Sodium (Na), the chemical element of the alkaline metal group (group 1 [Ia]) of the periodic table. Sodium is a very soft white metal. Sodium is the most common alkali metal and the sixth most abundant element on Earth, accounting for 2.8% of the Earth's crust. It is found abundantly in nature in compounds, especially the common salt - sodium chloride (NaCl) - which forms the mineral halite and makes up about 80% of the dissolved components of seawater.
Sodium
Element properties
Atomic number 11
Atomic weight 22.9898
Melting point 97.81 ° C (208 ° F)
Boiling point 882.9 C (1,621 F)
Specific gravity 0.971 (20 C)
Oxidation conditions +1, −1 (rare)
Electron configuration 2-8-1 or 1s22s22p63s1
Features and production
Because sodium is highly reactive, it is never released into the earth's crust. In 1807, Sir Humphrey Dewey became the first person to develop an early form of sodium, applying electrolysis to fused sodium hydroxide (NaOH). Sodium is an important component of many silicate materials, such as field sparse and macas. Large deposits of rock salt are found in different parts of the world, and sodium nitrate deposits are present in Chile and Peru. The ocean sodium content is about 1.05%, which is equivalent to a concentration of about 3% sodium halides. Sodium has been identified in the star spectra in both atomic and ionic forms, including the Sun, and interstellar medium. Analysis of meteorites shows that the silicate material present has an average content of about 4.6 atoms for every 100 atoms of silicon.
Sir Humphrey Dewey
Description of Oil Painting after Sir Humphrey Dewey, Sir Thomas Lawrence; At the National Portrait Gallery, London.
Courtesy National Portrait Gallery, London
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Lighter than water, sodium can be cut with a knife at room temperature but broken down at low temperatures. It easily conducts heat and electricity and reflects the photoelectric effect (emission of electrons when exposed to light) to a significant degree.
Sodium is by far the most commercially important alkali metal. Most processes for sodium production involve electrolysis of molten sodium chloride. Cheap and available in tank car quantities, this element is used to produce gasoline, polymers such as nylon and synthetic rubber, pharmaceuticals, and various metals such as tantalum, titanium, and silicon. It is also widely used as a heat exchanger and in sodium vapor lamps. The yellow color of the sodium vapor lamp and the sodium flame (the basis of the analytical test for sodium) are identified by two prominent lines in the yellow part of the spectrum of light.
High Pressure Sodium Vapor Lamp Bulb.
(Above and between) W.H. Rhodes and GC R.W. Weaver (eds.) In Cahn and M.B., Encyclopedia of Materials Science and Engineering, Supplementary Vol. 3, © 1993 Pergamon Press (Below) General Electric Company
Important use
The first two uses of metallic sodium were in the manufacture of sodium cyanide and sodium peroxide. Significant quantities were used in the manufacture of tetraethyl lead as an addition to gasoline, a market that disappeared with the advent of unleaded gasoline. Large amounts of sodium are used in the manufacture of sodium alkyl sulfate as a main ingredient in synthetic soaps.
Sodium is also used as a starting material in the preparation of sodium hydride (NaH) and sodium borohydride (NaBH4). In addition, sodium is used in the preparation of dyes and dye intermediates, in the synthesis of perfumes, and in a wide variety of organic reduction. It is used in hydrocarbon purification and polymerization of unsaturated hydrocarbons. In many organic applications, sodium is used as a dispersion in hydrocarbon liquid media.
Molten sodium is an excellent heat transfer fluid, and, because of this property, it has been used as a coolant in liquid metal fast breeder reactors. Sodium is widely used in metallurgy as an oxidant and as a reducing agent in the manufacture of calcium, zirconium, titanium, and other transition metals. Commercial production of titanium involves the reduction of titanium tetrachloride (TiCl4) with sodium. The products are metal Ti and NaCl.
Principal compounds
Sodium is highly reactive, forming a wide variety of compounds with almost all inorganic and organic ions (negatively charged ions). It usually has an oxidation state of +1, and its single valence electron is easily lost, resulting in colorless sodium cation (Na +). Compounds containing sodium anion, Na−, have also been synthesized. The principal commercial sodium compounds are chloride, carbonate, and sulfate.
The most important and familiar sodium compound is sodium chloride, or common salt, NaCl. Most other sodium compounds are made directly or indirectly from sodium chloride, which is found in seawater, natural salts, and rock salts. Large amounts of sodium chloride are used in the manufacture of other heavy (industrial) chemicals as well as in direct ice and snow removal, water conditioning and food.
Sodium chloride
Sodium chloride.
Henningklevjer
Other major commercial uses of sodium chloride include its use in the preparation of chlorine and sodium hydroxide by electrolytic decomposition and in the preparation of sodium carbonate (Na2CO3) by the solute process. Electrolysis of aqueous sodium chloride produces a mixture of sodium hypochlorite, NaOCl, sodium, oxygen, and chlorine, which is used in large quantities in household chlorine bleach. Sodium hypochlorite is also used as an industrial bleach for paper pulp and textiles, for water chlorination, and as a disinfectant and fungicide in some medicinal preparations. It is an unstable compound known only in water solution.
Carbonate contains carbonate ion (CO32–). Sodium bicarbonate, also called sodium hydrogen carbonate, or soda bicarbonate, NaHCO3, is a source of carbon dioxide as well as in baking powder, in salts and beverages, and as an important ingredient in dry chemical fire extinguishers. Is used as . Its mild alkalinity makes it useful in treating gastric or uric acidity and acidity. It is also used in some industrial processes, such as in tanning and wool manufacturing. Sodium carbonate, or soda ash, Na2CO3, is widely distributed in nature, as mineral water constituents and solid minerals as neutrons, tranna, and thermonitrite. Large amounts of this alkaline salt are used in making glasses, detergents and cleansers. Sodium carbonate is treated with carbon dioxide to produce sodium bicarbonate. The monohydrate form of sodium carbonate, Na2CO3 · H2O, is widely used by developers as a component in photography.
Sodium bicarbonate
Sodium bicarbonate (NaHCO3), also called baking soda or soda bicarbonate. Baking soda is a type of fermenting agent used in baking.
Sodium sulfate, Na2SO4, is a white crystalline solid or powder used in the manufacture of kraft paper, paperboard, glass and detergents, and as a raw material for the manufacture of various chemicals. It is obtained either from the deposits of sodium sulfate minerals merabilite and thenardite or by synthetic treatment of sodium chloride with sulfuric acid. The crystallized product is a hydrate, Na2SO4 · 10H2O, commonly known as Globers salt. Sodium thio sulfate (sodium hypo sulfite), Na2S2O3, is used by photographers to correct negatives and prints. It works by melting the part of the silver coated coating on the film that does not change when exposed to light.
Sodium hydroxide (NaOH) is a corrosive white crystalline solid that absorbs moisture easily until it dissolves. Caustic soda, or lye, sodium hydroxide is the most widely used industrial alkali. It is highly corrosive to animal and vegetable tissues. When dissolved in water, the alkaline solution neutralizes the acid in various commercial processes: in petroleum refining, it removes sulfur and organic acids. In soap making, it reacts with fatty acids. NaOH solutions are used in the treatment of cellulose and in the manufacture of many chemicals.
Vaporizer
Falling film vapor for a concentrated solution of caustic soda (sodium hydroxide).
Robin Castelnovo
Sodium nitrate, or soda nitrate, NaNO3, after its mineral deposits in northern Chile, is commonly called Chilean salt petri, which is the primary source. Sodium nitrate is used as nitrogen fertilizer and as a component of dynamite.
Chemical properties
In general, elemental sodium is more reactive than lithium, and it reacts with water to form a strong base, sodium hydroxide (NaOH). Its chemistry has been well discovered.
Reaction with air, water and hydrogen
Sodium is generally highly reactive with air, and the reaction is a function of the relative humidity, or water vapor content of the air. The corrosion of solid sodium by oxygen is also accelerated by the presence of a small amount of impurities in the sodium. In normal air, sodium metal reacts to form a sodium hydroxide film, which rapidly absorbs carbon dioxide from the air to form sodium bicarbonate. Sodium does not react with nitrogen, so sodium is usually immersed in a nitrogen environment (or in inert liquids such as kerosene or naphtha). It reacts significantly more in the air as a liquid than a solid, and the liquid can ignite at about 125 ° C (257 ° F). In a relatively dry environment, sodium burns quietly, emitting a thick white caustic smoke, which can cause suffocation and coughing. The temperature of burning sodium rises faster than 800 ° C (1,500 F), making fires extremely difficult to extinguish. Special dry powder fire extinguishers are required, as sodium reacts with carbon dioxide, a common propellant in regular fire extinguishers.
Sodium monoxide (Na2O) is usually formed by the oxidation of sodium in dry air. Superoxide (NaO2) can be prepared by heating metallic sodium to 300 ° C (570 ° F) to contain oxygen at high pressure in an autoclave (a hot-pressed vessel). Another form of superoxide is the oxidation of sodium peroxide, Na2O2, which is treated for surface area enlargement.
Sodium, which is highly contaminated with monoxide, can be easily removed by filtration, as molten sodium has a lower solubility of oxide. This low solubility is widely used in the continuous purification of sodium in large liquid metal reactor systems. Another technique of oxide removal, called cold trapping, involves moving the molten sodium through a cold-packed bed of material, which can accelerate the oxide. Filtration and cold trapping are also effective in removing the total amount of carbonate, hydroxide and hydride.
Reaction of liquid sodium with high levels of water can be explosive. Sodium water reacts with extreme external heat (ie heat is removed):
However, tests have shown that sodium and water cannot be mixed so fast that they can produce shock waves characteristic of more explosives. Explosive hazards of the reaction are mainly related to the formation of hydrogen gas.
Pure sodium begins to absorb hydrogen at approximately 100 ° C (212 ° F); The rate of absorption increases with temperature. Pure sodium hydride can be made by exposing sodium to hydrogen gas at temperatures above 350 ° C (660 ° F) at high flow rates. The degradation of sodium hydride is much higher than that of lithium hydride to produce hydrogen and molten sodium at higher temperatures, but slightly lower than that of potassium hydride.
Reaction with non-metals
In general, alkali metals react with halogen gases, the degree of reaction decreases with the increase in the atomic weight of halogen. Sodium is no exception. Under certain conditions of reaction, sodium and halogen vapors react to produce light (chameleonism). Halogenic acids, such as hydrochloric acid, react with sodium to form sodium halides. For reactions of hydrofluoric and hydrochloric acids with reaction reactions (energized) of −71.8 and −76.2 kcal, respectively, the reactions are highly external heating. Other strong mineral acids attack sodium to form related salts. It reacts with nitric acid fumes at 15 ° C (59 ° F) to form sodium nitrate and reacts with acetic and sulfuric acid to form sodium acetate and sodium sulfate. With molten sulfur it reacts violently to produce polysulfides. Under highly controlled conditions, it reacts with organic solution of sulfur. Both liquid selenium and tellurium react strongly with solid sodium to form selenides and telllorides.
Sodium reacts relatively less with carbon, although lamellar (layered) materials can be produced that contain sodium between layers of graphite. Carbon monoxide reacts with sodium at 625 ° C (1,157 F) to form sodium carbide and sodium carbonate.
With the exception of oxides of group 4 (IVb) metals (titanium, zirconium, and hafnium), oxides of transition metals are reduced to the corresponding metals containing elemental sodium. Sodium also reacts with a large number of metal halides, removes the metal from the salt and in the process forms sodium halides. This reaction itself is used in the manufacture of many transfer metals, including titanium and tantalum.
Sodium and all other alkali metals dissolve in liquid ammonia to form intense blue solutions, and at normal temperatures a slow reaction between sodium and ammonia results in the formation of sodium, NaNH2 and hydrogen, as with water. The reaction is to give NaOH and the hydrogen reactions are:
Na + NH3 → NaNH2 + 1/2 H2
Na + H2O → NaOH + 1/2 H2
The reaction of the alkali metal ammonia solution to form amides and hydrogen can be catalyzed by the addition of many metals and metal oxides.
Liquid ammonia is often used as a solvent for sodium, causing a number of reactions at normal temperatures that would otherwise require heat. Sodium superoxide (NaO2), for example, can be formed by transferring oxygen through ammonia solution of sodium at 777 ° C (−107 ° F). Ammonia also acts as a solvent for the reaction of sodium with arsenic, tellurium, antimony, bismuth and other molten metals. Sodium ammonia solution is used to blacken polytetrafluoroethylene (Teflon) to prepare its surface for cementing with other materials. The high reducing power of sodium ammonia solution makes them useful in a number of organic reactions called birch reductions.
Organic reactions
The organic reaction of sodium has been studied to a greater extent than that of other alkali metals. Sodium anhydrous reacts with alcohols to form the corresponding alcohol (or alkoxide).
Na + ROH → RONa + 1/2 H2,
R is the organic component of alcohol (R = CH3 for methanol, CH3CH2 for ethanol, etc.). The reaction is most intense with methanol and decreases with increasing molecular weight of alcohol. Sodium methane oxide is produced on an industrial scale by the reaction of sodium methanol. Organic acids react with sodium to form sodium salts.
The large negative free energy of the formation of sodium halides allows the delogenation of many organic halides, the composition of sodium halides being preferred with energy. The so-called Wurtz reaction - based on this principle - is largely used in organic synthesis:
2RCl + 2Na → R ― R + 2NaCl.
By this reaction, octane can be made from bromobutine and sodium. Organosodium compounds contain a number in which the sodium atom is directly attached to the carbon atom. An example is methylsodium, Na-CH3. Such compounds can be produced by the action of sodium on mercury dialcells or dials, as in the following equations:
Hg (CH3) 2 + 2Na → 2NaCH3 + Hg.
Sodium reacts violently with multiple halogenated hydrocarbons. For example, a violent explosion occurs when a mixture of carbon tetrachloride and sodium is shaken. Even when sodium is significantly diluted - as in sodium amalgam - there is a rapid reaction with carbon tetrachloride.
Reaction with metals
Sodium is completely wrong with the alkaline metals below it in the periodic table (potassium, rubidium, and cesium). At 10 ° C (14 ° F) the eutectic (ie, a compound that dissolves less than its constituents) is formed in the sodium potassium system and is commercially known as NaK. Its composition is about 78% potassium, and it is used as a heat transfer fluid and as an organic reactant. Eutaxes formed in sodium-rubidium and sodium-cesium binary systems melt at −4.5 and −30 ° C (24 and −22 ° F, respectively). Sodium is a minor component of ternary NaKCs with potassium and cesium, which melts at −78 ° C (−108 ° F). This fluid is the least soluble liquid compound yet isolated.
Sodium alkaline also forms alloys with earth metals. At about 800 ° C (1,500 ° F), beryllium is soluble in sodium only a few atoms percent. Liquid sodium and magnesium are only partially differentiated. The degree of solubility in the sodium of alkaline earth metals increases with increasing atomic weight, resulting in a calcium solubility of 10% by weight at 700 ° C (1,300 ° F). There is a lot of misunderstanding in the sodium strontium system. Sodium forms many compounds with barium, and there are many eutectics in the system.
Precious metals, such as silver, gold, platinum, palladium, and iridium, and white metals, such as lead, tin, bismuth, and antimony, are admirably mixed with liquid sodium. Cadmium and mercury also react with sodium, and both binary systems contain several compounds. There are seven sodium mercury compounds, or amalgams, with Hg2Na having the highest melting point (354 ° C, or 669 ° F). Sodium amalgamus is used to react, especially in situations where it is difficult to react violently to pure elemental sodium and difficult to control. The solubility of transfer metals in alkali metals is generally very low, often in the range of 1–10 parts per million, even at temperatures above 500 ° C (930 ° F).
Atomic properties
Natural sodium mass 23 is a stable isotope. Of the radioactive synthetic isotopes, sodium-22 (2.6-year half-life, the longest half-life of the sodium isotope) is used as the radioactive tracer for natural sodium. Sodium 24 (half-life of 15 hours) is limited in use due to its short life and is produced by radiation in a nuclear reactor. Because of this reaction, the sodium cooler reactor must have a second heat transfer loop so that the radioactive sodium does not come into contact with the atmosphere. Other isotopes have a half-life of one minute or less.
Biological features
Sodium salts, especially sodium chloride, are found almost everywhere in biological materials. Sodium is an essential element for life, as is potassium, and both elements maintain a certain balance in cell structure. The electrolyte balance between inside and outside the cell is maintained by the "active transport" of potassium ions in the cell and by the sodium ions outside the cell. While most biological effects of sodium salts are due to cation (Na +), negative anti-ions do not seem to play a major role.
The presence of salts in the soil is often detrimental to plant growth. Sodium ions convert calcium and other ions into soil compounds, transforming soil into viscous mass. After that, the flow of water decreases considerably, and the soil's potency increases significantly.
Fish tolerance for changes in salinity is often significant. Many marine bacteria and diatoms can tolerate up to 25% salt content. The minimum sodium requirement for mammals appears to be 0.05% of the diet, which is equivalent to the daily requirement of 1–2 grams (0.04–0.07 ounces) of salt in a normal adult, resulting in body tissues. I have an average amount of sodium. Sodium levels vary widely in 0.24% of different tissues, about 0.62% in whole blood sodium chloride, and less than 0.1% in the skin. There is a relationship between salt intake and body water balance. Low salt intake causes dehydration. Significant amounts of sodium are lost through the skin through sweating, and large amounts can be excreted in the urine.
