Lithium (Li)

Stable isotopes of lithium available from ISOFLEX

Isotope Z(p) N(n) Atomic Mass Natural Abundance Enrichment Level Chemical Form
Li-7 3 4 7.016004 92.50%  ≥99.95%  Hydroxide Monohydrate

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Lithium, named for the Greek word lithos (“stone”), was discovered in 1817 by Johan August Arfvedson during an analysis of petalite ore from the Swedish island of Utö.

A soft, silvery-white metal with a body-centered cubic structure, lithium has a heat capacity about the same as that of water. It ignites in air near its melting point and burns with a crimson-red flame and dense white fumes. It has a dangerous fire and explosion risk when exposed to water, nitrogen, acids or oxidizing agents. It is soluble in liquid ammonia, forming a blue solution.

Lithium has a high electrical conductivity and is used to make high-energy lithium batteries. It can be combined with lead, magnesium, aluminum or other metals for very useful alloys. Its most important application is in preparative chemistry as the starting material to prepare lithium hydride, amide, nitride, alkyls and aryls.

Properties of Lithium

Name Lithium
Symbol Li
Atomic number 3
Atomic weight 6.941
Standard state Solid at 298 °K
CAS Registry ID 7439-93-2
Group in periodic table
Group name Alkali metal
Period in periodic table 2
Block in periodic table s-block
Color Silvery-white
Classification Metallic
Melting point 180.54 °C
Boiling point 1342 °C
Thermal conductivity 84.8 W/(m·K) at 298.2 °K
Electrical resistivity 8.55 µΩ·cm at 0 °C; 12.7 µΩ·cm at 100 ºC
Electronegativity 1.0 
Specific heat 3.57 kJ/kg K
Heat of vaporization 147 kJ·mol-1 at 1342 °C
Heat of fusion 3.10 kJ·mol-1
Density of solid 0.534 g/cm3
Vapor pressure  1 torr at 745 °C and 10 torr at 890 ºC
Oxidation state  +1 
Atomic radius  1.225 Å
Ionic radius  Li+: 0.59 Å (coordination number 4)
Electron configuration  [He]2s1

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