Lithium and its Properties

Lithium 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.Lithium, like all alkali metals,is highly reactive and flammable and must be stored under vacuum,in an inert atmosphere,or in an inert liquid such as refined kerosene or mineral oil.When cut, it takes on a metallic sheen, but moist air quickly corrodes it to a dull silvery gray and then black.It never occurs freely in nature,but only in (usually ionic) compounds, such as the pegmatite mineral that was once a major source of lithium.Due to its solubility as an ion, it is found in seawater and is commonly obtained from brines.

Lithium metal is electrolytically separated from a mixture of lithium chloride and potassium chloride.Lithium nuclei are close to unstable because the two stable lithium isotopes found in nature have the lowest binding energies per nucleon of all stable nuclides.Due to its relative nuclear instability, lithium is less common in the solar system than 25 of the top 32 chemical elements,despite its very light nuclei:it is an exception to the trend that heavier nuclei are less common.

Lithium has important uses in nuclear physics for related reasons.The conversion of lithium atoms to helium in 1932 was the first fully man-made nuclear reaction,while lithium deuteride was used as fusion fuel in staged thermonuclear weapons.Lithium and its compounds have a variety of industrial applications, including heat-resistant glass and ceramics,lithium 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 occurs in trace amounts in biological systems; its function is uncertain.Lithium has been shown to be useful as a mood stabilizer and antidepressant in the treatment of mental disorders such as bipolar disorder.

Lithium Properties

Atoms and Physics

Alkali metals are also known as lithium group, named after their main elements.Lithium, like the other alkali metals (sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr)), possesses a valence electron that is easily given up to form a cation.Because of this,lithium is a good conductor of heat and electricity and a highly reactive element, although it is the least reactive of the alkali metals.Lithium's low reactivity is due to the proximity of its valence electrons to its nucleus (the remaining two electrons are in the 1s orbital, which are much lower in energy and do not participate in chemical bonds).Molten lithium is significantly more active than its solid-state form.Lithium metal is so soft that it can be cut with a knife.When cut, it is silvery white, rapidly turning gray as it oxidizes to lithium oxide.It has a melting point of 180.50 °C (453.65 K; 356.90 °F)[9] and a boiling point of 1,342 °C (1,615 K; 2,448 °F)[9], the highest of all alkali metals, while its Density of 0.534 g/cm3 minimum.

Lithium has a very low density (0.534 g/cm3), comparable to pine wood.It is the least dense of all elements that are solid at room temperature; the next lightest solid element (potassium, 0.862 g/cm3) is more than 60% denser. As a solid, it is less dense than any other liquid element, with the exception of helium and hydrogen, and is only two-thirds as dense as liquid nitrogen (0.808 g/cm3).Lithium floats on the lightest hydrocarbon oils and is one of only three metals that float on water, the other two being sodium and potassium.

Lithium has a thermal expansion coefficient twice that of aluminum and almost four times that of iron.Lithium is superconducting below 400 μK at standard pressure and at higher temperatures (over 9 K) and very high pressures (>20 GPa) [14] at below 70 K Lithium, like sodium, undergoes a diffusionless phase transition at high temperature. At 4.2 K it has a rhombohedral crystal system (with nine-layer repeat spacing); at higher temperatures it transforms into a face-centered cubic and then into a body-centered cubic.At liquid helium temperatures (4 K), rhombohedral structures are prevalent.have identified various allotropic forms of lithium at high pressure.Lithium has a specific heat capacity by mass of 3.58 kilojoules per kilogram Kelvin, the highest of any solid.Because of this, lithium metal is commonly used as a coolant for heat transfer applications.