See also:element belonging to the
See also:group of
See also:alkali metals . It is abundantly and widely diffused in nature, but always in combination . Sodium chloride, or
See also:salt (q.v.), is exceedingly common, being the chief salt
See also:present in
See also:water, besides occurring in extensive stratified deposits . Sodium
See also:carbonates are also widely dispersed in nature, forming constituents of many
See also:waters, and occurring as
See also:principal saline components in
See also:patron or trona lakes, as efflorescences in
See also:Persia and
See also:China, and as urao in Mexico,
See also:Colombia and
See also:Venezuela . The solid crusts found at the bottom of the salt lakes of the Araxes plain in Armenia contain about 16% of carbonate and 8o of sulphate . In Colombia there occurs a
See also:double salt, Na2COa• CaCOa•5HQO, known as gay-lussite . In
See also:Wyoming, California and
See also:Nevada enormous deposits of carbonates, mixed in some cases with sulphate and with chloride, occur . About Szegedin in Hungary and all over the vast pusztas (
See also:steppes) between the Theiss and the
See also:Danube, and from the Theiss up to and beyond Debreczin, the
See also:soil contains sodium carbonate, which frequently assumes the
See also:form of crude alkaline crusts, called " szekso," and of small saline ponds . A purified specimen of such Debreczin soda was found to contain as much as 90 % of real carbonate, NaCO3, and 4 of common salt Natural sulphate occurs in an anhydrous
See also:condition as thenardite, NaeSOr, at
See also:Tarapaca, Chile, and in the
See also:rock-salt deposits at Espartinas near Aranjuez, Spain . Hydrated sulphates occur at several localities in the province of
See also:Madrid and in other provinces of Spain, and at Muhlingen in
See also:Aargau, and copious deposits of glauberite, the double sulphate of sodium and calcium, are met with in the salt-mines of Villarrubia in Spain, at
See also:Stassfurt, and in the province of Tarapaca, Chile, &c . A native nitrate of soda is obtained in
See also:great abundance in the
See also:district of Atacama and the province of Tarapaca, and is imported into
See also:Europe in enormous quantities as cubic
See also:nitre for the preparation of saltpetre .
See also:Cryolite, a fluoride of aluminium and sodium, is extensively
See also:mined in
See also:Greenland and elsewhere for
See also:industrial purposes .
These form the principal natural
See also:sources of sodium compounds—the chloride as rock salt and in sea-water being of such predominating importance as quite to outweigh all the others . But it is questionable whether, taken altogether, the mass of sodium they represent is as much as that disseminated throughout the rocky crust in the form of soda
See also:felspar (i.e. as silicate of soda) and in other soda-containing rocks . From this source all soils contain small proportions of sodium in soluble forms, hence the ashes of
See also:plants, although they preferably imbibe potassium salts, contain traces and sometimes notable quantities of sodium salts . Sodium salts also form essential ingredients in all animal juices . Although many sodium compounds have been known from very remote times, the element was not isolated until 1807, when
See also:Sir H .
See also:Davy obtained it by electrolysing
See also:caustic soda . This method was followed by that proposed by Gay-Lussac and
See also:Thenard, who decomposed molten caustic soda with red-hot iron; and this in turn was succeeded by
See also:process of igniting sodium carbonate with
See also:charcoal . Deville made many improvements, but the method remained wasteful and uneconomical, and in 1872 the
See also:metal cost 4s. a pound . In 1886, however, Castner replaced the carbonate by caustic soda, and materially cheapened the cost of production; but this method was discarded for an electrolytic one, patented by Castner in 1890 . Electrolytic processes had, in fact, been considered since 1851, when
See also:Watt patented his method for the production of sodium and potassium from fused chlorides . Among the difficulties here to be contended with are the destructive
See also:action of fused chlorides and of the reduced alkali metals upon most non-metallic sub-stances available for the containing vessel and its
See also:partition, and also of the anode chlorine upon metals; also the low fusing-point (95° C. for sodium, and 62° C. for potassium) and the low specific gravity of the metals, so that the separated metal floats as a fused layer upon the top of the melted salt . Again, pure sodium chloride melts at about 7750 C., while sodium boils at 877° C., so that the margin of safety is but small if loss by
See also:vaporization is to be prevented .
Borchers endeavoured to
See also:con-tend against the first difficulty by employing an iron
See also:cathode vessel and- a chamotte (
See also:clay) anode chamber
See also:united by a specially constructed water-cooled joint . The other difficulty is to some extent met by using mixed chlorides (e.g. sodium, potassium and strontium chlorides for sodium extraction), as these melt at a lower temperature than the pure chloride . In Castner's process (as employed at
See also:Oldbury and Niagara Falls and in Germany) fused caustic soda is electrolysed . The apparatus described in the patent
See also:specification is an iron cylinder heated by
See also:gas rings below, with a narrower cylinder beneath, through which passes upwards a stout iron cathode
See also:rod cemented in place by caustic soda solidified in the narrower vessel . Iron anodes are suspended around the cathode, and between the two is a cylinder of iron
See also:gauze at the bottom with a
See also:sheet-iron continuation above, the latter being provided with a movable cover . During electrolysis,
See also:oxygen is evolved at the anode and escapes from the
See also:outer vessel, while the sodium deposited in globules on the cathode floats upwards into the iron cylinder, within which it accumulates, and from which it may be re-moved at intervals by means of a perforated iron ladle, the fused salt, but not the metal, being able to pass freely through the perforations . The sodium is then
See also:cast into moulds . Sodium hydroxide has certain advantages compared with chloride, although it is more costly; its fusing-point is only 320° C., and no anode chlorine is produced, so that both containing vessel and anode may be of iron, and no porous partition is necessary . Metallic sodium possesses a silvery lustre, but on exposure to moist air the
See also:surface is rapidly dulled by a layer of the hydroxide . It may be obtained crystallized in the quadratic
See also:system by melting in a sealed
See also:tube containing hydrogen, allowed to cool partially, and then pouring off the still 'liquid portion by inverting the tube . The specific gravity is 0.9735 at 13.50(Baumhauer) . At ordinary temperatures the metal has the consistency of
See also:wax and can be readily cut; on cooling it hardens .
See also:heating it melts at 95.6° (
See also:Bunsen) to a liquid resembling mercury, and boils at 877.5° (
See also:Ruff and Johannsen, Ber., 1905, 38, p . 36or), yielding a vapour, colourless in thin layers but a
See also:purple, with a greenish
See also:fluorescence, when viewed through thick layers . (For the
See also:optics of sodium vapour see R . W .
See also:Physical Optics.) According to A . Matthiessen, sodium ranks
See also:fourth to
See also:silver, copper and gold as a conductor of
See also:electricity and
See also:heat, and according to Bunsen it is the most electropositive metal with the exception of caesium, rubidium and potassium . The metal is very reactive chemically . Exposed to moist air it rapidly oxidizes to the hydroxide; and it burns on heating in air with a yellow flame, yielding the monoxide and dioxide . A fragment thrown on the surface of water rapidly disengages hydrogen, which gas, however, does not inflame, as happens with potassium; but inflammation occurs if hot water be used, or if the metal be dropped on moist
See also:filter paper . Sodium also combines directly, sometimes very energetically, with most non-metallic elements . It also combines with dry
See also:ammonia at 300-400° to form sodamide, NaNH2, a
See also:white waxy mass when pure, which melts at 1550 . Heated in a current of
See also:carbon dioxide sodamide yields caustic soda and
See also:cyanamide, and with nitrous
See also:oxide it gives sodium
See also:azoimide; it deflagrates with lead or silver nitrate and explodes with potassium chlorate .
Sodan3ide was introduced by Claisen (Ber., 1905, 38, p . 693) as a condensing
See also:agent in organic chemistry, and has since been applied in many directions . Sodium is largely employed in the manufacture of cyanides and in reduction processes leading to the
See also:isolation of such elements as magnesium, silicon,
See also:boron, aluminium (formerly), &c.; it also finds application in organic chemistry . With potassium it 'forms a liquid alloy resembling mercury, which has been employed in high temperature thermometers (See THERMOMETRY) . Compounds . In its chemical combinations sodium is usually monovalent; its salts are generally soluble in water, the least soluble being the metantimonate . Sodium hydride, NaH, is a crystalline substance obtained directly from sodium and hydrogen, at, about 400° . It burns when heated in dry air, and ignites in moist air; it is decomposed by water, giving caustic soda and hydrogen . Dry carbon dioxide is decomposed by it,
See also:free carbon being produced; moist carbon dioxide, on the other
See also:hand, gives sodium formate . Several oxides are known . A suboxide, . Na30, appears to be formed as a
See also:grey mass when a clean surface of the metal is exposed to air, or when pure air is passed through the metal just above its melting point (De Forcrand, Compt. rend., 1898, 12,7, pp .
344, 514)• The monoxide, Na2O, is obtained by heating the metal above 18o° in a limited amount of slightly moist oxygen (
See also:Holt and
See also:Sims, fourn . Chem .
See also:Soc., 1894, i . 442) ; It may also be prepared by heating the nitrate or nitrite with metallic sodium, free nitrogen being eliminated (German patent, 142467, 1902) . It forms a grey mass, which melts at a red heat and violently combines with water to give the hydroxide . The hydroxide or caustic soda, NaOH, is usually manufactured from the carbonate or by electrolysis of salt solution (see ALKALI MANUFACTURE) . When anhydrous it is a colourless opaque solid which melts at 310°, and decomposes at about 1 too° . It is very soluble in water, yielding a strongly alkaline solution; it also dissolves in
See also:alcohol . It absorbs moisture and carbon dioxide from the atmosphere . Several hydrates are known: 2NaOH•7H20 is obtained as large
See also:monoclinic crystals by cooling a solution of specific gravity 1365 to -8°; Pickering (Journ . Chem . Soc., 1893, 65, p .
890) obtained NaOH•H2O from hot concentrated solutions and NaOH•2H2O from a solution of the hydroxide in 96 8 % alcohol . (See also De Forcrand, Compt. rend., 1901, 1331 p . 223.) Sodium dioxide, Na202, is formed when the metal is heated in an excess of air or oxygen . In practice the metal is placed on aluminium trays traversing an iron tube heated to 3000, through which a current of air, freed from moisture and carbon dioxide, is passed; the process is made continuous, and the product contains about 93 % Na2O2 . Wt.en pure, sodium dioxide has a faint yellowish tinge, but on exposure it whitens (W . R . 13ousfield and T . M . Lowry, Phil . Trans., 1905, A . 204, p: 253) . When dissolved in water it yields some NaOH and H202; on cr'stallizing a
See also:cold solution Na202 81120 separates as large
See also:tabular hexagonal crystals, which on drying over sulphuric acid give Na202 2H20, the former is also obtained by precipitating a mixture of caustic soda and hydrogen peroxide solutions with alcohol .
Acids yield a sodium salt and free oxygen or hydrogen peroxide; with carbon dioxide it gives sodium carbonate and free oxygen; carbon monoxide gives the carbonate; whilst nitrous and nitric oxides give the nitrate . A solution in hydrochloric acid, consisting of the chloride and hydrogen peroxide, is used for '
See also:straw under the name of soda-bleach; with calcium or magnesium chlorides this solution gives a solid product which, when dissolved in water, is used for the same purpose (Castner, Journ . Soc . Chem . Ind., 1893, p . 603) . Sodium dioxide is chiefly employed as an oxidizing agent, being used in mineral analysis and in various organic preparations; it readily burns paper, wood, &c., but does not evolve oxygen unless heated to a high temperature . Sodyl hydroxide, NaHOs, exists in two forms: one, Na•O.OH, obtained from hydrogen peroxide and sodium ethylate; the other, O:Na.OH, from absolute alcohol and sodium peroxide at o° . They are strong oxidizing agents and yield alkaline solutions which readily evolve oxygen on heating . Sodium trioxide, Na20s, is said to be formed from an excess of oxygen and a solution of sodammonium in liquid ammonia . Water decomposes it, giving oxygen and the dioxide . Generally speaking, sodium salts closely resemble the corresponding potassium salts, and their methods of preparation are usually the same .
For sodium salts not mentioned below reference should be made to articles wherein the acid is treated, unless otherwise indicated . Sodium combines directly with the
See also:halogens to form salts which are soluble in water and crystallize in the cubic system . The fluoride, NaF, is sparingly soluble in water (I
See also:part in 25) . For the chloride see SALT . The bromide and iodide crystallize from hot solutions in anhydrous cubes; from solutions at ordinary temperatures in monoclinic prisms with 2H20; and at low temperatures with 5H20 . According to M . Loeb (Journ . Amer . Chem . Soc., 1905, 27, p . I019) the iodide differs from the other haloid salts in separating from solution in alcohols with " alcohol of
See also:crystallization." Sodium sulphide, Na2S, obtained by saturating a caustic soda solution with sulphuretted hydrogen and adding an
See also:equivalent of alkali, is employed in the manufacture of soluble soda
See also:glass . Sodium sulphite, NasSOs, which is employed as an antichlor, is prepared (with 7H20) by saturating a solution of sodium carbonate with
See also:sulphur dioxide, adding another equivalent of carbonate and crystallizing .
The anhydrous salt may be prepared by heating a saturated solution of the hydrated salt . H .
See also:Hartley and W . H . Barrett (Journ . Chem . Soc., 1909, 95, p . 1184) failed to obtain a decahydrate which had been previously described . The acid sulphite, NaHSO3, obtained by saturating a cold solution of the carbonate with sulphur dioxide and precipitating by alcohol, is employed for sterilizing
See also:beer casks . Sodium sulphate, Na1SO•, known in the hydrated condition (with ioH2O) as
See also:Glauber's salt, is manufactured in large quantities for conversion into the carbonate or soda (see ALKALI MANUFACTURE) . It has long been doubted whether sodium yielded an
See also:alum; this was settled by N . I .
Surgunoff in 1909 (Abst . Journ . Chem . Soc. ii . IooI), who obtained cubic crystals from a supersaturated solution of sodium and aluminium sulphates below 20°, higher temperatures giving monoclinic crystals . The acid sulphate, NaHSO4, also known as bisulphate of soda, is obtained as large
See also:asymmetric prisms by crystallizing a solution of equivalent quantities of the normal sulphate and sulphuric acid above 5o° . The acid salts Na3H (SO4)s and NaiH(SO4)s•H20 are obtained from the normal sulphate and sulphuric acid (J . D'Ans; Ber., 1906, 39, p . 1534) . The manufacture of sodium carbonate, commonly called soda, is treated under ALKALI MANUFACTURE . The anhydrous salt is a colourless powder or porous mass, having an alkaline taste and reaction . It melts at too8 .
On solution in water, heat is evolved and hydrates formed . Common washing soda or soda-crystals is the decahydrate, Na2CO3'I0H2O, which appears as large clear monoclinic crystals . On exposure, it loses water and gives, the monohydrate, Na2CO2.
See also:H2O, a white powder sold as " crystal carbonate "; this substance, which is also formed on heating the decahydrate to 34°, crystallizes in the rhombic system . Both these hydrates occur in the mineral
See also:kingdom, the former as natron and the latter as thermonatrite . The heptahydrate, Na2CO3.7H20, is obtained by crystallizing a warm saturated solution in a vacuum; it appears to be dimorphous . The acid carbonate or bicarbonate of soda, NaHCO3, is produced in the ammonia-soda process for alkali manufacture . Another acid carbonate, Na2COs 2NaHCO3.3Hs0, is the mineral trona or urao . We may here
See also:notice the " percarbonates " obtained by Wolffenstein and Peltner (Ber., 1908, 41, pppp 275, 280) on acting with gaseous or solid carbon dioxide on Na202, Na20s and NaHO2 at low temperatures; the same authors obtained a perborate by adding sodium metaborate solution to a 50 % solution of sodium peroxide previously saturated with carbon dioxide . For sodium nitrite see NITROGEN; for sodium nitrate see SALTPETRE; for the
See also:cyanide see PRUSSIC ACID; and for the borate see BORAX . Of the sodium silicates the most important is the mixture known as soluble soda glass formed by calcining a mixture of white sand, soda-ash and charcoal, or by dissolving
See also:silica in hot caustic soda under pressure . It is a colourless transparent glass mass, which dissolves in boiling water to form a thick liquid . It is employed in certain printing processes, as a
See also:cement for artificial
See also:stone and for mending glass,
See also:porcelain, &c., and also for making the so-called silicited soaps (see
See also:SOAP) .
GOMORRAH Sodium is most distinctly recognized by the yellow coloration which volatile salts impart to a Bunsen flame, or, better, by its emission spectrum which has a
See also:line (double), the
See also:Fraunhofer D, line, in the yellow (the
See also:wave-lengths are 5896 and 5890) . The 'atomic
See also:weight was determined by
See also:Stas to be 22.87 (H = I) ; T . W .
See also:Richards and R . C .
See also:Wells (Journ . Amer . Chem . Soc., 1905, 27, p . 459) obtained, the value 23.006 (0 =16) .
See also:Medicine .
See also:Pharmacology.—The metal sodium is not used in medicine, but many of ,its salts are employed .
Besides liquor sodii ethylatis the following salts and preparations are used in the
See also:British Pharmacopoeia . (I) Sodii tarbonis, known as washing soda; this carbonate on heating yields sodii carbonis exsiccaius and sodii bicarbonas; from the, latter is made trochiscus sodii bicarbonatis . (2) Sodii phosphas . From sodium phosphate are made sodii phosphas effervescens and sodii by ophosphis (ssee PHOSPHORUS) . (3) Sodii sulphas (Glauber's salt), with its sub-preparation sodii sulphas effervescens . (4) Soda tartarata (Rochelle salt), a tartrate of sodium and potassium, from which is made pulvis sodae tartaratae effervescens, known as Seidlitz powder . (5) Sodii cilro-tartras effervescens, a mixture of
See also:sugar, sodium bicarbonate, citric and tartaric acids . (6) Sodii chloridum, common salt . (7) Sodii sulphas . For sodii bromidum, iodidum and salicylatum see BROMINE, IODINE and SALICYLIC ACID respectively . For sodii arsenas and cacodylale see ARSENIC . Sapo durus (hard soap) is a compound of sodium with
See also:olive oil, and
See also:sago animalis (curd soap) is chiefly sodium stearate .
See also:Toxicology.—Poisoning by caustic soda is rare, but occasionally it takes place by swallowing soap lees (sodium carbonate), which may contain some impurities of caustic soda . The symptoms and treatment are the same as described under POTASSIUM . The salts of sodium resemble potassium in their action on the alimentary
See also:tract, but they are much more slowly absorbed, and much less diffusible; therefore considerable amounts may reach the small
See also:intestine and there
See also:act as saline purgatives . They are slowly absorbed into the
See also:blood, and are a natural constituent of the blood plasma, which derives them from the
See also:food . Sodium is excreted by all the mucous surfaces and by the
See also:liver and kidneys . On the latter they act as diuretics, but less powerfully than potassium, increasing the flow of water and the output of
See also:urea and rendering the urine less acid . They are said to diminish the secretion of the bronchial mucous membrane . Therapeutics:
See also:External Use.—The liquor sodii ethylatis is a powerful caustic and is used to destroy small naevi and warts . A lotion of sodium bicarbonate is useful to allay itching . Solutions of sodium sulphite are used as mild antiparasitics .
See also:Internal use.—Sodium chloride 'is occasionally used in warm water as an emetic, and injections of it into the rectum as a treatment for
See also:worms . A o.9% solution forms what is termed normal saline solution, which, is frequently injected into the tissues in cases of collapse, haemorrhage and diarrhoea .
It forms a valuable treatment in diabetic
See also:coma and eclampsia, acting by diluting the toxins in the blood . From this has
See also:developed the intramuscular injection of diluted sea-water in the treatment of gastro-
See also:enteritis, anaemia and' various skin affections . Sodium chloride is an important constituent of the waters of Homburg,
See also:Nauheim and
See also:Kissingen . Sodium bicarbonate is one of our most useful gastric sedatives and antacids, relieving
See also:pain in hyperchloridia . It is the constituent of most stomachic mixtures . Effervescent soda water is a mild gastric sedative . Sodium phosphate and sulphate are cholagogue purgatives and are used in the treatment of gallstones . The sulphate is the chief constituent of
See also:Marienbad and
See also:Carlsbad waters . Large doses of these salts are used to remove fluid in
See also:dropsy . Soda tartarate is purgative and diuretic, as is the citro-tartarate . These purgative sodium salts are most useful in the treatment of chronic
See also:constipation, and of the constipation associated with
See also:gout and hepatic dyspepsia . They should be dissolved in warm water and taken in the
See also:fasting .
In visceral gout and chronic catarrhal conditions of thestomach a course of alkaline waters is distinctly beneficial . Sodium salts have not the depressant effect so marked in those of potassium .
SODOM AND GOMORRAH
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