Chemical elements
    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
      Barium Oxide
      Barium Hydroxide
      Barium Peroxide
      Barium Peroxyhydrate
      Barium Tetroxide
      Barium Sulphide
      Barium Hydrosulphide
      Barium Polysulphides
      Barium Hydroxyhydrosulphide
      Barium Oxysulphides
      Barium Sulphite
      Barium Thiosulphate
      Barium Dithionate
      Barium Trithionate
      Barium Tetrathionate
      Barium Pentathionate
      Barium Sulphate
      Acid Barium Sulphates
      Barium Pyrosulphate
      Barium Persulphate
      Barium Selenide
      Barium Selenite
      Barium Selenate
      Acid Barium Selenate
      Barium Telluride
      Barium Tellurite
      Barium Tellurate
      Barium Chromite
      Barium Chromate
      Barium Dichromate
      Barium Potassium Trichromate
      Barium Chlorochromate
      Barium Perchromate
      Barium Molybdate
      Barium Permolybdate
      Barium Tungstate
      Barium Uranate
      Barium Diuranate
      Barium Peruranate
      Barium Nitride
      Barium Azide
      Barium Hexammoniate
      Barium Ammonium
      Barium Amide
      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 Carbonate, BaCO3

Barium Carbonate, BaCO3, occurs naturally as the mineral witherite, in orthorhombic crystals isomorphous with aragonite and strontianite. A mineral consisting of mixed crystals of barium and calcium carbonates, barytocalcite, is also found.

Barium carbonate may be readily obtained by precipitation from a solution of a barium salt by an alkali carbonate, or by the action of carbon dioxide on barium hydroxide solution. It can be formed by the union of carbon dioxide with anhydrous barium oxide if the temperature is raised to about 550° C. It may also be obtained in crystalline form by fusion of barium chloride with sodium carbonate and extraction with water, or by fusion of the precipitated carbonate with sodium chloride, or by heating with ammonium nitrate or carbonate solution in a sealed tube at 150°-180° C.

Commercially it is prepared from the sulphate by reduction to the sulphide and treatment of a hot solution of the latter with carbon dioxide.

The density of witherite is 4.3 – 4.5, and of the precipitated carbonate 4.22 – 4.37. The specific heat is 0.14483.

Barium carbonate is more difficult to decompose than either calcium or strontium carbonate. The dissociation pressure only reaches one atmosphere at 1350° C., when, according to Finkelstein, a basic carbonate, BaO.BaCO3, is formed. This basic carbonate melts below 950° C. It can be formed by prolonged heating at 1120° C., and it dissolves barium oxide and, at higher temperatures, barium carbonate. By extrapolation the temperature of decomposition of the basic carbonate is found to be 1454° C.

Le Chatelier gave the temperature of fusion in an open vessel as 795° C., but this low value was no doubt due to the formation of barium oxide. It only partially fuses when heated at 1380° C. in a current of carbon dioxide. The melting-point under a pressure of carbon dioxide appears to be about 1740° C., when determined by extrapolation from the fusion curve of mixtures of calcium and barium carbonates. There are two transition points, one at 811° C., from witherite or γ-carbonate to carbonate, a hexagonal form, and the other at 982° C., from β- to α-barium carbonate, which is regular in crystalline form.

If carbon dioxide be passed through a methyl alcoholic solution of barium oxide, barium carbonate separates in a gelatinous form and behaves as a reversible colloid, giving a clear solution which is practically a non-conductor of electricity so long as it is not completely freed from methyl alcohol.

By the action of sodium on barium carbonate, carbon is liberated and the oxide formed. Carbon also separates when a solid mixture of chloride and carbonate is electrolysed at 550°-600° C.

The solubility of barium carbonate in water is very small, but greater than that of the other alkaline earth carbonates. The results obtained by different investigators are rather variable, as the solubility depends on the pressure of carbon dioxide, and there are probably present in solution hydroxyl ions due to the hydrolysis of the salt, and hydrogen carbonate ions owing to the formation of bicarbonate. By electrical conductivity determinations the solubility was found to be 24 mgm., or 1.22×10-4 grm.-mol. per litre at 18° C. Weissenberger determined the solubility in the presence of a small quantity of caustic soda to suppress the hydrolysis, and observed a minimum solubility at a hydroxyl-ion concentration of 1.25×10-5 grm.-ion per litre. With a higher concentration the hydroxide is formed, and therefore the solubility is apparently increased. The true values of the solubility were considered to be as follows: -

Temperature °C141823273238
Gram-molecules BaCO3 per litre×1044.324.574.895.225.696.27

The solubility is increased by the presence of ammonium chloride, probably due to the formation of a double chloride in solution, and also by potassium and sodium chlorides and sulphates, magnesium and zinc sulphates, and by calcium nitrate and chloride, all of which probably bring about partial decomposition of the carbonate.

McCoy and Smith, working under pressures of 0.2 - 30 atmospheres of carbon dioxide, found as the value of the solubility product [Ba••]×[CO3'], 8.1×10-9 at 25° C. The maximum solubility was reached at 22 atmospheres and was 7.3 grm. of barium bicarbonate per litre at 25° C. Above this pressure, therefore, it should be possible to separate the solid bicarbonate. This compound may apparently be precipitated from ice-cold solutions of barium chloride by ammonium bicarbonate, preferably with the addition of gelatine to stabilise it, its composition being approximately represented by the formula BaCO3.1.5H2CO3. A compound of composition 2BaO.3CO2 was described by Boussingault as formed by the action of sodium sesqui- carbonate on barium chloride.

A double salt with potassium carbonate, BaCO3.K2CO3, is formed by precipitation from saturated solutions of barium chloride and potassium carbonate at room temperature. The same compound, as well as a similar sodium salt, may also be formed by fusion.

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