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Sunday, January 8, 2023

Lithium

 Lithium (from Greek: λίθος, romanizedlithos, lit.'stone') is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid element. Like all alkali metals, lithium is highly reactive and flammable and must be stored in a vacuum, inert atmosphere, or inert liquid such as purified kerosene or mineral oil. When cut, it exhibits a metallic luster, but moist air corrodes it quickly to a dull silvery gray, then black tarnish. It never occurs freely in nature, but only in (usually ionic) compounds, such as pegmatitic minerals, which were once the main source of lithium. Due to its solubility as an ion, it is present in ocean water and is commonly obtained from brines. Lithium metal is isolated electrolytically from a mixture of lithium chloride and potassium chloride.

The nucleus of the lithium atom verges on instability since the two stable lithium isotopes found in nature have among the lowest binding energies per nucleon of all stable nuclides. Because of its relative nuclear instability, lithium is less common in the solar system than 25 of the first 32 chemical elements even though its nuclei are very light: it is an exception to the trend that heavier nuclei are less common.[4] For related reasons, lithium has important uses in nuclear physics. The transmutation of lithium atoms to helium in 1932 was the first fully man-made nuclear reaction, and lithium deuteride serves as a fusion fuel in staged thermonuclear weapons.[5]

Lithium and its compounds have several industrial applications, including heat-resistant glass and ceramicslithium grease lubricants, flux additives for iron, steel, and aluminum production, lithium metal batteries, and lithium-ion batteries. These uses consume more than three-quarters of lithium production.

Lithium is present in biological systems in trace amounts; its functions are uncertain. Lithium salts have proven to be useful as a mood stabilizer and antidepressant in the treatment of mental illnesses such as bipolar disorder.


Lithium, 3Li
Lithium paraffin.jpg
Lithium floating in oil
Lithium
Pronunciation/ˈlɪθiəm/ (LITH-ee-əm)
Appearancesilvery-white
Standard atomic weight Ar°(Li)
  • [6.9386.997]
  • 6.94±0.06 (abridged)[1]
Lithium in the periodic table
HydrogenHelium
LithiumBerylliumBoronCarbonNitrogenOxygenFluorineNeon
SodiumMagnesiumAluminiumSiliconPhosphorusSulfurChlorineArgon
PotassiumCalciumScandiumTitaniumVanadiumChromiumManganeseIronCobaltNickelCopperZincGalliumGermaniumArsenicSeleniumBromineKrypton
RubidiumStrontiumYttriumZirconiumNiobiumMolybdenumTechnetiumRutheniumRhodiumPalladiumSilverCadmiumIndiumTinAntimonyTelluriumIodineXenon
CaesiumBariumLanthanumCeriumPraseodymiumNeodymiumPromethiumSamariumEuropiumGadoliniumTerbiumDysprosiumHolmiumErbiumThuliumYtterbiumLutetiumHafniumTantalumTungstenRheniumOsmiumIridiumPlatinumGoldMercury (element)ThalliumLeadBismuthPoloniumAstatineRadon
FranciumRadiumActiniumThoriumProtactiniumUraniumNeptuniumPlutoniumAmericiumCuriumBerkeliumCaliforniumEinsteiniumFermiumMendeleviumNobeliumLawrenciumRutherfordiumDubniumSeaborgiumBohriumHassiumMeitneriumDarmstadtiumRoentgeniumCoperniciumNihoniumFleroviumMoscoviumLivermoriumTennessineOganesson
H

Li

Na
helium ← lithium → beryllium
Atomic number (Z)3
Groupgroup 1: hydrogen and alkali metals
Periodperiod 2
Block  s-block
Electron configuration[He] 2s1
Electrons per shell2, 1
Physical properties
Phase at STPsolid
Melting point453.65 K ​(180.50 °C, ​356.90 °F) 
Boiling point1603 K ​(1330 °C, ​2426 °F) 
Density (near r.t.)0.534 g/cm3
when liquid (at m.p.)0.512 g/cm3
Critical point3220 K, 67 MPa (extrapolated)
Heat of fusion3.00 kJ/mol
Heat of vaporization136 kJ/mol 
Molar heat capacity24.860 J/(mol·K) 
Vapor pressure
P (Pa)1101001 k10 k100 k
at T (K)797885995114413371610
Atomic properties
Oxidation states0[2]+1 (a strongly basicoxide)
ElectronegativityPauling scale: 0.98 
Ionization energies
  • 1st: 520.2 kJ/mol 
  • 2nd: 7298.1 kJ/mol 
  • 3rd: 11815.0 kJ/mol 
Atomic radiusempirical: 152 pm
Covalent radius128±7 pm 
Van der Waals radius182 pm 
Color lines in a spectral range
Spectral lines of lithium
Other properties
Natural occurrenceprimordial
Crystal structurebody-centered cubic (bcc)
Body-centered cubic crystal structure for lithium
Speed of soundthin rod6000 m/s (at 20 °C) 
Thermal expansion46 µm/(m⋅K) (at 25 °C) 
Thermal conductivity84.8 W/(m⋅K) 
Electrical resistivity92.8 nΩ⋅m (at 20 °C) 
Magnetic orderingparamagnetic 
Molar magnetic susceptibility+14.2×10−6 cm3/mol (298 K)[3]
Young's modulus4.9 GPa 
Shear modulus4.2 GPa 
Bulk modulus11 GPa 
Mohs hardness0.6 
Brinell hardness5 MPa 
CAS Number7439-93-2 
History
DiscoveryJohan August Arfwedson (1817)
First isolationWilliam Thomas Brande (1821)
Main isotopes of lithium
Iso­topeDecay
abun­dancehalf-life(t1/2)modepro­duct
6Li4.85 %stable
7Li95.15 %stable
 Category: Lithium
 | references

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