Chemical elements
    Physical Properties
    Chemical Properties
      Strontium Hydride
      Strontium Fluoride
      Strontium Chloride
      Strontium Perchloride
      Strontium Bromide
      Strontium Perbromide
      Strontium Iodide
      Strontium Periodides
      Mixed Halides
      Strontium Oxychloride
      Strontium Hypochlorite
      Strontium Chlorite
      Strontium Chlorate
      Strontium Perchlorate
      Strontium Oxybromide
      Strontium Bromate
      Strontium Oxyiodide
      Strontium Iodate
      Strontium Periodate
      Strontium Manganite
      Strontium Manganate
      Strontium Permanganate
      Strontium Suboxide
      Strontium Oxide
      Strontium Hydroxide
      Strontium Peroxide
      Strontium Diperoxyhydrate
      Strontium Hydride
      Strontium Hydrosulphide
      Strontium Polysulphides
      Strontium Oxysulphide
      Strontium Thiosulphate
      Strontium Hyposulphite
      Strontium Sulphite
      Strontium Dithionate
      Strontium Tetrathionate
      Strontium Sulphate
      Acid Strontium Sulphate
      Strontium Pyrosulphate
      Strontium Selenide
      Strontium Selenite
      Strontium Selenate
      Strontium Telluride
      Strontium Tellurite
      Strontium Tellurate
      Strontium Chromate
      Strontium Dichromate
      Strontium Trichromate
      Strontium Chlorochromate
      Strontium Molybdate
      Complex Strontium Molybdates
      Strontium Tungstate
      Strontium Uranate
      Strontium Nitride
      Strontium Azide
      Strontium Ammonium
      Strontium Hexammoniate
      Strontium Amide
      Strontium Imide
      Strontium Imidosulphonate
      Strontium Hyponitrite
      Strontium Nitrohydroxylaminate
      Strontium Nitrite
      Strontium Nitrate
      Strontium Phosphide
      Strontium Dihydrohypophosphite
      Strontium Hydrophosphite
      Strontium Dihydrophosphite
      Strontium Orthophosphates
      Strontium Pyrophosphate
      Strontium Metaphosphate
      Basic Strontium Phosphate
      Strontium Arsenide
      Strontium Orthoarsenites
      Strontium Pyroarsenite
      Strontium Metarsenite
      Strontium Orthoarsenates
      Strontium Pyroarsenate
      Strontium Thioarsenites
      Strontium Thio-oxyarsenates
      Strontium Thioantimonite
      Strontium Antimonate
      Strontium Orthovanadate
      Strontium Metavanadate
      Strontium Pervanadate
      Strontium Carbide
      Strontium Carbonyl
      Strontium Formate
      Strontium Acetate
      Strontium Oxalate
      Strontium Carbonate
      Strontium Trithiocarbonate
      Strontium Perthiocarbonate
      Strontium Cyanide
      Strontium Cyanamide
      Strontium Thiocyanate
      Strontium Silicide
      Strontium Silicate
      Strontium Fluosilicate
      Strontium Stannate
      Strontium Orthoplumbate
      Strontium Titanate
      Strontium Zirconate
      Strontium Boride
      Strontium Borates
      Strontium Aluminates
      Strontium Ferrate
    PDB 1cs7-2spt
    PDB 2woh-4ds7

Strontium Chloride, SrCl2

Strontium Chloride, SrCl2, was first prepared by Crawford in 1790. It may be obtained by direct combination of its elements, by the action of chlorine or hydrochloric acid on strontium oxide at high temperatures, or by neutralising strontium hydroxide, carbonate, or sulphide with hydrochloric acid solution, evaporating and fusing the residue in a current of hydrochloric acid gas. On a large scale it is prepared by the action of calcium chloride on strontium carbonate. It may be obtained in a gelatinous form by precipitation under suitable conditions.

The heat of formation of strontium chloride from its elements is 195.66 Cal. The melting-point is 874° C. The density is 2.95 – 3.05 at ordinary temperatures, and at the melting-point 2.77. The specific heat is 0.1199. The following values have been found for the specific electrical conductivity of the fused salt: -

Temperature, ° C.873900950100010501100
Ohms-1 per c.c.1.921.982.142.292.432.56

The decomposition potential of strontium chloride at 880° C. is 3.4 volts, and of the salt dissolved in potassium chloride and calcium fluoride to bring down the temperature of fusion, 3.0 volts at 615° C., whilst the temperature coefficient is 0.715×10-3.

Strontium chloride is decomposed by superheated steam, giving hydrochloric acid, and when heated in contact with air it loses chlorine, forming the oxide. Bromine partially replaces the chlorine at high temperatures.

Anhydrous strontium chloride is very hygroscopic, but not quite to the same extent as calcium chloride. It dissolves in water with the evolution of 11.14 Cal. of heat per gram-molecule.

The following values have been found for the solubilities at different temperatures: -

Temperature, ° C. -17-11-5-127183555647598105118132153175215250
Grams SrCl2 per grams solution26.528.629.330.831.331.733.737.843.846.446.549.650.752.052.555.760.564.167.3

There seems to have been some doubt as to the nature of the solid phase in the neighbourhood of 75° C., so that probably equilibrium was not reached.

Harkins found that hydrochloric acid diminished the solubility of strontium chloride from 5160 milli-equivalents per litre at 0° to 425 milli-equivalents in a solution containing 5275 milli-equivalents of hydrochloric acid per litre.

The solubility in alcohol is not very great.

The boiling-points of concentrated aqueous solutions have been studied by Gerlach. A solution containing 487.5 grm. of the anhydrous chloride in 100 grm. of water has a boiling-point of 117° C. Freezing-point determinations of both dilute and concentrated solutions have been made. Aqueous solutions have also been studied from the point of view of surface tension, compressibility, viscosity, electrical conductivity, density, and vapour pressure. The equilibria between strontium and potassium amalgams of different concentrations and solutions of strontium and potassium chlorides have been investigated.

The Hydrates of Strontium Chloride

Vapour pressure measurements indicate only a hexa- and a di-hydrate, although Etard suggested the possibility of a mono-hydrate.

Strontium Chloride Hexahydrate, SrCl2,6H2O

Strontium Chloride Hexahydrate, SrCl2.6H2O, crystallises from solutions at ordinary temperatures. It forms colourless hexagonal needles isomorphous with calcium chloride hexahydrate. The density is 1.954. The heat of formation of the hexahydrate from the anhydrous salt and water is 18.64 Cal., and the heat of solution is -7.50 Cal. The vapour pressure at 25° C. is 8.37 mm.

The hexahydrate is very soluble in methyl alcohol, much more so than in ethyl alcohol.

The temperature of transition to the dihydrate has been carefully determined by Richards and Yngve as 61.34° C. It is lowered by contact of the salt with a solution containing hydrochloric acid; at 25° C. the two hydrates are in equilibrium with a solution containing 2.11 per cent, of strontium chloride and 27.14 per cent, of acid.

Strontium Chloride Dihydrate, SrCl2,2H2O

Strontium Chloride Dihydrate, SrCl2.2H2O, crystallises from solutions above the transition point in slightly deliquescent prisms. It may be obtained at ordinary temperatures from a solution of strontium chloride in concentrated hydrochloric acid, or by passing hydrochloric acid gas into a saturated solution of strontium chloride. The heat of hydration of anhydrous strontium chloride to the dihydrate is 9.06 Cal.

There appears to be no record of the temperature of transition from the dihydrate to the anhydrous form, but it is not below 130° C.

Addition Compounds

Anhydrous strontium chloride absorbs dry ammonia, forming a voluminous white powder of approximate composition, SrCl2.8NH3. The dissociation pressure is 100 mm. At 3.5° C. There is also a monammoniate, SrCl2.NH3, which has a vapour pressure of 100 mm. At 45.5° C. The heat of formation of the octammoniate is 9.98 Cal., and of the monammoniate 10.5 Cal. at 0° C., 12.5 at 78° C., and 13.4 at 108° C. Addition compounds are also formed with hydroxylamine, 2SrCl2.5NH2OH.2H2O and 2SrCl2.9NH2OH.3HCl.H2O, and one with glycine, SrCl2.2NH2CH2COOH.3H2O.

Double Salts of Strontium Chloride

On the following page is a list of the double salts formed by strontium chloride.

It has been suggested that double salts in solution may contain the ion SrCl42-.

Strontium chloride forms mixed crystals or solid solutions, but not compounds with calcium chloride, barium chloride, and lead chloride.
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