Chemical elements
  Barium
    Isotopes
    Energy
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    Physical Properties
    Chemical Properties
      Barium Hydride
      Barium Subfluoride
      Barium Fluoride
      Acid Barium Fluoride
      Barium Subchloride
      Barium Chloride
      Barium Bromide
      Barium Perbromides
      Barium Iodide
      Barium Periodides
      Barium Mixed Halides
      Barium Mixed Perhalides
      Barium Oxychloride
      Barium Hypochlorite
      Barium Chlorite
      Barium Chlorate
      Barium Perchlorate
      Barium Oxybromide
      Barium Hypobromite
      Barium Bromate
      Barium Perbromate
      Barium Oxyiodide
      Barium Iodate
      Barium Periodate
      Barium Manganites
      Barium Manganate
      Barium Permanganate
      Barium Suboxide
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      Barium Peroxyhydrate
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      Acid Barium Sulphates
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      Barium Persulphate
      Barium Selenide
      Barium Selenite
      Barium Selenate
      Acid Barium Selenate
      Barium Telluride
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      Barium Chromite
      Barium Chromate
      Barium Dichromate
      Barium Potassium Trichromate
      Barium Chlorochromate
      Barium Perchromate
      Barium Molybdate
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      Barium Tungstate
      Barium Uranate
      Barium Diuranate
      Barium Peruranate
      Barium Nitride
      Barium Azide
      Barium Hexammoniate
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      Barium Amide
      Baramide
      Barium Amidosulphonate
      Barium Imide
      Barium Imidosulphonate
      Barium Hyponitrite
      Barium Nitroxysulphite
      Barium Nitrososulphate
      Barium Nitrohydroxylaminate
      Barium Nitrite
      Barium Nitrate
      Barium Phosphide
      Barium Dihydrohypophosphite
      Barium Hydrophosphite
      Barium Hypophosphate
      Barium Orthophosphates
      Barium Pyrophosphate
      Barium Metaphosphate
      Basic Barium Phosphates
      Barium Thiophosphites
      Barium Thiophosphates
      Barium Selenophosphates
      Barium Azophosphates
      Barium Phosphimates
      Barium Arsenide
      Barium Orthoarsenite
      Barium Pyroarsenite
      Barium Orthoarsenates
      Barium Pyroarsenate
      Barium Thioarsenites
      Barium Thioarsenates
      Barium Sodium Selenoxyarsenate
      Barium Metantimonate
      Barium Thioantimonites
      Barium Chloroantimonite
      Barium Orthothioantimonate
      Barium Hypovanadate
      Barium Vanadates
      Barium Metapervanadate
      Barium Niobate
      Barium Tantalate
      Barium Pertantalate
      Barium Carbide
      Barium Carbonyl
      Barium Formate
      Barium Acetate
      Barium Oxalate
      Barium Carbonate
      Barium Thiocarbonate
      Barium Percarbonate
      Barium Cyanide
      Barium Cyanamide
      Barium Cyanate
      Barium Cyanurate
      Barium Thiocyanate
      Barium Selenocyanate
      Barium Silicide
      Barium Silicates
      Barium Fluosilicate
      Barium Stannate
      Barium Orthoplumbate
      Barium Titanate
      Barium Peroxide Pertitanate
      Barium Pertitanate
      Barium Fluoroxytitanate
      Barium Zirconate
      Barium Boride
      Barium Borates
      Barium Fluorborate
      Barium Perborate
      Barium Aluminates
      Barium Ferrite
      Barium Ferrate
      Barium Gobaltite
      Barium Dinickelite
      Barium Platinate
    Detection of Barrium
    PDB 1djh-3iqp
    PDB 3iqr-4e7y

Barium Iodide, BaI2






Barium Iodide, BaI2 may be obtained by the neutralisation of hydriodic acid by barium carbonate, hydroxide, or sulphide. Instead of hydriodic acid, iodine and a reducing agent, for example iron or barium sulphite, may advantageously be employed. By the action of iodine on barium hydroxide, barium iodide in solution and practically insoluble barium iodate are formed, and can be separated by filtration. Instead of removing barium iodate it may be reduced to barium iodide by sulphuretted hydrogen. Barium iodide is also formed by the action of iodine on barium peroxide in the presence of water. The anhydrous salt is obtained by evaporating to dryness and heating in a current of gaseous hydriodic acid. It is a white, deliquescent compound of density 5.150 at 25° C. and melting-point 740° C. The heat of formation is 149.9 Cal., and the heat of solution 10.3 Cal.

Barium iodide is very readily soluble in water, and the following values have been obtained: -

Temperature, °C-22-9-5153240678796113140165
Grams BaI2 per 100 grams solution.58.560.060.966.068.369.871.972.172.773.673.774.1


The solubility is reduced by the presence of salts with a common ion. Barium iodide is readily soluble in alcohol.

A solution of pure barium iodide has a neutral reaction. When exposed to air and sunlight it soon becomes yellow and deposits barium carbonate.

Barium iodide is stable in dry air at ordinary temperatures, but when heated in air it ultimately gives up all its iodine and forms the oxide.

It is sometimes used for therapeutic purposes.


Hydrates of Barium Iodide

There are apparently several hydrates, but they are difficult to identify on account of their deliquescent nature. The salt crystallising out at ordinary temperatures has been described as a heptahydrate, BaI2.7H2O, but, according to Mugge, commercial barium iodide, in large hexagonal prisms melting in the water of crystallisation at 25.7° C., is a hexahydrate, isomorphous with strontium chloride hexahydrate. By evaporation of concentrated solutions Lescoeur obtained a hexahydrate.

There is also a very hygroscopic dihydrate which is rapidly coloured reddish brown in the air owing to the liberation of iodine. It is isomorphous with barium bromide dihydrate, and is apparently the stable form in contact with saturated solutions at 85° C. At 125° C. the higher hydrates are converted into the monohydrate, which begins to lose water and forms the anhydrous salt at 150° C.

The heat of solution of the heptahydrate is –6.850 Cal.

Addition Compounds of Barium Iodide

Barium iodide forms addition compounds with ammonia containing 1, 2, 4, and 6 molecules of the latter respectively. The compound, BaI2.6NH3, has a dissociation pressure of 50 mm. of mercury at 20° C., and the heat of formation from the iodide and ammonia is 10.80 Cal.

Double Salts of Barium Iodide

Barium iodide forms a number of double salts: BaI2.ZnI2.4H2O, BaI2.2ZnI2, BaI2.HgI2, BaI2.2HgI2, BaI2.3HgI2, BaI2.5HgI2.8H2O, 2BaI2.3HgI2, 2BaI2.3HgI2.16H2O, 3BaI2.5HgI2.2IH2O, BaI2.HgI2.5H2O, BaI2.2Hg(CN)2.4H2O, BaI2.2PbI2.7H2O, 2BaI2.SbI3.18H2O.
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