Lithium
Atomic Number: 3
Symbol: Li
Atomic Weight: 6.941
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. 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.
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
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
References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952)
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