Lithium reacts with water easily, but with noticeably less vigor than other alkali metals.
The reaction forms hydrogen gas and lithium hydroxide in aqueous solution.
Because of its reactivity with water, lithium is usually stored in a hydrocarbon sealant, often petroleum jelly.
Though the heavier alkali metals can be stored in denser substances such as mineral oil, lithium is not dense enough to fully submerge itself in these liquids.
In moist air, lithium rapidly tarnishes to form a black coating of lithium hydroxide (LiOH and LiOH·H₂O), lithium nitride (Li₃N) and lithium carbonate (Li₂CO₃, the result of a secondary reaction between LiOH and CO₂).

When placed over a flame, lithium compounds give off a striking crimson color, but when the metal burns strongly, the flame becomes a brilliant silver.
Lithium will ignite and burn in oxygen when exposed to water or water vapors.
Lithium is flammable, and it is potentially explosive when exposed to air and especially to water, though less so than the other alkali metals.
The lithium-water reaction at normal temperatures is brisk but nonviolent because the hydrogen produced does not ignite on its own.
As with all alkali metals, lithium fires are difficult to extinguish, requiring dry powder fire extinguishers (Class D type).
Lithium is one of the few metals that react with nitrogen under normal conditions.

Lithium has a diagonal relationship with magnesium, an element of similar atomic and ionic radius.
Chemical resemblances between the two metals include the formation of a nitride by reaction with N₂, the formation of an oxide (Li
₂O) and peroxide (Li
₂O
₂) when burnt in O₂, salts with similar solubilities, and thermal instability of the carbonates and nitrides.
The metal reacts with hydrogen gas at high temperatures to produce lithium hydride (LiH).

Other known binary compounds include halides (LiF, LiCl, LiBr, LiI), sulfide (Li
₂S), superoxide (LiO
₂), and carbide (Li
₂C
₂).
Many other inorganic compounds are known in which lithium combines with anions to form salts: borates, amides, carbonate, nitrate, or borohydride (LiBH
₄).
Lithium aluminium hydride (LiAlH
₄) is commonly used as a reducing agent in organic synthesis.

LiHe, a very weakly interacting van der Waals compound, has been detected at very low temperatures.

Unlike other elements in group 1, inorganic compounds of lithium follow the duet rule, rather than the octet rule.
Lithium reacts with water easily, but with noticeably less vigor than other alkali metals. The reaction forms hydrogen gas and lithium hydroxide in aqueous solution. Because of its reactivity with water, lithium is usually stored in a hydrocarbon sealant, often petroleum jelly. Though the heavier alkali metals can be stored in denser substances such as mineral oil, lithium is not dense enough to fully submerge itself in these liquids. In moist air, lithium rapidly tarnishes to form a black coating of lithium hydroxide (LiOH and LiOH·H₂O), lithium nitride (Li₃N) and lithium carbonate (Li₂CO₃, the result of a secondary reaction between LiOH and CO₂).
When placed over a flame, lithium compounds give off a striking crimson color, but when the metal burns strongly, the flame becomes a brilliant silver. Lithium will ignite and burn in oxygen when exposed to water or water vapors. Lithium is flammable, and it is potentially explosive when exposed to air and especially to water, though less so than the other alkali metals. The lithium-water reaction at normal temperatures is brisk but nonviolent because the hydrogen produced does not ignite on its own. As with all alkali metals, lithium fires are difficult to extinguish, requiring dry powder fire extinguishers (Class D type). Lithium is one of the few metals that react with nitrogen under normal conditions.
Lithium has a diagonal relationship with magnesium, an element of similar atomic and ionic radius. Chemical resemblances between the two metals include the formation of a nitride by reaction with N₂, the formation of an oxide (Li
₂O) and peroxide (Li
₂O
₂) when burnt in O₂, salts with similar solubilities, and thermal instability of the carbonates and nitrides. The metal reacts with hydrogen gas at high temperatures to produce lithium hydride (LiH).
Other known binary compounds include halides (LiF, LiCl, LiBr, LiI), sulfide (Li
₂S), superoxide (LiO
₂), and carbide (Li
₂C
₂). Many other inorganic compounds are known in which lithium combines with anions to form salts: borates, amides, carbonate, nitrate, or borohydride (LiBH
₄). Lithium aluminium hydride (LiAlH
₄) is commonly used as a reducing agent in organic synthesis.
LiHe, a very weakly interacting van der Waals compound, has been detected at very low temperatures.
Unlike other elements in group 1, inorganic compounds of lithium follow the duet rule, rather than the octet rule.
Lithium