Barium chloride

“ A. N. Guntz (Comptes rendus, 1901, 133, p. 872) electrolyses a saturated solution of barium chloride using a mercury cathode and obtains a 3% barium amalgam; this amalgam is transferred to an iron boat in a wide porcelain tube and the tube slowly heated electrically, a good yield of pure barium being obtained at about 1000° C. The metal when freshly cut possesses a silver white lustre, is a little harder than lead, and is extremely easily oxidized on exposure; it is soluble in liquid ammonia, and readily attacks both water and alcohol. ”

“ Experience has shown that water which contains appreciable quantities of organic matter does not give a pure white product. The presence of sulphate of lime in the water, which precipitates barium sulphate, need not be regarded, because the barium sulphate is so finely divided that it remains suspended in the liquid, and is carried down on precipitation of the enamel white by sulphuric acid. Carbonate of lime in the water causes the separation of barium carbonate; this may be avoided by slightly acidifying the barium chloride solution, thus converting the calcium carbonate into chloride. ”

“ Commercial chloride of barium thus purified is probably the most convenient source of the other compounds of barium when required pure. Thus pure carbonate of baryta may be prepared from it by precipitation with carbonate of ammonia, or with carbonate of soda, which is free from silica, sulphuric acid and phosphoric acid.15
14 It may be that leaden pans are used for the evaporation or cry­stal­li­za­tion of the commercial chloride of barium, which would sufficiently account for the presence of lead in the product. ”

“ Artificially-prepared barium sulphate is used as a pigment, Permanent White, also in the paper industry and in vulcanizing rubber. Other salts of barium of importance are barium chloride, barium nitrate, and barium carbonate, used in pyrotechny and in glass manufacture.
Barytes (American Barite) , a rhombic mineral consisting of barium sulphate (specific gravity 4.5) occurring in veins and extensive masses as a subsequent deposit in various rocks. Colourless to brownish, the colourless massive examples being in great demand as a substitute for white lead in paint and for other purposes. ”

“ The dry chloride is spontaneously luminous: its Becquerel radiation is similar to that of barium-radium chloride. M. Debierne has prepared an active barium chloride 1000 times as active as uranium. This barium, however, had not acquired all the characteristics of radium, for it showed none of the strongest radium lines in the spectroscope. Further, its activity diminished on standing, and after three weeks it had become one-third of its original value.
There is a wide field for research upon the radio-activity induced in substances in solution with active bodies. ”

“ The residue may contain sulphates of lead, barium, or lime; it must be separately examined, if the total sulphur is wanted. The filtrate is heated, and rendered slightly alkaline with ammonia. Filter off the precipitated ferric hydrate through a quick filter, and wash with hot water. If necessary, evaporate the bulk to about 200 c.c., render faintly acid with hydrochloric acid, and add 20 c.c. of solution of barium chloride; allow to stand for half-an-hour, and decant through a filter. Wash with hot water, dry, ignite, and weigh. Pure pyrites contains 53.33 per cent. ”

“ This is effected by heating a mixture of the fuel with lime and sodium carbonate in a porcelain dish to redness in a muffle until all the carbonaceous matter has been burnt off. The residue, which contains the sulphur as calcium sulphate, is transferred to a beaker containing water to which a little bromine has been added. Hydrochloric acid is carefully added, the liquid filtered and the residue washed. To the filtrate ammonia is added, and then barium chloride, which precipitates the sulphur as barium sulphate. ”

“ This seems to prove that the radioactivity does not keep pace with the concentration of the barium compounds, but lags far behind. A reliable measure of the radium-amount is not furnished. Even a preparation of 3,500 activity must have consisted mainly of barium chloride, since it yielded 140 for the atomic weight which is only slightly in excess of that of barium. As to the activity of the purest radium chloride, we find no statements, but it is said that the best radium preparations have an activity of 50,000 to 100,000 times that of uranium. ”

“ Lengyel who doubts the existence of radium, succeeded in making barium active by heating its nitrate with uranylnitrate, and Henry Becquerel prepared a strongly active barium sulphate by precipitating by sulphuric acid a barium chloride solution to winch uranyl chloride had previously been added; in this case the activity of the uranium compound had at the same time diminished. Further K. A. Hofmann and E. Strauss have obtained inactive fractions from active uranium compounds ”

“ If sulphuric acid is present it must be separated by treating the solution of the compound with barium chloride and filtering. A nearly neutral solution is prepared in water or hydrochloric acid and placed in a flask. Here it is treated with chlorine by passing a current of that gas through it as long as it causes a precipitate and for some time afterward. ”

“ The filtrate contains only the alkali that was originally present as hydrate, the carbonate of soda having formed with the barium chloride, insoluble barium carbonate, and sodium chloride.
Bleaching Powder.—The value of bleaching powder {206} depends upon the amount of available chlorine that it contains. This is determined by means of a standard solution of arsenious acid. The standard solution is prepared by dissolving pure arsenious oxide (As2O3) in sodium carbonate solution. ”

“ Barium occurs chiefly in the form of barytes or heavy spar, BaSO4, and witherite, BaCO3, and to a less extent in baryto-calcite, baryto-celestine, and various complex silicates. The metal is difficult to isolate, and until recently it may be doubted whether the pure metal had been obtained. Sir H. Davy tried to electrolyse baryta, but was unsuccessful; later attempts were made by him using barium chloride in the presence of mercury. In this way he obtained an amalgam, from which on distilling off the mercury the barium was obtained as a silver white residue. ”

“ Generally induced radio-activity obtained in this way scarcely lessens with lapse of time, but it does not as a rule withstand many successive chemical changes of the active body.
79M. Debierne made active barium by placing it in solution with actinium. This barium remains active after several chemical reactions, its activity being therefore a somewhat stable atomic property. Active barium chloride fractionates like barium-radium chloride, the more active portions being the least soluble in water and dilute hydrochloric acid. ”

“ The mass becomes semi-liquid, and when it evolves carbonic oxide the heating is stopped. The following double decompositions proceed during this operation: first the carbon takes up the oxygen from the barium sulphate, and gives sulphide, BaS, which enters into double decomposition with the chloride of manganese, MnCl2, forming manganese sulphide, MnS, which is insoluble in water, and soluble barium chloride. ”

“ In the paper above named, by P. Carles, we are told that ‘owing to the injurious nature of the impurities of plastered wines, endeavours have been made to free them from these by a method called “deplastering,” but the remedy proves worse than the defect.’ The samples analysed by Carles contained barium salts, barium chloride having been used to remove the sulphuric acid. In some cases excess of the barium salt was found in the wine, and in others barium sulphate was held in suspension. ”

“ From the observations which I have made since I have made use of chloride of barium, I conclude that it has the effect of destroying any injurious properties which may be in the paper, and more especially with respect to the SIZE; and besides which, when combined with iodide of silver, greater intensity is obtained in the negative. ”

“ If required chemically pure, gaseous hydrochloric acid is transmitted through a concentrated solution of common or impure chloride of barium, as long as a precipitate forms; the resulting crystalline powder, which is nearly the whole of the chloride of barium present, is collected on a filter, and, after draining, is washed repeatedly with small quantities of pure hydrochloric acid, until the washings, diluted with water, and precipitated with sulphuric acid, give a filtrate which, upon evaporation in a platinum capsule or a watch-glass, leaves no residue ”

“ They have not been separated perfectly from their analogues, and consequently their chemical properties and the actual intensity of their physical activities is very imperfectly known. The difficulties of securing even small quantities of crude materials are enormous; Fritz Giesel obtained from one thousand kilograms of raw material only fifteen grams of active compounds, and Mme. Curie, operating on half a ton of the residues of uranium from a chemical manufactory, got about two kilograms of barium chloride rich in radium, but the percentage of active substances in these mixtures is unknown. ”

“ The chloride of strontium (which resembles that of barium in many properties, but which must be carefully distinguished, as it is not poisonous) , differs in the form of the crystals, which are delicate six-sided prisms, while those of the barytic salt are four-sided tables, often truncated on two opposite angles, sometimes on all four,—by its solubility in alcohol, which does not take up the chloride of barium,—and by its effect on the flame of alcohol, which it colours rose-red, while the barytic salts colour it yellow. ”

“ It is also possible to standardize a hydrochloric acid solution by precipitating the chloride ions as silver chloride and weighing the precipitate, as prescribed under the analysis of sodium chloride to be described later. Sulphuric acid solutions may be standardized by precipitation of the sulphate ions as barium sulphate and weighing the ignited precipitate, but the results are not above criticism on account of the difficulty in obtaining large precipitates of barium sulphate which are uncontaminated by inclosures or are not reduced on ignition. ”

“ Carbonate of potassium frequently contains an undue quantity of water, as well as silicic acid, sulphates, and chlorides. The water may be detected by the loss of weight the salt suffers when heated; the silica, by adding to it hydrochloric acid in excess, evaporating to dryness, and igniting the residuum, by which this contamination is rendered insoluble; the sulphates and chlorides may be detected by adding nitric acid in excess, and testing the liquid with nitrate of silver and chloride of barium. If the former produces a white precipitate, a chloride is present ”

“ Obtained by distilling cautiously potassium permanganate and sulphuric acid. Dark violet-black liquid, green by reflected light, and rapidly absorbing water forming a violet solution. Oxidises organic matter with explosive violence.
Permanganate of Barium. Ba (MnO) 45. Black soluble prisms, formed by decomposing silver permanganate by means of barium chloride, and cautiously evaporating.
Permanganate of Potassium. KMnO4. Prep. Potassium chlorate, or nitrate, and potassium hydrate are made into a paste with water, and manganic peroxide added; the mass is dried and heated to redness. ”

“ Fatal Dose.—The recorded cases of poisoning have not satisfactorily settled the question as to the least fatal dose of the barium salts. 6·5 grms. (about 100 grains) of the chloride have destroyed the life of an adult woman in fifteen hours; 14 grms. (1⁄2 oz.) of the nitrate of baryta have killed a man in six and a half hours; and the carbonate of baryta has destroyed a person in the relatively small dose of 3·8 grms. ”

“ Especially remarkable are the experiments of A. Debierne, which have been conducted in a similar manner with actinium, and by which it was proved that it is easy to make active the compounds of barium so that they scarcely differ from those of radium, except that they do not give a radium spectrum. The active barium is said to stand between barium and radium, its anhydrous chloride is self-luminous like that of radium, and may equally well, by fractional crystallization, be separated in a more active and a less active portion. ”

“ It is found in the crude state abundantly in nature, but can only be obtained absolutely pure by adding an alkaline carbonate to a solution of chloride of barium, or by saturating the hydrate with carbonic anhydride, and in either case washing and drying the precipitate. ”

“ The precipitate carries down the active body.
(4) Precipitation of insoluble sulphates. If barium sulphate, for example, is precipitated in the solution containing the active body, the barium carries down the active matter. The thorium and actinium are freed from the barium by conversion of the sulphate into the chloride and precipitation by ammonia.
In this way Debierne has obtained a substance comparable in activity with radium. The separation, which is difficult and laborious, has not yet been carried far enough to bring out any new lines in the spectrum. ”

“ The fused chlorides of barium and strontium suffer a very slight change in ammoniacal gas in many days; after more than a fortnight, the chloride of strontium, weighing about 30 grains, had absorbed only a cubical inch of gas, and a slight efflorescent appearance was seen on the broken edge.
A piece of fused chloride of silver, weighing about 80 grains, placed in ammoniacal gas, gradually absorbed more than 40 cubical inches. The action took place over the whole surface of the mass, but most speedily at the fractured edges. The chloride swelled considerably, and crumbled into powder. ”