What Is Lithium Bromide?

Phil Riddel

Lithium bromide (LiBr), also known as lithium monobromide, is a compound of the elements lithium and bromine, having one atom of lithium bonded to one atom of bromine. It is an ionic compound, meaning that the lithium atom “gives” one electron to the bromine atom, with the result that the lithium atom becomes positively charged and the bromine atom negatively charged; the atoms are then bonded together by electrostatic attraction. Ionic bonding is a common feature of simple metal/non-metal compounds. Lithium is a metal belonging to a group of elements known as the alkali metals because they react with water to produce strong alkalis. Bromine belongs to a group of reactive non-metallic elements known as the halogens, which also include fluorine, chlorine and iodine.

An industrial application of lithium bromide is in air conditioning systems.
An industrial application of lithium bromide is in air conditioning systems.

The compound can also be described as a salt, that is, a substance that can be made by the reaction of a base and an acid — in this case, lithium hydroxide (LiOH) and hydrobromic acid (HBr): LiOH + HBr -> LiBr + H2O. Common salt, or sodium chloride, is another example. Normally, however, lithium bromide is manufactured by reacting hydrobromic acid with lithium carbonate. Lithium bromide is very soluble in water and forms hydrates, which are compounds that include water. It also is extremely hygroscopic, which means that it absorbs moisture from the air, and because of this, it is widely used as a desiccant or drying agent in dehumidifiers, industrial drying systems and air conditioning systems.

Lithium compounds are frequently used to treat patients who have bipolar disorder.
Lithium compounds are frequently used to treat patients who have bipolar disorder.

The biggest commercial and industrial use of lithium bromide is in refrigeration units where water is used as a coolant; these are suitable for applications where freezing is not required, such as chillers and air conditioning systems. Cooling is achieved by evaporation, a process that absorbs heat from the surroundings, just like the way sweating keeps the body cool. To maintain the cooling effect, the water that has evaporated must be recovered from the resulting moist air, and this is achieved by spraying it with a strong solution of lithium bromide that absorbs the water vapor, leaving a more dilute solution. This solution is heated in a boiler to drive off excess water, creating a stronger solution; both the water, converted back to liquid in a condenser, and the strong lithium bromide solution are recycled through the system.

Lithium compounds affect central nervous system (CNS) functions and have been used to treat certain mental conditions, especially bipolar disorder. In modern times, lithium carbonate is normally prescribed, but lithium bromide has been used in the past for the treatment of epilepsy. Ingestion of lithium compounds can produce serious toxic effects because of their action on the CNS.

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Discussion Comments


Lithium is pretty much everywhere. Trace amounts can be found in all life on Earth.

Lithium is a highly reactive element and so it isn't found pure in nature. You have to extract it from other elements if you want a pure form.

Just because it is consistently everywhere though, doesn't mean it's common. It is all over the place, but it isn't found in large amounts. That is probably a good thing because it is very corrosive. It even needs to be handled with gloves to not burn skin.

Lithium may be more help than just for mental disorder. It is still being researched for other possible medicinal uses like headaches. There are some issues that may arise from using lithium, so much more research is needed.

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