Lithium Facts

Chemical & Physical Properties

Lithium
Atomic Number: 3
Symbol: Li
Atomic Weight: [6.938; 6.997]
Reference: IUPAC 2009
Discovery: 1817, Arfvedson (Sweden)
Electron Configuration: [He]2s¹
Word Origin Greek: lithos, stone
Properties: Lithium has a melting point of 180.54°C, boiling point of 1342°C, specific gravity of 0.534 (20°C), and valence of 1. It is the lightest of the metals, with a density approximately half that of water. Under ordinary conditions, lithium is the least dense of the solid elements. It has the highest specific heat of any solid element. Metallic lithium is silvery in appearance. It reacts with water, but not as vigorously as does sodium. Lithium imparts a crimson color to flame, although the metal itself burns a bright white. Lithium is corrosive and requires special handling. Elemental lithium is extremely flammable.

Uses: Lithium is used in heat transfer applications. It is used as an alloying agent, in synthesizing organic compounds, and is added to glasses and ceramics. Its high electrochemical potential makes it useful for battery anodes. Lithium chloride and lithium bromide are highly hygroscopic, so are used as drying agents. Lithium stearate is used as a high-temperature lubricant. Lithium has medical applications, as well.
Sources: Lithium does not occur free in nature. It is found in small amounts in practically all igneous rocks and in the waters of mineral springs. The minerals that contain lithium include lepidolite, petalite, amblygonite, and spodumene. Lithium metal is produced electrolytically from the fused chloride.
Element Classification: Alkali Metal
Density (g/cc): 0.534
Appearance: soft, silvery-white metal
Isotopes: 8 isotopes [Li-4 to Li-11]. Li-6 (7.59% abundance) and Li-7 (92.41% abundance) are both stable.
Atomic Radius (pm): 155
Atomic Volume (cc/mol): 13.1
Covalent Radius (pm): 163
Ionic Radius: 68 (+1e)
Specific Heat (@20°C J/g mol): 3.489
Fusion Heat (kJ/mol): 2.89
Evaporation Heat (kJ/mol): 148
Debye Temperature (°K): 400.00
Pauling Negativity Number: 0.98
First Ionizing Energy (kJ/mol): 519.9
Oxidation States: 1
Lattice Structure: Body-Centered Cubic
Lattice Constant (Å): 3.490
Magnetic Ordering: paramagnetic
Electrical Resistivity (20°C): 92.8 nΩ·m
Thermal Conductivity (300 K): 84.8 W·m−1·K−1
Thermal Expansion (25°C): 46 µm·m−1·K−1
Speed of Sound (thin rod) (20°C): 6000 m/s
Young's Modulus: 4.9 GPa
Shear Modulus: 4.2 GPa
Bulk Modulus: 11 GPa
Mohs Hardness: 0.6
CAS Registry Number: 7439-93-2
Lithium Trivia:

• Lithium is used extensively in rechargeable battery technology.
• Lithium is the only alkali metal that reacts with nitrogen.
• Lithium burns red in a flame test.
• Lithium was first discovered in the mineral petalite (LiAlSi₄O₁₀).
• Lithium is used to create the hydrogen isotope tritium through bombardment of neutrons.

References: Los Alamos National Laboratory (2001), IUPAC 2009, Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952)