Sodium

SODIUM (Natrium), a chemical element, symbol Na, is a silvery-white, shiny, monovalent metal with a waxy consistency at ordinary temperatures, which becomes brittle when cold and distills at a bright red heat; it was discovered by Davy (1807) through the electrolysis of molten caustic soda. Specific gravity 0.97; atomic weight 23; monovalent; melting point 97.5°; boiling point 878°. The colorless flame of a Bunsen burner is colored yellow by sodium and its compounds; sodium produces two characteristic yellow lines in the spectrum. The monovalent Na-ion (Na+) is colorless. Practically all sodium salts are soluble in water. Relatively more difficult to dissolve are sodium fluorosilicate, Na₂SiF₆, which forms upon the addition of fluorosilicic acid to a concentrated solution of any sodium salt, and the salt of antimonic acid, NaH₂SbO₄·2H₂O. Sodium is obtained either by heating sodium carbonate with carbon at a white heat (Na₂CO₃ + 2C = 2Na + 3CO) or by heating magnesium shavings with caustic soda or soda ash; the modern, more frequent method of production is the electrolysis of molten caustic soda. Metallic sodium tarnishes very quickly in ordinary moist air and becomes covered with a layer of NaOH and Na₂CO₃, which form at the expense of the H₂O and CO₂ present in the air; in completely dry air, sodium retains its luster for an indefinitely long time. When thrown into water, sodium moves energetically across the water and decomposes it; the resulting hydrogen does not ignite spontaneously; a flash occurs if the movement of the sodium is obstructed, for example, by moist filter paper. Metallic sodium alloys with many metals, forming the type of indefinite compounds called alloys. If sodium is thrown onto mercury, especially if heated, a flash occurs and such a significant release of heat takes place that part of the mercury turns into vapor. Compounds of sodium with mercury, or amalgams, represent solid bodies even at 2 parts sodium to 100 parts mercury. Amalgams are often used instead of sodium in chemical work. Metallic sodium is capable of dissolving—at low temperatures without the release of hydrogen—in liquefied ammonia, forming a blue solution. Sodium does not react at all with hydrogen at ordinary temperatures, but absorbs hydrogen at temperatures of 300–420°, forming NaH; the latter oxidizes directly in air. Sodium releases hydrogen not only from water but also from hydrogen chloride and all other acids. Closely related to this property of sodium is its ability to remove oxygen, chlorine, and similar elements from most of their compounds. With oxygen, sodium forms three degrees of compounds: suboxide Na₄O, oxide Na₂O, and peroxide Na₂O₂. The oxide is a stable basic oxide, which gives an alkali with water. The suboxide is a gray, flammable substance that decomposes water with the release of hydrogen. Sodium peroxide is a darkish substance that melts at a bright red heat. Suboxide: Na₄O + 3H₂O = 4NaOH + H₂. Oxide: Na₂O + H₂O = 2NaOH. Peroxide: Na₂O₂ + 2H₂O = 4NaOH + O₂. Sodium peroxide, by forming hydrogen peroxide with acids, acts as an oxidizing agent, similar to the latter. Sodium does not form acidic oxides; its salts are of the type NaX; consequently, in compounds, sodium is basic and monovalent, like hydrogen. In nature, sodium is very widespread, especially in the form of sodium chloride (in rock salt, in seawater, in springs), in the form of silicates, often in combination with potassium, in the form of the minerals albite (feldspar), glauberite (sodium-calcium sulfate), cryolite (sodium fluoride with aluminum fluoride), and Chile saltpeter. Sodium compounds are very widespread in the animal organism. Of the sodium salts, NaCl (see Table salt) and NaHCO₃ are especially important for the animal organism. The former plays a paramount role in regulating osmotic and diffusion processes and constitutes the main mass of the body's electrolytes; the latter takes the main part in maintaining the alkaline-acid balance and the "buffering" (see Buffer properties) of the blood and tissues. Both the Na-ion and the Cl-ion and HCO₃-ion are the most common ions in our body, with sodium salts predominating over potassium salts in the body fluids, while the reverse relationship holds in the body's cells. With a normal mixed diet, a person consumes from 10 to 15 g of NaCl per day; a reduction to 5 or even 2 g may not yet cause them any particular disorders. In nephritis, the onset of a new equilibrium usually occurs with greater slowness. The excretion of chlorides decreases significantly in some forms of nephritis, in fevers, especially in pneumonia (due to the abundant content of NaCl in pneumonic effusions), and also during the period of rapidly growing newly formed tissues (e.g., in cancer). A diet poor in chlorine promotes the retention of bromine ions in the body (salt-free diet in the treatment of epilepsy with bromides). Isotonic solutions of NaCl for the tissues of cold-blooded animals are considered to be 0.6–0.65%; for the tissues of warm-blooded animals—0.85–0.9%. Isotonic or weakly hypotonic solutions exert an insignificant (less than potassium salts) locally irritating effect; hypertonic solutions or salt in substantia, on the contrary, strongly irritate tissues due to a sharp disturbance of the osmotic relations of the tissues, however, they do not lead to gross destruction of tissues, unlike, for example, strong acids or alkalis or salts of heavy metals. In the form of salt baths, NaCl exerts an irritating effect on the skin; on mucous membranes, NaCl solutions, depending on the concentration, produce irritation of varying degrees; salt taken in strong concentrations and in large quantities can lead to phenomena of severe inflammation and to cruel gastroenteritis, which can end in death. NaCl is easily absorbed by mucous and serous membranes (but not by the skin); if the salt was taken without sufficient dilution with water, an increase in the concentration of NaCl in the tissues occurs; this causes a feeling of thirst and leads to the excretion of hypertonic urine; if, however, the salt was introduced with an abundant amount of water, then strong diuresis occurs ("salt" diuresis, which has hydremia of the blood as its main source). The amount of excreted metabolic products increases, the metabolism as a whole, it is believed, increases, in particular—gas exchange. According to Schmiedeberg's data, protein breakdown is intensified, and nitrogen excretion increases. When NaCl solutions (2.5% and higher) are introduced into the blood, glycosuria is observed in rabbits; its immediate cause has not yet been clarified; some consider glycosuria to be a consequence of increased permeability of the kidneys for sugar, others attribute its appearance to the excitation of the glycosuric center due to a disturbance of the ionic equilibrium in the nerve centers; with the simultaneous introduction of calcium salts, glycosuria does not occur. Finkelstein (1908) made the observation that in children (as well as in rabbits and guinea pigs), the introduction of NaCl subcutaneously, as well as per os, can cause a rise in temperature; in adults, a similar phenomenon was observed only with the subcutaneous introduction of at least 1 liter of 0.9% NaCl. In addition to the rise in temperature, an intensification of nitrogen metabolism and an intensification of heat production are also observed. A similar rise is produced by subcutaneous injections of dextrose, lactose, colloidal metals, and others. In the opinion of most authors, the cause of the fever is the irritation of the heat centers by chemical products formed as a result of the action of NaCl on the tissues; with the introduction of Ca salts, fever does not occur. It is accepted that one of the most important points of application of salts, or rather their ions, in the organism is their action on colloids (see Ions, physiological and colloidal action). Using the example of lecithin, it has been proven that the ability inherent in it to lower surface tension is influenced by various salts of potassium, sodium, and calcium, with an antagonism being observed in the action of different ions. The combinations most "equilibrated" in the sense of the absence of any action on the colloidal state of lecithin turned out to be 1 part NaCl : 20 parts KCl or 1 part KCl : 20 parts NaCl or NaCl : KCl : CaCl₂ in the ratio 100 : 2 : 2. In terms of the influence of salts on cellular colloids—and first of all on the colloids of the cell membrane—the indicated ratios are very important; they give a concept of "isoionia," of "physiologically equilibrated" solutions (see Potassium). As is known, an isotonic and isoionic solution (for frog tissues) is Ringer's solution (0.65% NaCl, 0.02% CaCl₂, 0.01% KCl, 0.01% NaHCO₃). If one forces a frog's heart to work in a solution of pure NaCl (0.65%), excluding other salts, then the work of the heart weakens relatively quickly; upon changing to Ringer's solution, the work of the heart is restored. When the concentration of NaCl in Ringer's solution is lowered from 0.65% to 0.1–0.2% and the lack of osmotic pressure is compensated by some non-electrolyte (grape or cane sugar), a very strong increase in the amplitude of contractions of the frog's heart is obtained; when the concentration of NaCl in Ringer's solution is increased above 0.65%, a drop in amplitudes is noticed.

If the heart was working in a sinus rhythm, then upon lowering NaCl to 0.1%, a slowing of the rhythm occurs; conversely, if the heart was working in a ventricular rhythm, then on frog hearts a strong acceleration of the rhythm was obtained, and on the hearts of warm-blooded animals, a slowing. That this is connected with the action of the Na-ion is evident from the fact that a similar phenomenon is obtained in neutral solutions of any Na salt. Furthermore, it is accepted that Na and K ions act on the heart generally in one direction, namely, diastolically, negatively inotropically and chronotropically; at the same time, K is more strongly acting. According to other data (ten Cate), the K-ion is necessary for cardiac automatism, Ca for contractility, and Na for the conductivity of cardiac tissue. Be that as it may, each of these ions by itself is harmful to the work of the heart, and only their combination is capable of providing physiological isoionia and ensuring normal work for the heart. The excitability of the cardiac vagus, as well as the indirect (via nerve) excitability of striated muscles in pure NaCl solutions, decreases and disappears; upon the introduction of Ca salts, it returns again. Upon lowering the NaCl concentration in Ringer's solution from 0.6% to 0.1%, the amplitude of contractions of the isolated frog ventricle increases, the rhythm slows; upon increasing the concentration, the opposite is observed. Furthermore, it is known that if a striated muscle of a frog is transferred into a solution of a non-electrolyte, e.g., grape or cane sugar, the muscle quickly becomes inexcitable; upon transfer into a solution of pure NaCl, excitability is restored, and spontaneous fibrillary contractions, which do not occur under normal conditions, are observed, which can be stopped by the addition of Ca salts. Direct muscular excitability, lost by the muscle from the action of K salts, is restored upon the addition of Na salts. Na salts excite the nervous apparatus of the intestines upon contact. According to Loeb, sea urchin eggs, as well as the marine fish Fundulus heteroclitus, while maintaining their viability in pure distilled water, perish upon transfer into an isotonic NaCl solution; the harmful effect of Na ions can be destroyed by the addition of even very insignificant amounts of calcium salts (see Calcium). The reflex excitability of the spinal cord, as proven by Overton on frogs and Gerlach on newborn rabbits, falls in solutions of pure NaCl, but upon changing to Ringer's solution, it is quickly restored. Regarding the action of Na salts on blood vessels, it follows from data obtained on isolated organs that the action is expressed in the dilation of vessels (both internal and peripheral organs) and depends on the cationic component (on the Na-ion), and not the anionic component of the salt (Gramenitsky); according to data obtained by Flatow and Morimoto, using the method of irrigating a limb on a whole animal (according to Schilf), hypotonic solutions of sodium chloride act in a relaxing manner; hypertonic ones give an initial constriction followed by dilation. The absorption of NaCl solutions, like most other substances, occurs mainly from the intestine and only to a very insignificant degree from the stomach. Phosphate and especially sulfate sodium salts are difficult or almost not at all absorbed by the gastrointestinal tract and, by retaining water, increase the volume of intestinal contents, irritate the local nervous apparatuses of the intestine, and therefore act as a laxative. Upon intravenous administration, sodium sulfate produces a sharp diuretic effect, stronger than sodium chloride; diuresis is accompanied by a large excretion of chlorides, which (evidently under the influence of the sulfates of the introduced salt) are mobilized from the tissues. NaCl is further important as material for the formation of HCl in the stomach; upon the exclusion of NaCl from food, the stomach ceases to secrete HCl on the 9th day (Babkin). The addition of NaCl to food increases the work of the gastric glands, which depends on the stimulating action of NaCl on the pyloric region of the stomach, from where reflex irritation is transmitted to the pepsin glands of its fundic part. The addition of NaCl in an amount of 1/2-1% to enemas with nutrient solutions promotes better absorption of the latter. The addition of stronger concentrations up to 3-5% sodium chloride enhances the action of evacuating enemas. Finally, two more experimental facts deserve mention. Thus, according to recent studies by Adlersberg and Perutz, the additional oral administration ("loading") of sodium chloride accelerates the resorption of artificial inflammatory exudates in the skin. Furthermore, according to data by Ehrismann, intracardiac administration of NaCl solutions acts no more toxically than intravenous or intra-arterial administration, in contrast to, for example, potassium salts and certain other compounds, which upon intravenous and especially intra-arterial administration are significantly less toxic than upon administration into the heart cavity. The main cases of the therapeutic use of Na salts. In the form of the so-called physiological 0.85% NaCl solution, it is used for subcutaneous and intravenous administration during a drop in blood pressure, during dehydration of the body, during intoxications, etc. Recently, solutions of a more complex composition with the addition of soda and colloidal substances are preferred, for example: NaCl 0.85%, KCl 0.02%, CaCl₂ 0.02%, MgCl₂ 0.01%, Gummi arabici 0.7%, NaHCO₃ 0.12%. In very strong solutions or in substantia (1-1 1/2 teaspoons), NaCl is used to stop pulmonary hemorrhages; intravenous injections of 3-5 cm³ of 10% NaCl act in the same way; the mechanism of action has not been clarified. It is also used for the treatment of catarrhal conditions of various mucous membranes: bronchi, gastrointestinal tract, female genital organs; the intake of NaCl, as well as Na₂SO₄, sometimes with the addition of NaHCO₃, e.g., in the form of mineral waters, finds wide application. Na₂SO₄ and mineral waters containing it are used as laxatives. Iso- and hypotonic NaCl solutions have a diuretic effect. Thanks to diuresis and the washing out of metabolic products from tissues, treatment with common salt waters proves useful in various metabolic diseases—gout, obesity, in the lowering of oxidative processes, in various kinds of chronic inflammations. The use of common salt in the form of baths and showers at 34-35° on the skin, thanks to reflex influences on distant organs, has proven useful in the treatment of various chronic inflammations, in the asthenic state of the nervous system, etc., for enhancing metabolism, for "training" the cardiovascular system. Baths with an indifferent temperature (35-37°), without affecting general metabolism, act in a calming manner on the nervous system and lower blood pressure (Lavrov). Common salt and sodium bicarbonate are often used for gargles, irrigations, and inhalations. Finally, it can be mentioned that the use of NaCl solutions is an antidote for AgNO₃ poisoning. Preparations. Natrium bicarbonicum, sodium bicarbonate salt, sodium bicarbonate, NaHCO₃; white crystalline aggregates, dissolving in approximately twelve parts of water, with the formation of a solution of weakly alkaline reaction. Per os in decigrams, for inhalations—in 0.1-1% solutions, for gastric lavage—in 1-2% solutions. It is often used, especially in the form of alkaline therapeutic mineral waters, for chronic and subacute catarrhs of the stomach and respiratory tract, for catarrh of the bile ducts, for metabolic diseases, general obesity, diabetes mellitus, uric acid diathesis; in coma diabeticum, very large amounts are introduced—up to 30.0-60.0 per day. It is used in the form of powders and solutions. Natrium carbonicum crystallisatum depuratum, Na₂CO₃+10H₂O; purified sodium carbonate salt, purified soda; colorless, transparent crystals that effloresce in air, dissolving in 1.6 parts of cold and in 0.2 parts of boiling water, insoluble in alcohol. Aqueous solutions of the salt have a strongly alkaline reaction. It is rarely used internally, as it irritates the gastric mucosa. It is often used for external skin washings for the purpose of softening it, for removing hypertrophied layers, for example in eczema, psoriasis, etc. For baths, 1-3 kg of (unpurified) soda is taken per bath for an adult. Natrium chloratum, NaCl, sodium chloride, common salt; white crystalline powder; dissolves in 2.7 parts of water, forming a colorless solution of neutral reaction. Internally in doses of 0.3-1.0 several times a day. In chronic catarrhal diseases of the respiratory tract, treatment with "weak" (no more than 15 g per 1 liter of water) NaCl mineral waters or inhalation of atomized NaCl solutions is prescribed. In chronic catarrh of the stomach and intestines, in their atony, in catarrhal jaundice, in congestion in the portal vein region, the drinking of "weak" NaCl mineral waters has wide distribution. The use of strong therapeutic natural NaCl waters in the form of baths, rubdowns, poultices, sea bathing, etc., finds its place in the treatment of anemia, scrofula, rickets, chronic skin diseases, muscular and articular rheumatism, neuralgias, perimetritis, etc.

In cases of acute blood loss and a drop in blood pressure, as well as in uremia and cholera, subcutaneous or intravenous infusions of 0.9% NaCl in amounts of 0.5-1 liter or more are prescribed. In cases of pulmonary hemoptysis, 1-3 teaspoons of NaCl per os with a small amount of water sometimes provide benefit. - Natrium sulfuricum; Na₂SO₄ + 10H₂O, sodium sulfate, or Glauber's salt; colorless, transparent, efflorescent crystals, soluble in 3 parts cold and 0.4 parts boiling water, insoluble in alcohol. It is used as a laxative - 15.0-30.0 per 1-2 glasses of water or in the form of alkaline-Glauber's and bitter medicinal waters, especially for chronic constipation in well-nourished, obese people leading a sedentary lifestyle. Na₂SO₄ is an appropriate antidote for poisoning with barium chloride and soluble lead compounds. - Among other sodium salts, which act primarily through their anion, one may mention Natrium benzoicum, boracicum, bromatum, kakodylicum, jodatum, nitricum, nitrosum, phosphoricum, salicylicum, sulfurosum.