Chemical elements
    Physical Properties
    Chemical Properties
      Lithium hydride
      Lithium chloride
      Lithium bromide
      Lithium iodide
      Lithium iodide tetrachloride
      Lithium hypochlorite
      Lithium chlorate
      Lithium perchlorate
      Lithium bromate
      Lithium iodate
      Lithium periodates
      Lithium monoxide
      Lithium peroxide
      Lithium hydroxide
      Lithium monosulphide
      Lithium polysulphides
      Lithium sulphite
      Lithium sulphate
      Lithium persulphate
      Lithium thiosulphate
      Lithium dithionate
      Lithium selenide
      Lithium selenite
      Lithium selenate
      Lithium chromate
      Lithium permanganate
      Lithium molybdates
      Lithium nitride
      Lithium hydrazoate
      Lithium nitrite
      Lithium nitrate
      Lithium phosphide
      Lithium orthophosphate
      Lithium pyrophosphate
      Lithium metaphosphate
      Lithium arsenide
      Lithium meta-arsenite
      Lithium arsenate
      Lithium antimonide
      Lithium antimonate
      Lithium carbide
      Lithium carbonate
      Lithium percarbonate
      Lithium cyanide
      Lithium thiocyanate
      Lithium silicide
      Lithium silicates
      Lithium borates

Lithium bromide, LiBr

The anhydrous bromide is obtained by dissolving the carbonate in aqueous hydrobromic acid, and evaporating the solution to dryness in a current of gaseous hydrogen bromide. Bogorodsky has isolated three hydrates from the aqueous solution, each forming very deliquescent crystals. At very low temperatures the trihydrate, LiBr,3H2O, is deposited; at 4° C. it is changed to the dihydrate, LiBr,2H2O; at 44° C. this substance yields the monohydrate, LiBr,H2O; above 159° C. the anhydrous salt is deposited. A crystalline form is also described containing 1-1½H2O. For the melting-point of anhydrous lithium bromide Carnelley gives 547° C., and Wartenberg and Schulz give 549° C.; but Ramsay and Eumorfopoulos found the much lower value 442° C. At its melting-point it evolves bromine freely. The boiling-point is 1310° C., and the vapour-pressure in atmospheres corresponds with the expression

log p = -35600/4.57T+5.109.

The values obtained by Kremers for the solubility in water are given in the table:

Temperature, °C010203040506080100
Grams LiBr in 100 g. H2O143161177190202214224245266

Other investigations of the properties of aqueous solutions have been made by various experimenters. Bonnefoi has prepared complex compounds of lithium bromide and ammonia analogous to those formed by the chloride.

Although the heat of formation of lithium bromide in aqueous solution has not been determined, analogy with the corresponding sodium compounds indicates that it should be similar to that of lithium chloride -

LiOH,Aq.+HBr,Aq. =LiBr,Aq. +13.85 Cal.

By combining this value with the heat of solution of lithium in water (53.2 Cal.) and with the heat of formation of hydrobromic acid in dilute solution (28.38 Cal.), there results the equation

[Li]+Br+Aq.=LiBr,Aq.+95.43 Cal.

Subtraction of the heat of solution of the anhydrous bromide (11.35 Cal.) gives the heat of formation of the salt from its elements in accordance with the equation

[Li]+Br=[LiBr]+84.l Cal.

Like the chloride, lithium bromide yields double compounds with alcohols.

Lithium bromide forms double salts with other metallic bromides, such as those of copper and tin.

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