Lithium:Chemistry,Reactions,Uses
Lithium is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid element. 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.
Chemistry
Lithium is a malleable, soft silvery metal and the first element belonging to the alkali metals. It is small and the lightest among all metals. Its chemistry and that of the rest of the alkali metals is attributed mostly to the ease of involving the ns1 electron in bonding, coupled with the difficulty of removing the second electron from the inner orbitals. As such, lithium as with other alkali metals, react vigorously with water.Lithium's interaction with water is not as explosive and violent as the other alkali metals. This reaction forms hydroxides and hydrogen gas:
Li(s)＋H2O(1)→LiOH(aq)+H (g)
Reactions
Lithium is flammable and burns with a striking crimson flame. When ignited sufficiently well, it gives a brilliant silver flame. The resulting products are mainly lithium oxide (Li2O) and some lithium peroxide (Li2O2), both white powders.
Lithium reacts directly with hydrogen especially at temperatures above 600C to form lithium hydride (LiH).
4Li(s)+O(g)→2Li2O(s)
2Li(s)+O(g)→2Li2zO2(s)
2Li(s)+H2(g)→2LiH(s)
Lithium metal reacts with all the halogens to form lithium halides. So, it reacts with fluorine, F2, chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively lithium fluoride, LiF, lithium chloride, LiCl, lithium bromide, LiBr, and lithium iodide, LiI.
2Li(s)+X2(g)→ 2LiX(s) where X =F,Cl，Br，I
Lithium reacts with acids in a complex manner since the acid solutions contain water, which was shown to vigorously react with lithium forming lithium hydroxide (LiOH).
2Li(s)+H2SO4(aq)→2Li2SO4(aq)+ H2(g)
Uses
The most important application of Li is in rechargeable batteries for mobile phones, laptops, digital cameras, and electric vehicles. Lithium is also used in some nonrechargeable batteries in applications such as heart pacemakers, toys, watches, and clocks. Because of its low atomic mass, it has a high charge- and power-to-weight ratio.
A typical lithium-ion battery can generate approximately 3 volts per cell, compared with 2.1 volts for lead-acid and 1.5 volts for zinc-carbon. Lithium-ion batteries, which are rechargeable and have a high-energy density, differ from lithium batteries, which are disposable (primary) batteries with lithium or its compounds as the anode. Other rechargeable batteries that use lithium include the lithium-ion polymer battery, lithium iron phosphate battery, and the nanowire battery. Lithium is utilized in alloys with aluminum and magnesium, improving their strength and making them lighter.
