.2 kJ mol−1 |
| Discovery | Johan August Arfvedson, 1817 |
Property sources: Royal Society of Chemistry and CIAAW. Atomic weight varies with isotope composition; an isotope's mass number is written before its symbol as a superscript.
Properties and reactions of lithium
Lithium is the lightest metal. Its naturally occurring stable isotopes are 6Li and 7Li. The metal reacts with air and moisture and is not found uncombined in natural waters or ordinary mineral deposits. Its chemistry commonly involves the singly charged lithium ion, Li+.
Lithium reacts with water to form lithium hydroxide and flammable hydrogen. This reaction can cause fire and chemical burns:
2Li + 2H2O → 2LiOH + H2
Lithium also reacts with nitrogen to form lithium nitride (Li3N). Lithium metal, lithium salts and lithium-containing battery materials have different properties and hazards.
Uses of lithium
Batteries are the dominant use of lithium. Applications include rechargeable batteries for electric vehicles, portable electronics and energy storage. Lithium carbonate and lithium hydroxide are important feedstocks for battery materials; conventional lithium-ion batteries should not be confused with batteries containing a lithium-metal anode.
Other uses include glass and ceramics, lubricating greases made with lithium soaps, and lightweight alloys with aluminium. Lithium chloride and lithium bromide absorb moisture and are used in drying or absorption systems.
Some lithium salts are prescribed as mood stabilisers, particularly for bipolar disorder. Treatment requires clinical supervision and monitoring of lithium levels, kidney function and thyroid function; this use does not establish that lithium in drinking water is beneficial or harmless.
Occurrence and production
Commercial lithium is obtained from mineral deposits, including spodumene-bearing rock, and lithium-rich brines. Sources and extraction methods vary by deposit. Australia, China, Chile and Argentina are significant producers.
The USGS Mineral Commodity Summaries 2026 estimates 2025 world mine production at approximately 290,000 metric tonnes of contained lithium, excluding US production, and world reserves at approximately 37 million metric tonnes of contained lithium. These are dated estimates, not masses of lithium ore or lithium carbonate. Reserves and total geological resources are different measures.
Health effects and safe handling of lithium
Lithium metal is water-reactive and flammable. Its reaction with water produces hydrogen and corrosive lithium hydroxide. Finely divided metal can ignite in air. Contact can injure the eyes, skin and respiratory tract; inhalation may cause delayed lung injury.
Handling and emergency measures must match the chemical form and the supplier's safety data sheet. A lithium-metal fire requires an extinguishing agent specifically suitable for that metal; water must not be applied directly to burning lithium metal. Seek urgent medical assistance after significant exposure or suspected burns.
The hazards of elemental lithium cannot be applied directly to trace Li+ in water. Likewise, medicine safety information is not a drinking-water limit. The EPA identifies important uncertainties in the health effects of long-term exposure to low concentrations in drinking water.
Lithium in the environment and water
Lithium occurs naturally in rocks, soils, brines and groundwater. In water it occurs as dissolved lithium ions, rather than pieces of reactive lithium metal. Mineral weathering and the local geology influence its concentration; industrial releases can also contribute. Environmental effects depend on chemical form, concentration and exposure.
For water-treatment engineers, lithium removal must be assessed as removal of a dissolved ion. Boiling and disinfection do not remove lithium. EPA research found high removal by reverse osmosis in the systems studied, while removal by conventional treatment, ion-exchange softening and lime softening was absent, variable or limited. Results depend on the process and water composition; the finished-water concentration also depends on any blending with untreated water.
Read more about lithium in water.
Related element profiles: cadmium, copper, manganese, nickel, tungsten, cerium, tin, nitrogen and oxygen.
Lithium page last reviewed: by Lenntech.
Back to the periodic table of elements.
Sources and further reading
- RSC: lithium properties, reactions, applications and history.
- CIAAW: lithium atomic weight and isotopes.
- USGS: Mineral Commodity Summaries 2026 — lithium (PDF).
- ILO/WHO: International Chemical Safety Card 0710 — lithium metal.
- NICE: clinical guidance on lithium treatment and monitoring.
- EPA: lithium in drinking water — technical fact sheet (PDF).
- EPA: pilot- and full-scale lithium-removal studies (2025).