When Ba(OH)2 is dissolved in water, a colorless solution with a strongly alkaline reaction is obtained - barite water, which in the presence of carbon dioxide is quickly covered with a surface film of barium carbonate.
The crystalline hydrates Ba(OH)2*8H2O, Ba(OH)2*7H2O, Ba(OH)2H2O and Ba(OH)2*H2O are known. Crystal hydrate Ba(OH)2*8H2O is released in the form of colorless monoclinic prisms with a density of 2.18 g/cm3, etc. 78°. When heated to 650° in a stream of air, the crystalline hydrate turns into barium oxide or peroxide.
Passing chlorine through barite water is accompanied by the formation of chloride, chlorate and very small amounts of barium chlorite:
6Ba(OH)2 + 6CL2 = 5BaCl2 + Ba(ClO3)2 + 6H2O
Barite water reacts at 100° with carbon disulfide:
2Ba(OH)2 + CS2 = BaCO3 + Ba(HS)2 + H2O
Metallic aluminum reacts with barite water to form barium and hydrogen hydroxyaluminate:
2Al + Ba(OH)2 + 10H2O = Ba2+3H2
Above 1000°, barium hydroxide undergoes thermal dissociation:
Ba(OH)2 → BaO + H2O
Barite water Ba(OH)2 is used as a very sensitive chemical reagent for carbon dioxide.
Barium fluoride, BaF2, is obtained by direct synthesis from the elements, the action of hydrogen fluoride on the oxide, hydroxide, carbonate or chloride of barium, the treatment of barite water with hydrofluoric acid, the treatment of barium nitrate or chloride with sodium or potassium fluoride, and the fusion of magnesium chloride with calcium or magnesium fluoride in a CO2 atmosphere and thermal decomposition of barium hexafluorosilicate in an inert gas atmosphere.
Colorless cubic crystals of BaF2 have a CaF2 type lattice with a distance between the center of the Ba2+ ion and the F ion of 2.68 A. Density 4.83 g/cm3, m.p. 1280°, bp. 2137°. The crystals are slightly soluble in water (1.63 g/l at 18°C), soluble in hydrofluoric, hydrochloric and nitric acids. Used for the manufacture of enamels and optical glasses. The melting point of the BaF2*LiF mixture is 850°, and the BaF2*BaCl2 mixture is 1010°.
OBTAINING BARIUM TITOnate
Barium titanate is understood as a compound BaO-TiO2, in which the ratio of cations and anions can be different from BaTiO3 to Ba6Ti17O40, intermediate substances - polycables - are non-stoichlometric and substances that partially replace Ba and Ti can be added to them, that is, doping is carried out.
BaTiO3 has an uneven structure, but with a cubic facet or body-centered crystal lattice. The cubic structure is characteristic up to 120 °C.
At lower temperatures, the structure becomes distorted, it becomes tyragonal, and deformation of the oxygen sublattice occurs, as Ti shifts slightly.
Deformation causes polarization. For an ion, there are 2 energetically equilibrium stable positions, symmetrical relative to the center. The direction of polarization is uniform within the domain, since polarization occurs without an external... field, it is spontaneous. External stress causes ordering of the orientation of the dipoles. Hysteresis occurs between polarization and field strength.
At T>120°C=Tc, the ferroelectric properties disappear due to the height of the symmetry of the crystal (cubic structure). At T>Tc, the dielectric constant Er depends on the temperature of the Curie-Wates position
Good unligated BaTiO3 substances are dielectrics. C D E~ 3Ev. And the type of activation energy of docors is 0.1 Ev. That is, at nominal temperature these carriers are completely ionized. In addition to alloyed elements, the role of a donor is played by oxygen variations in oxygen mstechlometry due to the report.
s =rBaTiO3-1»10ohm-1m-1
From REDS and Hall
Thus, part of the impurity is of an acceptor nature. Acceptors capture electrons and a negative surface charge is created on the surface of the crystallite. A negative surface charge causes an increase in the electrostatic potential at the grain boundary. Specific conductivity depends on the height of the potential barrier. As temperature increases, conductivity increases. To maintain the electrical neutrality of the sample, a positive space charge arises in the near-surface layer of the crystal. In that layer, thickness S, there are few mobile charge carriers and density. The spatial charge is determined almost exclusively by the donor dopant nD
There are no acceptors inside the crystal that can compensate for donors.
If A is the area of the near-surface region with depth “S”, then
r*A*S – border “+” HP
N’a – concentration of acceptors that captured electrons, SCR charge “-” e* N’a
According to the condition of neutrality
r*A*S- e* N’а=0 ® S==
According to the Poisson equation, the PZ potential
Dj =-r /(x r*x 0) since r=e*nд, a*x? S
j 0=(e/(2*nd*x r*x 0))*(N’a/A)^2
b is a constant associated with N’a According to the resulting equation, R increases with increasing temperature.
In a certain temperature range, since at high temperatures Na decreases due to the release of electrons from grains trapped along the boundaries.
Use of barium titonate in radio electronics
A special place among semiconductor devices with aR>0 is occupied by devices based on barium tinanate BaTiO3. In the ΔT range 100 – 150 K they have a very high TCR, up to 0.3 K-1. Thermistors with positive temperature coefficient of resistance - PTC - thermistors-posistors.
aR=>0 – TKS.
Thermistors with a>0 are called RTS thermistors or posistors. TKS>0 has most metals and some polycrystalline materials
Ceramic posistors have TCR>0 in a narrow temperature range. Outside this range their TKS<0, как у обычных полупроводников.
List of sources used
1. Lokshin E.P., Voskoboynikov N.B. Barium. – Barium and its properties, published by KSC RAS. - 1996 - 168 p.
2. Lebedev V.N., Lokshin E.P., Masloboev V.A., Dozorova R.B., Mikhlin E.B. Raw materials sources of metals in Russia and problems of their involvement in processing // Non-ferrous metals. - 1997. - No. 8. - P.46-50.
3. Gutsol A.F. Barium titonate // Uspekhi physics. Sci. - 1997. - T.167. - No. 6. - P.165-187.
BARIUM COMPOUNDS, in accordance with the position of barium in the alkaline earth subgroup of group II of the Mendeleev system, have a doubly charged Ba ∙∙ ion (except for barium peroxide BaO 2). Barium compounds are characterized by a high specific gravity, colorlessness if the anions are not colored, a green flame color and a small number of complex compounds. Technically, the most important are oxide and peroxide, insoluble salts: barium carbonate, sulfate and chromate, and soluble salts: barium nitrate, barium chloride, etc. Soluble barium salts are poisonous. Barium is determined quantitatively in the form of BaSO 4 , but due to the extreme fineness of the precipitation obtained at low temperatures, it is necessary to precipitate from a boiling solution slightly acidified with hydrochloric acid. If there is nitric acid in the solution, part of the precipitate goes into solution. In addition, the BaSO 4 precipitate may entrain some of the salts due to adsorption. To separate it from strontium, barium is precipitated in the form of BaSiF 6 . If barium compounds are insoluble, then they are fused with potassium-sodium carbonate and, after washing the alloy with water, dissolved in acid. Barium compounds are most often found as the mineral barite; much less common is witherite - barium carbonate.
Barium oxide BaO- white solid, crystallizes in cubes, density 5.72-5.32, melting point 1580°, forms a crystalline hydrate according to the formula:
BaO + 9H 2 O = Ba(OH)2 ∙ 8H 2 O.
Barium oxide is relatively highly soluble: at 0° - 1.5 parts in 100 parts of water; at 10° - 2.2 hours, at 15° - 2.89 hours, at 20° - 3.48 hours, at 50° - 11.75 hours, at 80° - 90.77 hours. Oxide barium is obtained from barium nitrate by calcination; this produces a porous product suitable for making peroxide from it. Heating is carried out in crucibles in a muffle furnace, very carefully at first so that the crucibles do not burst. The release of nitrogen oxides begins after 4 hours, but to completely remove them, the crucibles are heated for several hours at white heat (30% of nitrogen oxides can be used to produce nitric acid). The product is very expensive, because expensive: starting material, crucibles, which are only suitable for one time, fuel, etc. Extraction of barium oxide (BaCO 3 = BaO + CO 2) from witherite is much more difficult than burning lime, t because the reverse addition of CO 2 occurs very easily; Therefore, coal is mixed with witherite so that CO 2 turns into CO. If it is desired to obtain a porous product, then the firing temperature must be strictly adhered to. To prevent sintering, barium nitrate, coal, tar or barium carbide are often added, i.e.
BaCO 3 + Ba(NO 3) 2 + 2C = 2BaO+ 2NO 2 + 3CO
ZBaCO 3 + BaC 2 = 4BaO + 5CO.
In addition, it is necessary to protect the product as much as possible from sintering with the walls of the crucible and from the influence of hot gases. Calcination in shaft furnaces produces a very pure product (95%) if the furnace is built from high quality material and heated by generator gas, which allows precise temperature control. In Italy, heating is used in electric furnaces, but apparently this produces “oxycarbide” and “barium”, which, in addition to 80-85% barium oxide, contains 10-12% carbide and 3-5% barium cyanide.
Hydrous barium oxide, caustic barite Ba(OH) 2 , forms transparent monoclinic crystals
Ba(OH) 2 ∙ 8H 2 0,
losing the last molecule of water only at dark red heat; When heated with light red heat, BaO is obtained, and when heated in a stream of air, barium peroxide is obtained. A solution of caustic barium - a strong alkali - absorbs CO 2 from the air, forming insoluble CaCO 3. 100 g of solution contains: at 0° - 1.48 g BaO, at 10° - 2.17, at 15° - 2.89, at 20° - 3.36, at 50° - 10.5, at 80 ° - 4.76. Caustic barite is used to absorb CO 2, extract caustic alkalis from sulfuric acids, extract sugar from molasses, etc. Caustic barite can be obtained by calcining witherite by passing water steam, but it is easier to burn BaCO 3 and act on BaO with water; or a mixture of 60% BaO and 40% BaS, obtained by calcining BaSO 4 with coal, is dissolved in water, and Ba(OH) 2 is obtained not only from BaO, but also from a significant part of BaS due to hydrolysis:
2BaS + 2HOH = Ba(OH) 2 + Ba(SH) 2.
The crystallized substance contains only 1% impurities. The old methods of adding iron or zinc oxides to BaS are no longer used. It is also proposed to obtain caustic barite by electrolysis of barium chloride or barium perchlorate and barium chloride in the presence of a BaCO 3 precipitate, which is dissolved by the acid formed at the anode.
Barium peroxide BaO 2 - white, pearl-like aggregates of tiny crystals, very slightly soluble in water (only 0.168 parts in 100 parts of water). To obtain peroxide, barium oxide is heated in inclined pipes or in special muffles, which can be precisely kept at the desired temperature (500-600°), and air purified from CO 2 and moisture is pumped in. The purest peroxide is obtained in the form of square crystals of BaO 2 ∙ 8H 2 O, for which they first grind technical peroxide with water, transfer it into solution by adding weak hydrochloric acid and precipitate it with a solution of caustic barite or simply add 10 times more quantity of 8% barite solution . The purest peroxide is a grayish-greenish sintered mass, insoluble in water, but reacts with carbonic anhydride. When heated, BaO 2 decomposes into BaO and oxygen. The elasticity of oxygen over BaO 2 at 555° is 25 mm, at 790° - 670 mm. Peroxide powder may cause fibrous materials to ignite. On sale there are: the best variety - with 90% BaO 2 and the average - with 80-85%, with the main impurity being BaO. The BaO 2 content is determined by titrating a 1/10 N KMnO 4 solution of BaO 2 in very weak cold hydrochloric acid (specific gravity 1.01-1.05), having previously precipitated barium ions with weak sulfuric acid. You can also titrate barium peroxide isolated from potassium iodide with sodium iodide. Barium peroxide is used to produce hydrogen peroxide (and at the same time, stronger white "Blanfix" is obtained) and for the preparation of disinfectants.
Barium nitrate Ba(NO 2) 2 ∙ H 2 O - hexagonal colorless hexagonal prisms, melting point 220°. At 0°, 58 parts of water dissolve in 100 parts, at 35° - 97 hours. It is obtained by adding a solution of sodium nitrate (360 parts of 96% NaNO 2 in 1000 parts of water) into a mixture of 360 parts of NaNO 2 and 610 hours BaCl 2 . At high temperatures, NaCl crystallizes, with further cooling - Ba(NO 2) 2.
Barium nitrate Ba(NO 3) 2 - colorless transparent octahedra, melt at 375°; in 100 parts of water, it is soluble at 10° - 7 hours, at 20° - 9.2 hours, at 100° - 32.2 hours. When heated, it turns first into barium nitrate, and then into barium oxide. Used: 1) for the preparation of barium peroxide, 2) for green lights in fireworks, 3) for some explosives. It is obtained: 1) by exchange decomposition when adding a theoretical amount of sodium nitrate to a hot solution of barium chloride (30° Ве) and subsequent recrystallization, 2) by the interaction of witherite or barium sulfide with nitric acid, 3) by heating calcium nitrate with commercial barium carbonate.
Barium permanganate - manganese greens, Kassel greens, rosenstiel greens. BaMnO 4 - durable green paint, suitable for fresco painting; is obtained by calcining a mixture of barium compounds (caustic barite, barium nitrate or barium peroxide) and manganese (dioxide or oxide).
Barium sulfide BaS - a grayish porous mass that easily oxidizes and attracts carbonic anhydride and water; decomposes with water. It is used for the manufacture of most barium compounds (lithopone, strong white, etc.), for isolating sugar from molasses and removing wool from skins (depilatory). For mining, they use calcination of a mixture of heavy spar and coal at 600-800°:
BaSO4 + 2C = 2CO2+BaS,
whereas at a higher temperature twice as much coal is wasted. The main condition is the close contact of coal and spar, which is achieved by grinding spar with 30-37% coal and water in rotating mills. Firing is carried out in rotary kilns, similar to those used for cement or soda production, and a dust chamber must be placed behind the short kilns to allow smoke and soot to settle. The resulting product contains 60-70% substances soluble in water, 20-25% soluble in acids and 5% residue. The resulting hot product is thrown into water or into an aqueous solution of 1-2% NaOH (36° Ве), where half turns into aqueous Ba(OH)2 oxide, and the other into hydrosulphurous Ba(SH)2. This solution is used directly for the preparation of barium compounds (lithopone, etc.) or for the extraction of sugar. When the residue reacts with hydrochloric acid, barium chloride is obtained. In old-type factories, calcination is carried out in fireclay retorts, uniformly engulfed in flame. Well-dried slabs of coal and spar mixed with water are loaded into the retorts. As soon as the flames of burning carbon monoxide disappear, the slabs are removed so that they fall into hermetically sealed iron boxes.
Barium sulphate BaS 2 O 3 ∙ H 2 O is formed from barium sulfide: 1) with free access of air and 2) during exchange decomposition with sodium sulfate. Used to establish titers during iodometry.
Barium sulfate BaSO 4 , heavy spar (“strong”, “mineral”, “new”, etc. white), pure white, earthy, very heavy powder, practically insoluble in water and acids (solubility: at 18° in 1 liter of water - 2 .3 mg). Natural directly grind. The best colorless varieties are called "flower" spar; ultramarine is added to yellowish and pinkish ones. Sometimes heavy spar is ground and heated with hydrochloric acid to remove iron; or spar is fused with Na 2 SO 4 and separated from the alloy by the action of water. Artificially it is obtained: 1) as waste during the preparation of hydrogen peroxide; 2) from barium chloride by interaction: a) with sulfuric acid, which gives a rapidly precipitating precipitate, b) with sodium sulfur Na 2 SO 4 or with magnesium sulfur salt MgSO 4, which gives a slowly falling powder with high covering power; During production, it is important to wash the sulfuric acid clean; 3) from witherite; if it is very pure, it can be crushed directly by the action of H 2 SO 4, but with the addition of 2% HCl; if witherite contains impurities, it is first dissolved in hydrochloric acid and then precipitated. Barium sulfate is used in Ch. arr. for coloring colored wallpaper paper, cardboard and especially for photographic papers, for light oil paints and coal varnish paints, in the manufacture of artificial ivory and rubber, for mixing with food introduced into the stomach during radiography.
Barium carbonate BaCO 3 - mineral witherite (rhombic crystals) or artificially obtained in the form of minute sediment (specific gravity 4.3); dissociates more difficult when ignited than CaCO 3 ; at 1100° the CO 2 pressure is only 20 mm. It is used for the extraction of other barium compounds, in the manufacture of bricks and terracotta, porcelain, artificial marble and barite crystal. It is prepared artificially: 1) from a crude solution of barium sulfide by introducing carbonic anhydride; 2) heating barium sulfate with potash at 5 atm pressure; 3) during the decomposition of barium sucrose by carbonic anhydride.
Barium acetate Ba (C 2 H 3 O 2) 2 ∙ H 2 O - easily soluble crystals used in dyeing; are obtained by reacting sodium sulphide or carbon dioxide with acetic acid.
Barium fluoride BaF 2 - white powder, slightly soluble in water, melts at 1280°, obtained by dissolving carbon dioxide or caustic barium in HF or boiling cryolite with aqueous barium oxide.
Barium chloride VaS l 2 ∙ 2Н 2O- colorless flat rhombic plates (specific gravity 3.05), stable in air, taste sour, poisonous; when heated, it is relatively easy to lose the first particle of water and much more difficult to lose the second; anhydrous BaCl 2 right. systems melts at 962°. 100 parts of solution contains anhydrous salt:
BaCl 2 is used for the manufacture of “strong” white and for converting vitriol contained in ceramic products into insoluble BaSO 4 ; It is extracted from barite by calcining it with coal and calcium chloride in soda furnaces at 900-1000° in a reducing flame, and a 70% solution of calcium chloride can be used, but solid calcium chloride is better:
BaSO 4 + 4C = BaS + 4CO;
BaS + CaSl 2 = VaSl 2 + CaS.
When properly produced, an almost black porous product with 50-56% BaCl 2 is obtained. After systematic leaching, the salt is crystallized (a stream of carbonic anhydride is first passed through) until hydrogen sulfide is completely removed and evaporated in vessels varnished inside. The crystals are separated by centrifugation. If anhydrous BaCl 2 is needed, then the salt is heated in vessels with stirrers to obtain very small crystals, which are then calcined, and 95% BaCl 2 is obtained. BaCl 2 can be obtained by adding BaS powder to hydrochloric acid located in closed vessels, from where it is necessary to remove the released hydrogen sulfide into a factory pipe or burn it to SO 2 using the latter for sulfuric acid. Of course, it is much more profitable to act with hydrochloric acid on BaCO 3.
Barium perchlorate Ba(C lO 3) 2 ∙ N 2O- monoclinic prisms, highly soluble in cold and even better in hot water. Explodes easily when heated and on impact if mixed with a flammable substance. Used in pyrotechnics for green flames. It is produced by electrolysis at 75° of a saturated BaCl 2 solution, with a platinum anode and a graphite cathode.
Task 2.
In a certain vessel there is a solution containing simultaneously two hydroxides: KOH and Ba(OH) 2 . To completely neutralize 30 g of this solution, 12 ml of a 20% HC1 solution was consumed (R= 1.1 g/ml). When an excess of sodium sulfate solution was added to 30 g of the same initial solution of alkalis, 2.3 g of precipitate precipitated. Determine the mass fraction of each hydroxide in the original solution.
Given:
mass of the initial alkali solution: m alkali solution = 30 g;
volume of hydrochloric acid solution: V solution HC1 = 12 ml;
mass fraction of HC1 in hydrochloric acid: (HC1) = 20%;
density of hydrochloric acid solution: R HCl solution = 1.1 g/ml;
sediment mass: m sediment = 2.3 g.
Find:
mass fraction of KOH in the initial alkali solution: (KOH) = ?
mass fraction of Ba(OH) 2 in the initial alkali solution: (Ba(OH) 2) = ?
Solution:
This task is complex and, in addition to the type of tasks under consideration, includes the topic “solutions”.
First, let's analyze the chemical transformations described in the problem.
1. The addition of hydrochloric acid to the initial alkali solution leads to the simultaneous occurrence of two neutralization reactions:
KOH + HC1 = KS1 + H 2 O (No. 1
)
Ba(OH) 2 + 2HC1 = BaC1 2 + 2H 2 O (No. 2
)
2. Sodium sulfate is a selective reagent for Ba 2+ ions in solution. When Na 2 SO 4 is added to the original alkali solution, a reaction occurs only with barium hydroxide. As a result, a precipitate of barium sulfate precipitates.
Ba(OH) 2 + Na 2 SO 4 = BaSO 4 ↓+ 2 NaOH (No. 3 )
Thus, from the mass of the precipitate, which is indicated in the condition, it is possible to determine the mass of Ba(OH) 2 in 30 g of the original solution of two hydroxides. Further, based on the data on the neutralization of hydrochloric acid and using the previously obtained information on the content of Ba(OH) 2, it is possible to find the mass of (KOH). Then we will determine the mass fraction of each hydroxide in the original solution.
The solution algorithm can be presented as follows:
1. Using reaction No. 3, we determine the mass of barium hydroxide in 30 g of the original solution.
Let's make a proportion:
x g Ba(OH)2 gives 2.3 g BaSO4 (according to the conditions)
171.3 g Ba(OH) 2 gives 233.3 g BaSO 4 (according to the equation)
(contained in 30 g of the original alkali solution).
2. According to reaction No. 2 Let us determine the mass of HC1, which was spent on neutralizing Ba(OH) 2 in the first 30-gram portion of the initial alkali solution.
Let's make a proportion:
1.69 g Ba(OH) 2 interact with x g HC1 (according to conditions)
171.3 g Ba(OH) 2 interacts with 73 g of HC1 (according to equation)
(HC1 was consumed to neutralize Ba(OH)2.
3. Using data on volume and density, we determine the mass of the hydrochloric acid solution. Next, using the mass fraction of HC1 in the solution, we find the mass of hydrogen chloride.
Barium oxide is known as a compound of barium and oxygen. In written notation as part of chemical formulas, barium oxide is designated as BaO. In a number of chemical reactions it acts as an oxide of the main type. An elementary visual analysis of the substance is also acceptable in accordance with standard conditions, where BaO is presented in the form of colorless crystals with a cubic lattice.
Barium oxide is one of the elements belonging to subgroup IV, that is, inorganic bases represented by metal oxides, hydroxides and peroxides. Any of the bases of this type is a compound where the presence of a hydroxyl radical (OH) is clearly expressed. Such bases react with acid, resulting in the formation of salts.
The raw material primarily used in the production of barium is in the form of barite or, less commonly, witherite. The reaction to produce barium oxide is a reaction of the reduction of minerals using coal, coke or natural gas. Actually, it is as a result of the interaction of these substances that the stable production of barium sulfide and oxide occurs.
Basic reaction equations for barium oxide
The reaction between metal barium and oxygen, resulting in the formation of barium oxide: 2Ba + O2 → 2BaO. This type of reaction ensures the production of not only barium oxide, but also barium peroxide: Ba + O2 → BaO2;
The decomposition reaction of barium carbonate subject to mandatory heating, where the production of barium oxide is accompanied by the release of carbon dioxide: BaCO3 → BaO + CO2. There is a reverse reaction between barium oxide and carbon(IV) monoxide under room temperature conditions;
The decomposition reaction of barium nitrate under heating conditions, where the resulting substances are barium oxide, nitrogen oxide and oxygen: 2Ba(NO3)2 → 2BaO + 4NO2 + O2;
The reaction of barium hydroxide and sulfur oxide (IV): Ba(HO)2 + 2SO2 → Ba(HSO3)2, where the result of the interaction of substances is the formation of (Ba(HSO3)2).
It is also possible to obtain barium metal by performing a reduction reaction. The main thing is which oxide to use additionally in the reaction. For example, the most striking reaction is a chemical reaction involving aluminum oxide:
3BaO + 2Al → 3Ba + Al2O3
In addition, guaranteed production of barium is ensured by electrolysis of a mixture of barium chloride and calcium in a molten state.
Solubility degree Ba
The solubility of barium oxide is determined by the reaction of this substance with water. In this case, based on the interaction equation data:
BaO + H2O = Ba(OH)2,
Where barium oxide is a basic type oxide.
Therefore, such an oxide will correspond to a base - Ba(OH)2. By checking the obtained data with the table of solubility of substances, it is easy to determine that this type of base is soluble and confirms the fact that the reaction is quite feasible.
Natural sources of the substance
- . The earth's crust, where the mass of the substance is 0.05%;
- . Sea water, where the average barium content is 0.02 mg/liter.
Application areas of basic type oxides
Any of the chemical compounds of this group is widely used in various branches of modern industry. In accordance with the brief classification of substances, the following distinction can be made between the use of oxides (potassium, magnesium, barium, aluminum):
- . Potassium oxide. Widely used in the production of mineral fertilizers used in agriculture;
- . Sodium oxide. Indispensable in the chemical industry for the production of sodium hydroxide;
- . Barium oxide. Let's use it as a catalyst in chemical reactions;
- . Magnesium oxide. Area of application: food industry (in the form of additive E530).
Determination of the chemical properties of a substance in practice
The reaction between barium oxide and water proceeds vividly, resulting in the formation of an alkali with a parallel release of heat: BaO + H2O → Ba(OH)2.
Barium oxide also interacts with acidic oxides, resulting in the formation of salts: BaO + CO2 → BaCO3, BaO + SO3 → Ba SO4↓, where barium oxide reacts with sulfur trioxide;
The reaction of BaO with acids, which ensures the final formation of salts and water: BaO + H2Cl → BaCl2 + H2O, BaO + H2SO4 → Ba SO4 ↓ + H2O. During a similar reaction between barium oxide and sulfuric acid (in dilute form), the result is the formation of barium sulfate and water.
It is also worth paying attention to the reaction of barium oxide with hydrochloric acid: BaO + 2HCl (under the obligatory condition of a dilute state) → BaCl2 + H2O, where the result of the reaction ensures the formation of barium chloride BaCl2 and water H2O.
Description of the physical properties of BaO
Exists in solid state. Barium itself is distinguished by a characteristic silvery-white hue and is quite ductile, which is why it is classified as a malleable metal.
- . The molar mass of barium oxide, g/mol: 153, 3394;
- . In terms of density, the substance is characterized by the following indicators, subject to a temperature regime of 20 °C: 5.72;
- . Solubility in water, that is, the Ks index, at a temperature of 20 ° C = 1.5 g/100 g;
Features of barium hydroxide and peroxide
Barium hydroxide is designated as Ba(OH). It is used in the form of white crystalline plates, or in a solution state, better known as barite water. Popular in the glass industry, for example for the creation and development of impenetrable glass for X-ray machines. Also used in the production of ceramic products, in water purification processes and in the production of potassium hydroxide.
Barium peroxide, referred to as BaO, is produced by heating barium oxide in an air space characterized by the absence of carbon dioxide.
Application
The yield of BaO is quite low; therefore, given its low cost, it is in high demand for coating cathodes included in electron-vacuum devices, on elements of television devices and oscilloscope tubes. Other areas of active application are also known:
- . Production of anti-corrosion materials;
- . Products from the category of ferroelectric and piezoelectrics;
- . Manufacturing of optical instruments such as prisms, lenses and others;
- . Pyrotechnic products for the purpose of coloring the flame of a charge green;
- . Nuclear-hydrogen and nuclear energy industry;
- . As part of fluorine batteries, as an electrolyte component;
- . In the development and production of medical equipment.
Storage
Conditions for proper storage of WAW imply the complete absence of any flammable substances. Also excluded from close storage and presence are reducing agents and metals in powder form. The parallel presence of any food products and farm animal feed is strictly prohibited.
Special symbols on packaging
Simultaneous transportation with food products, cosmetic products, animal feed and any aquatic organisms is completely excluded. All transported material must be marked with the following symbols:
- . Xn, indicating the irritant effect of the noted substances;
- . R, with a numerical value of 20/22, which indicates a danger if inhaled and if swallowed;
- . S, with a numerical value of 17, which prescribes the substance to be wounded at the maximum distance from fuels and lubricants;
- . S, with a numerical value of 28, indicating immediate rinsing if BaO gets on the surface of the skin.
Packaging options involve distributing the substance into packages of 1, 20 - 25, 100, 500 and 1000 kilogram packages, which are glass jars, polypropylene bags, polyethylene bags. On packaging of any weight, the hazard class must be indicated: 5.1. There is a concept of secondary hazard, signified by 6.1.
The influence of VaO on the human body
Symptoms of barium poisoning are usually expressed as follows: increased salivation, burning in the mouth, discomfort in the esophagus. The period of poisoning is accompanied by pronounced pain in the stomach, nausea, vomiting, and acute colic. In case of severe poisoning, death is likely to occur within 24 hours. The lethal dose is about 0.8 grams.
When using any barium compounds, it is worth remembering that studying it is not enough, and it is not a vital trace element. The substance is characterized as highly toxic, so in case of any type of contact it is recommended to take all precautions and PPE.