HARIt'Sl. 



BARIUM. 



M4 



BA'RIUM (Ba), a peculiar metal, the haoU of the alkaline earth 

 baryU. Dary first gutted mdkaticoi of the decomposition of baryta 

 in the end of October 1807 ; he obuined an alloy of it with irou in 

 March 1808 ; and in the beginning of June, in the eune year, he 

 obtained toe metal. To prepare barium, a quantity of the mineral 



> called carbonate of baryta is made into a paite with water, 

 and placed on a pUte of platinum ; a cavity U made in the paste to 

 receive a globule of mercury ; the mercury i rendered negative, the 

 iJatimim positive, by mean* of a Voltaic battery nontaining about one 

 hundred double plate*. In a abort time, the baryta of the carbonate 

 | decomposed, my| an amalgam of mercury and barium formed. This 

 i niunt be heated in a umall bent glass tube, which contains no 



lead, and filled with hydrogen gu, or the va|.ur of naphtha; the 

 mercury being volatilised, the barium remains. Barium may abto be 

 procured, without the aid of rUvtricity . by passing a current of the 

 vj|>nr of potassium over red-hot baryta in an iron tube. By thin a 

 mixture of barium and oxide of potaiaium ia obtained ; from this the 

 metal ia to be extracted by amalgamation with mercury, and the amal- 

 gam a to be decomposed by heat in the mode already deaoribed. These 

 method* do not give Ui metal in a state of purity , but it may be obtained 

 pure by the voltaic decomposition of its fused anhydrous chloride. 



Barium U a yellow metal of considerable lustre. It is much 

 heavier than water, for it sinks even in sulphuric acid, though 

 urrounded by bubbles of gas. It decomposes water readily, with 

 the evolution of hydrogen gas ; a solution of baryta ia thus obtained. 

 By exposure to the air, it is slightly covered with a crust of baryta ; it 

 fuse* before it becomes red hot, and at this temperature it acta upon 

 glass, without being volatilised. When exposed to the air, and mode- 

 rately heated, it burns with a deep red light It may be flattened a 

 little, so that it ia to a certain extent a malleable metal. Barium has 

 however as yet been obtained only in small quantities, and consequently 

 iU properties are but imperfectly known. The equivalent of barium is 

 flS'84. Barium forms two compounds with oxygen, a protoxide and 

 a binoxide. 



Protoxide of Barium (BaO); Baryta ; Baryta. This oxide in combi- 

 nation occurs largely in nature, and was discovered in the year 1774 by 

 Scheele ; iU name is derived from ffafus (oaryt), heavy. Baryta is met 

 with combined with sulphuric acid, forming licary ipar or faint, termed 

 chemically sulphate of baryta, and with carbonic acid, constituting the 

 mineral termed vitherite, or carbonate of baryta ; it may be procured 

 by decomposing either of these native compounds. The simplest 

 mode, when it ia wanted free from water, is to convert the carbonate 

 into nitrate of baryta, and this when strongly heated in an earthen 

 crucible is decomposed, and the nitric acid being expelled, the baryta 

 remaining baa the following properties : It is of a grayish-white colour. 

 When moistened with water it becomes very hot, and in a short time 

 falls into a fine white powder ; if more water is added, it becomes a 

 crystalline and very hard mass. The specific gravity of baryta is about 

 4-0 ; it is extremely poisonous, baa an acrid, alkaline, caustic taste, and 

 requires a high temperature to fuse it. 



Baryta, or the protoxide of barium, is composed of 



1 equivalent of oxygen ..... 8 

 1 do. barium 68'64 



76-64 



Baryta and water combine and form at least two compounds : the 

 first hydrate, is procured when a small quantity of water ia poured 

 upon baryta, and during their action, as has been already stated, much 

 beat is evolved, and the baryta becomes a white powder. This hydrate 

 contains one equivalent of water ; it is fusible at a red heat, but does 

 not part with its water even when heated to whiteness.. 



According to Davy, 20 part* of water at 60 dissolve one part of 

 baryta : the solution is called baryta water, and is frequently used as a 

 chemical re-agent With carbonic acid baryta forms an insoluble car- 

 bonate, and both baryta and baryta water speedily acquire carbonic 

 add by exposure to the air. Baryta water acts strongly as an alkali, 

 converting vegetable yellows to brown, restoring the blue colour to 

 reddened litmus, and saturating acids. Water at 21 2 dissolves, by 

 Davy's experiments, half its weight of baryta, of which a considerable 

 portion separates in the state of crystals as the solution cools ; these 

 crystals contain ten equivalents of water. 



Peroxide of Barium (BaO,), Binoxide of Barium, is prepared by 

 heating baryta to low redness in a platinum crucible, gradually adding 

 to it about one-fourth of its weight of chlorate of potash ; this yields 

 oxygen to the baryta or protoxide of barium, which thus becomes per- 

 oxide, but mixed with chloride of potawum, which may be dissolved 

 by cold water, while the peroxide of barium remains umliasolved, com- 

 bined with water ; it may also be prepared by pawing oxygen gas over 

 baryta heated to redness. It is composed of two equivalents of oxygen 

 and one equivalent of barium. It is decomposed by acids, and is used 

 only in preparing the binoxide of hydrogen. 



Neither nitrogen nor hydrogen unites with barium. 



CUoridt of Barium iBaCl + 2HO). Chlorine and barium combine to 

 form one chloride, consisting of 



1 equivalent of chlorine .... 35-47 

 1 do. bnritun 08-64 



104-11 



The best mode of preparing chloride of barium is to dissolve car- 

 bonate of baryta in hydrochloric acid, and evaporate the solution so as 

 to obtain crystals, which lmuld be then purified by 

 Chloride of barium is a colourless salt, soluble in water, but insoluble 

 in alcohol. Ki\e juris of water at 60* dissolve one port uf chloride of 

 barium. Chloride of barium U used a* a chamical re-agent fur the 

 detection and quantitative determination of sulphuric acid. 



Pntotidpkide of Barium (Bag). Sulphur and barium combine in 

 several proportions, but the protosulphide is tin- only rum|.,.mnl of 

 importance. It may be prepared by heating together finely-poll 

 sulphate of baryta and powdered charcoal in a covered orudbb ; in this 

 case the charcoal takes oxygen both .from the sulphuric acid and tl,.- 

 baryta, and protosulphide of barium remains, which dissolves readily 

 in boiling water, and the solution on cooling deposits colourless trans- 

 parent crystals; these crystals are protosulphide of barium, containing 

 six equivalents of water. 



I'rotufmlphide of barium thus prepared U much used for the pro- 

 duction of other salta of barium, as it ia readily decompose* I 

 acids, even the carbonic acid. Thus chloride of barium may be i 

 by adding hydrochloric acid to protogulphide uf barium. 



BsS + HC1 = BsCl + IIS. 



/hide of Barium (BaP). Pluaphuret of Jlari i.liuru 



and barium combine to form the phosphide, by heating baryta i 

 ness in a glass matrass with a long neck, and throwing 

 upon it. There are formed both phosphate of baryta and p 

 of barium, as represented in the following equation : 

 7BO + 6P = SBaP + 2BuO, PO S 



Baryta. 



Phosphide of 

 Barium. 



Phosphate of 

 Baryta, 



The mass fuses, and on cooling has a brown colour and a i 

 lustre. When too strongly heated the phosphide of liarium is decom- 

 posed, phosphorus is volatilised, and baryta remains. Phosph 

 barium decomposes water ; phosphuretted hydrogen gas is evolve, ! 

 hypophosphite of baryta remains in solution. 



Iodide uf liarium (Bal). Iodine and barium unite and form tin- 

 iodide of this metal. It may be prepared by acting upon baryta or il~ 

 carbonate with hydriodic acid, and evaporating the solution obtained. 

 It is very soluble in water, and crystallises in acicular crystals, which 

 deliquesce slightly by exposure to the air. 



Bromide of Barium (HaBr + 2HO). Bromine and barium, when 

 combined, form the bromide. It may be obtained by boiling excess of 

 moist carbonate of baryta in a solution of protobromide of iron ; the 

 filtered solution is to be evaporated to dryness and the residue mode 

 red hot ; by dissolving this in water, and by careful evaporation, colour- 

 less rhombic crystals are obtained, which are soluble in alcohol. 



Fluoride of liarium (BaF). Fluorine and barium may be made to 

 combine by digesting fresh precipitated and moist carbonate of baryta 

 in hydrofluoric acid ; the carbonate is decomposed, and the fluoride of 

 barium is formed, and separates in the state of a white powder. This 

 may be heated to redness without decomposing, and is slightly soluble 

 in water. The solution, by evaporation, yields crystalline grains, which 

 are readily dissolved by hydrochloric and nitric acids. 



Having described the principal binary compounds of Kuium. w<- 

 proceed to notice the more useful of the numerous salts formed by 

 combining the protoxide of liarium (baryta) with different acids. The 

 following are the only barytic salts which are extensively employed. 



Acetate of llari/ta (BaO, C.H,0, + 3HO). This salt may ],< ],', 

 by dissolving either baryta or the carbonate in acetic acid, or 

 posing the solution of protosulphide of barium with it. By evaporation, 

 crystals of acetate of baryta are obtained in slender prisms, resembling 

 those of acetate of lead. These crystals effloresce by exposure to the 

 air; they dissolve in 176 part of cold water, and in 1-08 of boiling 

 water ; 100 parts of cold alcohol dissolve one part of these cryst, 

 when boiling, one part and a half. This salt is composed of 



1 equivalent of acetic acid . . . . M-n 



1 do. baryta 76'fl 



8 do. water 27'0 



154-6 



The taste of this salt U saline and bitter. It is decomposed by the 

 fixed alkalies and their carbonates, and by carbonate of ammonia : it is 

 also decomposed by sulphuric acid and the sulphates, which precipitate 

 sulphate of baryta. 



According to Mitacherlich, when this salt crystallises at the tempe- 

 rature of 65 Fahrenheit, it contains only 6*6 per cent, uf water; but 

 when below this temperature it contains, as above stated, about 17'6 per 

 cent, of water of crystallisation. 



Carbonate of /toryta (BaO, CO,). This substance occurs to a con- 

 siderable extent as a mineral product . and is I >y mineralogists sometimes 

 called vitherite. It is a dense substance, its specific gravity being about 

 4-381 ; it is sometimes translucent and nearly colourless, but is often 

 opaque. It sometimes occurs crystallised, and the primary form is a 

 right rhombic prism, but it usually hat; the form of a six i.l'.-d |.i 



Carbonate of baryta is so nearly insoluble in water as to : 

 about 4800 times its weight at 60, and 2300 at 212 for solution : and 



