SODIUM. 



SODIUM. 



ratdy beating sodium in tamo gat. It burn* vividly, evolving much 

 liw-lit and nest ; the peroxide resulting in of yellowish-green colour. 

 \\'li-u put into water, it u decomposed, oxygen go* being evolved, and 

 soda, or protoxide of (odium, remaining in solution. 



U is not applied to any uee, and, being deoompowd by wat. > . it 

 doet not form nlU with aekk. 



CHIorvu ad todi*m form only one compound, the important one, 

 common salt, formerly called muriate of soda, and now cMoridt of 

 Kxlimn (NaCU. Of all natural soluble saito this occur* in the greatest 

 quantity. It is mat with solid, constituting rvci talt, in solution in 

 salt springs and in the ooean, and in small quantity in almost all 

 spring and river water. [SALT-TRACK ; Sowi M. in NAT. H IST. Div.] 



This aalt may bo obtained artificially, either by the direct action of 

 chlorine gas on sodium, or by saturating hydrochloric acid with soda ; 

 iiy evaporating the solution, common salt is obtained, which, in what- 

 ever manner or from whatever source procured, bos, when pure, the 

 following properties : it is colourless, inodorous, has a purely saline 

 taste unmixed with bitterness; is transparent, brittle, and easily 

 reduced to powder ; its specific gravity is about -I:!.".: when exposed 

 to moist air, it deliquesces ; it crystallises in cubes, which form under 

 tuuces is but little subject to modification. It is 

 almost as soluble in cold water as in boiling. \\ ater at 32" dissolves 

 more than at 60* ; 100 parts of water at 58* dissolve 36 of salt, and in 

 a boiling saturated solution, tin- temperature of which is 229*5, 100 

 part* of water hold 41 "2 of salt in solution. A saturated boiling solu- 

 tion does not deposit crystals on cooling, evaporation being necessary 

 to produce this efl'ect ; in pure alcohol it is insoluble. At a red heat 

 common salt fuses, and on cooling it becomes a transparent brittle 

 inisfl ; UK crystals contain no water of crystallisation, but decrepitate 

 strongly when heated, owing to the eipansion of mechanically inter- 

 posed water. At a bright red heat it sublimes in the air, and tinges 

 uane of a blue colour. 



The uses of this aalt have been known from the earliest ages. It is 

 employed not only in seasoning food, but in preserving meat from 

 putrefaction. It is used occasionally as a manure. In chemical manu- 

 factures it is employed for preparing hydrochloric acid, sulphate and 

 carbonate of soda, and several other salts, and in the preparation of soap. 



Sodium combines with fluorine, bromine, iodine, sulphur, phos- 

 phorus, &c. ; the compounds which they form are unimportant, not 

 being extensively applied to any useful purposes. Their formation is 

 accomplished by methods similar to those employed in the preparation 

 of the corresponding salts of POTASSIUM. 



Salt* of Oxide of Sodium, or Osimlti of Soda. 



It is perhaps scarcely requisite to state that these salts are never 

 prepared by directly acting upon the metal sodium, although for pur- . 

 poses of curiosity they might all of them be so procured. The first 

 which we shall notice is 



Jfitratt of Soda (NaO, NO,). -This salt may be prepared either by 

 adding the metal, or soda, its oxide, to nitric acid ; us a natural product 

 it has, however, of late yean been largely imported from Peru, where 

 it forms a deposit similar to that of nitrate of potash in India. Nitrate 

 of soda has a cooling saline taste, is inodorous and colourless; in a 

 moist atmosphere it deliquesces ; it readily crystallises, and the form 

 of the crystal is an obtuse rhomboid ; so obtuse indeed, and so near a 

 cube, that the salt was originally called cubic nitre, to distiii; 

 fn>m potash nitre, the crystals of which are prismatic. According to 

 Gay-Lusaac, 1 00 parts of water at 32 dissolve 73 parts of this salt ; 

 and at 212, 173 parts : water at 60 dissolves half its weight. It is 

 sometimes found with crude nitrate of potash. 



Like nitrate of potash, it deflagrates with charcoal ; but owing to its 

 property of attracting moisture, it cannot be used in the manufacture 

 of gunpowder. It is, however, used largely in making nitric acid, 

 sulphuric acid, and as a manure. 



There are three compounds of carbonic acid and soda; namely, 

 1 , carbonate ; 2, Kvpti-carbonate ; and 3, bi-ca,rbonate. 



1 . Carbonatf of Soda (NaO, CO, +10 Aq.). This salt, formerly called 

 mbtarbonatc of toda, was obtained from barilla, or kelp : the former 

 being the ashes of the Solatia *'/' red in Spain; the latter 



the ashes of burnt sea-weed, manufactured in Scotland. Since the 

 1 duty has been taken off common salt, carbonate of soda is prepared, for 

 the numerous uses to which it is applied, by first converting common 

 >lt into sulphate of soda by means of sulphuric acid, and then treating 

 the sulphate, or sail-cake, as it is called, with small -coal and chalk in 

 a reverberatory furnace ; the result is a mixture of carbonate of soda 

 and oxysulphide of calcium, termed lull-toda, or Uack-ath, when this 

 u treated with cold water, the oxysulphide remains uudissolved, while 

 the carbonate of soda is taken up by the water, and by evaporation to 

 <lryness yields what is called ioda-aeJt. 



Carbonate of soda is a colourless, inodorous salt; it is devoid of 

 niell, but has a disagreeable taste, though less so than carbonate of 

 Ita*h ; it is readily soluble in water. The primary form of this 

 piibstance, when crystallised by moderate evaporation of the solution, 

 is an oblique rhombic prism. The crystals are frequently very large. 

 They contain about 62 per cent, of water, the greater part ol 

 they lose by exposure to the iiir, and efflorescing, fall to powder. At 

 high temperatures the salt becomes fluid and boils. Water at 60 

 dissolves half its weight of carbonate of soda, and boiling water con 



siderably more. The solution possesses the alkaline property of turning 

 vegetable yellows brown. Like other carbonates, this salt is decom- 

 posed by the stronger acids, with effervescence of carbonic acid ; and 

 by lime, which separates its carbonic acid, it is rendered caustic. 



The quantity of this salt prepared and used is enormous; it is 

 required in making soap, and crown and plate glass, and for uui< 

 other purposes. 



^ui-carbmate of Soda (2NaO, HO,3CO, + 3Aq.). This com- 

 pound is found native in Hungary, and also near Fezzan in Africa. 

 By the natives it is called Trona. It is found in hard striated crystalline 

 nmmin. is not altered by exposure to the air, and is readily soluble in 

 water. 



Thin salt appears to be formed when a solution of the carbon 

 soda is heated with carbonate of ammonia, and probably al-<> 

 solution of the bi carbonate is heated. Its taste U less alkaline than 

 that of the carbonate, into which it is converted, when strongly heated, 

 by losing one-third of its carbonic acid. 



Bicarbonate of .Soda (NaO, HO, 2CO,). This aalt may bo formed 

 by passing carbonic acid gas into a solution of the carbonate of soda ; it 

 is a crystalline granular compound. It is produced on the large scale 

 by exposing crystals of carbonate of soda to a current of c 

 . i'i | . . 



Bi carbonate of soda has a very slightly alkaline taste, and acts very 

 feebly on turmeric-paper. It requires about twelve times its weight of 

 water for solution. When the solution is boiled, it loses one-fourth of 

 its carbonic acid, and is converted into sesqui-corbonate ; at a re 1 heat 

 it loses all its water and half its carbonic acid, 

 ing. It resembles the se&qui-carbonate in giving n 

 the salts of magnesia till heated; and they both i the 



carbonate in this respect. It is used in medich; , or at 



least should be, a solution of bi-carbon.-ite of soda in water charged with 

 carbonic auid gas under pressure. [ AKKATLU WATKUS.] 



Xul/./iate of Soda (NaO, SO, + lOAq.), formerly e.ii; 

 null, may be formed by the direct combination of the acid .ind alkali ; 

 it is, however, generally pu-paird l>y decomposing common sail , 

 the preparation of hydrochloric auid, or of carbonate of soda. It has 

 also been met with in nature, but not largely, [Sunn M. iu NAT. 

 HIST. Div.] 



This salt is readily soluble in water, and the solution by evaporation 

 yields colourless transparent prismatic crystals, the primary i . 

 which is an oblique rhombic prism. It has a very bitter taste; 

 effloresces when exposed to the air, by losing water of crystalli 

 Boiling water dissolves its own weight of this .salt, ami v 

 one-third of its weight. It is, however, most soluble at i*3 Fahr. ; at 

 that temperature 100 ports of water will dissolve 50 c !m salt. 



A boiling saturated solution of sulphate of soda may In- cool 

 kept for months without any crystals forming in it, provided that air 

 be excluded; let, however, a crystal of the sulphate, or any solid 

 matter, even a particle of dust, be dropped into the liquid, aj 

 whole then shoots into crystals with considerable elevation of tempera- 

 ture. Sulphate of soda is insoluble in alcohol. When exposed to 

 heat it lii'-t undergoes watery fusion, by mulling in its water of 

 crystallisation ; when the water has been expelled, it becomes opaque 

 white, and at a red heat it melts. 



An anhydrota tulphate of soda, and a hydrate containing Na' 

 + 7A<j. may also be obtained. ISitulphatc of toda contains NaO. lie 

 2SO 3 . 



t-ii/jtliUe of Soda (NaO, SO, + 7Aq.) is formed on passing sulphurous 

 acid gas over carbonate of soda. It is used by paper Manufacturers, 

 under the name of aaticlilur, for removing tli 

 from thuir rag-pulp. Jiitulphite of soda contains NaO, HO, 2SO,. 



silicate* of Soda. [SILICON; GLASS.] 



Acetate of Soda. [ACETATE.] 



Phoephoric Acid combines with soda to form several compounds. 

 [PHOSWIOKUS.] 



/.';(< of Soda is a compound of boracic acid and soda. [Uono.\. ] 



For an account of numerous other salts of soda we must re 



.1 treatises; thote whose properties we have detailed being 

 merely uful. 



'" of the, Sato of Sodium. Unlike the na 

 potash, there is no acid nor any metallic oxide which forms a pi i 

 insoluble compound with the salts of soda, BO ili.it th.y cann 



in combination from solution. The In 

 !iing between these two alkalies is, by the yellow . 

 soda salts communicate to the Wow-pipe llame, salts of p..: 

 violet tinge. They are separated from each other !>\ taking adva 

 of the insolubility of the double chloride of platinum and potassium, 

 and the great solubility of the corresponding sodium salt. 



SODIUM, Medical Prvpertiet of the 7V.//n<-.i Hum. when 



in the state of an oxide, is termed the mineral alkali, in contradistinc- 

 tion to potash, or the vegetable alkali. 



Sodium possesses the ordinary qualities of a fixed alkali, but not- 

 withstanding the resemblance it ha 

 with the same acid, present some differences which may be here 



pointed OUt. 



In the oxidised state, or soda (pure or caustic), sodium 

 employed in medicine to counteract acidity; nor in surgery tn form 

 an ulcer or to open abscesses, though for this latter purpose it possesses 



