Basic properties of metallic lithium

Lithium metal

Lithium is a silver-white metal, very light, and the lightest of all metals.It weighs only one-fifth of the same volume of aluminum and one-half of water.

Lithium not only floats on water, but also on kerosene.If an aircraft is made of lithium, two people can lift it.

Lithium has active chemical properties and can react with most non-metals except rare gases under certain conditions.

1、Basic information of lithium metal

CAS No.: 7439-93-2

 Appearance: Silver-white soft metal

 Atomic number: 3

 Atomic weight: 6.941

 Melting point: 180.5℃

 Boiling point: 1342 ℃

 Specific heat capacity: 3.58 kJ/kg·K

2、Properties and distribution of metallic lithium

 1）physical property

Lithium metal is a silver-white light metal with a soft texture and a hardness of 0.6, which is soluble in liquid ammonia.

Because of its small atomic radius, lithium has the smallest compressibility, 

the highest hardness, and the highest melting point compared to other alkali metals.

When the temperature is higher than -117℃, metallic lithium is a typical body-centered cubic structure, 

but when the temperature drops to -201℃, it begins to transform into a face-centered cubic structure. 

The lower the temperature, the greater the degree of transformation, but the transformation is not complete.

Lithium easily fuses with any metal other than iron.

Lithium appears as purple-red in flame reaction.

2）chemical property

Lithium is very active chemically. When placed in water, it will react quickly with water and release hydrogen gas. 

When the temperature reaches above 100℃, lithium will burn in the air, showing a blue flame.

The active nature of lithium allows it to react with most non-metals except for rare gases under certain conditions.

It can also be synthesized with hydrogen and deuterium to form lithium hydride and lithium deuteride, 

which have explosive properties.

Lithium is easy to react with hydrogen at about 500℃ to produce lithium hydride, 

which is the only alkali metal that can generate stable hydrides that are strong enough to melt without decomposing. 

It can combine with oxygen, nitrogen, sulfur, etc., and is the only alkali metal that reacts with nitrogen at room temperature to produce lithium nitride.

3）distribution in nature

The main lithium minerals in nature are spodumene, lepidolite, petalite, and alunite;

The liquid minerals containing lithium mainly include salt lake brine, underground brine, hot springs, etc.

Lithium can also be found in human and animal bodies, soil and mineral water, cocoa powder, tobacco leaves, and seaweed.

3、Application of lithium metal

 Battery industry

Batteries with lithium as the negative electrode have high energy density.

Lithium batteries also have the advantages of light weight, small size, long life, good performance, and low pollution.

Lithium batteries have been widely used in electric vehicles, energy storage batteries, laptops, mobile phones, digital cameras, 

small electronic equipment, aerospace, electromechanical and military communications.

reducing agent

Lithium metal dissolved in a mixed solvent of liquid ammonia and ethanol forms a good reducing agent, 

which can be used to reduce organic compounds containing aromatic rings.Valuable steroids are usually reduced by this method.

The advantage of this method is that the yield is higher, but the disadvantage is that it is more expensive than using sodium reduction,

so it is only used to reduce some expensive compounds.

Aerospace fuel

Lithium and its compounds have the characteristics of high combustion rate, fast speed, wide flame, and large heat generation.

The energy released by 1kg lithium through a thermonuclear reaction is equivalent to the combustion of more than 20,000 tons of high-quality coal.

Therefore, lithium is one of the best metals used as rocket fuel.