Symmetry is associated with harmony and order. And for good reason. Because the question of what symmetry is, there is an answer in the form of a literal translation from ancient Greek. And it turns out that it means proportionality and immutability. And what could be more orderly than a strict definition of location? And what can be called more harmonious than something that strictly corresponds to size?
What does symmetry mean in different sciences?
Biology. An important component of symmetry in it is that animals and plants have regularly arranged parts. Moreover, there is no strict symmetry in this science. There is always some asymmetry. It admits that the parts of the whole do not coincide with absolute precision.
Chemistry. The molecules of a substance have a certain pattern in their arrangement. It is their symmetry that explains many properties of materials in crystallography and other branches of chemistry.Physics. A system of bodies and changes in it are described using equations. They contain symmetrical components, which simplifies the entire solution. This is accomplished by searching for conserved quantities.
Mathematics. It is there that basically explains what symmetry is. Moreover, it is given greater importance in geometry. Here, symmetry is the ability to display in figures and bodies. In a narrow sense, it comes down simply to a mirror image.
How do different dictionaries define symmetry?
No matter which of them we look at, the word “proportionality” will appear everywhere. In Dahl one can also see such an interpretation as uniformity and equality. In other words, symmetrical means the same. It also says that it is boring; something that doesn’t have it looks more interesting.
When asked what symmetry is, Ozhegov’s dictionary already talks about the sameness in the position of parts relative to a point, line or plane.
Ushakov’s dictionary also mentions proportionality, as well as the complete correspondence of two parts of the whole to each other.
When do we talk about asymmetry?
The prefix “a” negates the meaning of the main noun. Therefore, asymmetry means that the arrangement of elements does not lend itself to a certain pattern. There is no immutability in it.
This term is used in situations where the two halves of an item are not completely identical. Most often they are not at all similar.
In living nature, asymmetry plays an important role. Moreover, it can be both useful and harmful. For example, the heart is placed in the left half of the chest. Due to this, the left lung is significantly smaller in size. But it is necessary.
About central and axial symmetry
In mathematics, the following types are distinguished:
- central, that is, made relative to one point;
- axial, which is observed near a straight line;
- specular, it is based on reflections;
- transfer symmetry.
What is an axis and center of symmetry? This is a point or line relative to which any point on the body can find another. Moreover, such that the distance from the original to the resulting one is divided in half by the axis or center of symmetry. As these points move, they describe identical trajectories.
The easiest way to understand what symmetry about an axis is is with an example. The notebook sheet needs to be folded in half. The fold line will be the axis of symmetry. If you draw a perpendicular line to it, then all the points on it will have points lying at the same distance on the other side of the axis.
In situations where it is necessary to find the center of symmetry, you need to proceed as follows. If there are two figures, then find their identical points and connect them with a segment. Then divide in half. When there is only one figure, knowledge of its properties can help. Often this center coincides with the intersection point of the diagonals or heights.
What shapes are symmetrical?
Geometric figures can have axial or central symmetry. But this is not a necessary condition; there are many objects that do not possess it at all. For example, a parallelogram has a central one, but it does not have an axial one. But non-isosceles trapezoids and triangles have no symmetry at all.
If central symmetry is considered, there are quite a lot of figures that have it. These are a segment and a circle, a parallelogram and all regular polygons with a number of sides that is divisible by two.
The center of symmetry of a segment (also a circle) is its center, and for a parallelogram it coincides with the intersection of the diagonals. While for regular polygons this point also coincides with the center of the figure.
If a straight line can be drawn in a figure, along which it can be folded, and the two halves coincide, then it (the straight line) will be an axis of symmetry. What's interesting is how many axes of symmetry different shapes have.
For example, an acute or obtuse angle has only one axis, which is its bisector.
If you need to find the axis in an isosceles triangle, then you need to draw the height to its base. The line will be the axis of symmetry. And just one. And in an equilateral one there will be three of them at once. In addition, the triangle also has central symmetry relative to the point of intersection of the heights.
A circle can have an infinite number of axes of symmetry. Any straight line that passes through its center can fulfill this role.
A rectangle and a rhombus have two axes of symmetry. In the first, they pass through the middles of the sides, and in the second, they coincide with the diagonals.
The square combines the previous two figures and has 4 axes of symmetry at once. They are the same as those of a rhombus and a rectangle.
So, as for geometry: there are three main types of symmetry.
Firstly, central symmetry (or symmetry about a point) - this is a transformation of the plane (or space), in which a single point (point O - the center of symmetry) remains in place, while the remaining points change their position: instead of point A, we get point A1 such that point O is the middle of the segment AA1. To construct a figure Ф1, symmetrical to the figure Ф relative to the point O, you need to draw a ray through each point of the figure Ф, passing through the point O (center of symmetry), and on this ray lay a point symmetrical to the chosen one relative to the point O. The set of points constructed in this way will give the figure F1.
Of great interest are figures that have a center of symmetry: with symmetry about the point O, any point in the figure Φ is again transformed into a certain point in the figure Φ. There are many such figures in geometry. For example: a segment (the middle of the segment is the center of symmetry), a straight line (any point of it is the center of its symmetry), a circle (the center of the circle is the center of symmetry), a rectangle (the point of intersection of its diagonals is the center of symmetry). There are many centrally symmetrical objects in living and inanimate nature (student message). Often people themselves create objects that have a center symmetries (examples from handicrafts, examples from mechanical engineering, examples from architecture and many other examples).
Secondly, axial symmetry (or symmetry about a straight line) - this is a transformation of a plane (or space), in which only the points of the straight line p remain in place (this straight line is the axis of symmetry), while the remaining points change their position: instead of point B we obtain a point B1 such that the straight line p is the perpendicular bisector to the segment BB1 . To construct a figure Ф1, symmetrical to the figure Ф, relative to the straight line р, it is necessary for each point of the figure Ф to construct a point symmetrical to it relative to the straight line р. The set of all these constructed points gives the desired figure F1. There are many geometric figures that have an axis of symmetry.
A rectangle has two, a square has four, a circle has any straight line passing through its center. If you look closely at the letters of the alphabet, you can find among them those that have horizontal or vertical, and sometimes both, axes of symmetry. Objects with axes of symmetry are quite often found in living and inanimate nature (student reports). In his activity, a person creates many objects (for example, ornaments) that have several axes of symmetry.
______________________________________________________________________________________________________
Third, plane (mirror) symmetry (or symmetry about a plane)
- this is a transformation of space in which only points of one plane retain their location (α-symmetry plane), the remaining points of space change their position: instead of point C, a point C1 is obtained such that the plane α passes through the middle of the segment CC1, perpendicular to it.
To construct a figure Ф1, symmetrical to the figure Ф relative to the plane α, it is necessary for each point of the figure Ф to build points symmetrical relative to α; they, in their set, form the figure Ф1.
Most often, in the world of things and objects around us, we encounter three-dimensional bodies. And some of these bodies have planes of symmetry, sometimes even several. And man himself, in his activities (construction, handicrafts, modeling, ...) creates objects with planes of symmetry.
It is worth noting that, along with the three listed types of symmetry, there are (in architecture)portable and rotating, which in geometry are compositions of several movements.
Two figures are called symmetrical with respect to any point O in space if each point A of one figure corresponds in the other figure to point A, located on straight line OA on the other side of point O, at a distance equal to the distance of point A from point O (Fig. 114). Point O is called center of symmetry figures.
We have already seen an example of such symmetrical figures in space (§ 53), when, by continuing the edges and faces of a polyhedral angle beyond the vertex, we obtained a polyhedral angle symmetrical to the given one. The corresponding segments and angles that make up two symmetrical figures are equal to each other. Nevertheless, the figures as a whole cannot be called equal: they cannot be combined with one another due to the fact that the order of the parts in one figure is different than in the other, as we saw in the example of symmetrical polyhedral angles.
In some cases, symmetrical figures can be combined, but their incongruous parts will coincide. For example, let’s take a right trihedral angle (Fig. 115) with a vertex at point O and edges OX, OY, OZ.
Let us construct a symmetrical angle OXYZ for it. Angle OXYZ can be combined with OXYZ so that edge OX coincides with OY, and edge OY coincides with OX. If we combine the corresponding edges OX with OX and OY with OY, then the edges OZ and OZ will be directed in opposite directions.
If symmetrical figures together constitute one geometric body, then this geometric body is said to have a center of symmetry. Thus, if a given body has a center of symmetry, then every point belonging to this body corresponds to a symmetrical point, also belonging to this body. Of the geometric bodies we have considered, for example, they have a center of symmetry:
- parallelepiped,
- a prism that has a regular polygon at its base with an even number of sides.
A regular tetrahedron has no center of symmetry.
Symmetry relative to the plane
Two spatial figures are called symmetrical with respect to the plane P if each point A in one figure corresponds to a point A in the other, and the segment AA is perpendicular to the plane P and is divided in half at the point of intersection with this plane.
Theorem. Any two corresponding segments in two symmetrical figures are equal to each other.
Let two figures be given, symmetrical with respect to the plane P. Let us select some two points A and B of the first figure, let A and B be the corresponding points of the second figure (Figure 116, the figures are not shown in the drawing).
Let further C be the point of intersection of the segment AA with the plane P, D be the point of intersection of the segment BB with the same plane. By connecting points C and D with a straight line segment, we obtain two quadrilaterals ABDC and ABDC. Since AC = AC, BD = BD and
∠ACD = ∠ACD, ∠BDC = ∠BDC, as right angles, then these quadrilaterals are equal (which we can easily verify by superposition). Therefore, AB = AB. It directly follows from this theorem that the corresponding plane and dihedral angles of two figures that are symmetrical about the plane are equal to each other. Nevertheless, it is impossible to combine these two figures with one another so that their corresponding parts are combined, since the order of the parts in one figure is the opposite of that which takes place in the other. The simplest example of two figures that are symmetrical relative to a plane are: any object and its reflection in a plane mirror; Every figure is symmetrical with its mirror image relative to the plane of the mirror.
If any geometric body can be divided into two parts that are symmetrical with respect to a certain plane, then this plane is called the plane of symmetry of this body.
Geometric bodies with a plane of symmetry are extremely common in nature and in everyday life. The body of humans and animals has a plane of symmetry, dividing it into right and left parts.
This example makes it especially clear that symmetrical figures cannot be combined. Thus, the hands of the right and left hands are symmetrical, but they cannot be combined, which can be seen at least from the fact that the same glove cannot fit both the right and left hands. A large number of household items have a plane of symmetry: a chair, a dining table, a bookcase, a sofa, etc. Some, such as a dining table, even have not one, but two planes of symmetry (Fig. 117).
Usually, when considering an object that has a plane of symmetry, we strive to take such a position in relation to it that the plane of symmetry of our body, or at least our head, coincides with the plane of symmetry of the object itself. In this case, the symmetrical shape of the object becomes especially noticeable.
Symmetry about the axis. Axis of symmetry of the second order.
Two figures are called symmetrical with respect to the l axis (the axis is a straight line) if each point A of the first figure corresponds to a point A of the second figure, so that the segment AA is perpendicular to the l axis, intersects with it and is divided in half at the intersection point. The l axis itself is called the second order axis of symmetry.From this definition it immediately follows that if two geometric bodies, symmetrical about any axis, are intersected by a plane perpendicular to this axis, then in the section we get two flat figures, symmetrical about the point of intersection of the plane with the axis of symmetry of the bodies.
From here it is further easy to deduce that two bodies that are symmetrical about an axis can be combined with one another by rotating one of them 180° around the axis of symmetry. In fact, let us imagine all possible planes perpendicular to the axis of symmetry.
Each such plane intersecting both bodies contains figures that are symmetrical with respect to the point where the plane meets the axis of symmetry of the bodies. If you force the cutting plane to slide on its own, rotating it around the axis of symmetry of the body by 180°, then the first figure coincides with the second.
This is true for any cutting plane. Rotation of all sections of the body by 180° is equivalent to rotation of the entire body by 180° around the axis of symmetry. This is where the validity of our statement follows.
If, after rotating a spatial figure around a certain straight line by 180°, it coincides with itself, then the figure is said to have this straight line as its second-order symmetry axis.
The name “second-order symmetry axis” is explained by the fact that during a full revolution around this axis, the body will, in the process of rotation, twice take a position coinciding with the original one (including the original one). Examples of geometric bodies that have an axis of symmetry of the second order are:
1) a regular pyramid with an even number of side faces; its axis of symmetry is its height;
2) rectangular parallelepiped; it has three axes of symmetry: straight lines connecting the centers of its opposite faces;
3) regular prism with an even number of side faces. The axis of its symmetry is each straight line connecting the centers of any pair of its opposite faces (the side faces and the two bases of the prism). If the number of lateral faces of the prism is 2 k, then the number of such axes of symmetry will be k+ 1. In addition, the axis of symmetry for such a prism is each straight line connecting the midpoints of its opposite side edges. The prism has such axes of symmetry A.
So the correct one is 2 k-faceted prism has 2 k+1 axes, symmetry.
Dependence between different types of symmetry in space.
There is a relationship between different types of symmetry in space - axial, planar and central - expressed by the following theorem.Theorem. If the figure F is symmetrical with the figure F relative to the plane P and at the same time symmetrical with the figure F" relative to the point O lying in the plane P, then the figures F and F" are symmetrical relative to the axis passing through the point O and perpendicular to the plane P .
Let's take some point A of figure F (Fig. 118). It corresponds to point A of figure F and point A" of figure F" (the figures themselves F, F and F" are not shown in the drawing).
Let B be the point of intersection of the segment AA with the plane P. Let us draw a plane through points A, A and O. This plane will be perpendicular to the plane P, since it passes through the line AA perpendicular to this plane. In the plane AAO we draw a straight line OH perpendicular to OB. This straight line OH will also be perpendicular to the plane P. Next, let C be the intersection point of the lines AA" and OH.
In the triangle AAA" the segment BO connects the midpoints of the sides AA and AA", therefore, BO || AA", but VO⊥OH, which means AA"⊥OH. Further, since O is the midpoint of side AA", and CO || AA, then AC = A"C. From here we conclude that the points A and A" are symmetrical relative to the axis OH. The same is true for all other points of the figure. This means that our theorem is proven. From this theorem it immediately follows that two figures that are symmetrical relative to the plane cannot be combined so that their corresponding parts are combined. In fact, the figure F is combined with F" by rotating around the OH axis by 180°. But the figures F" and F cannot be combined as symmetrical with respect to the point, therefore, the figures F and F also cannot be combined.
Higher order axes of symmetry
A figure that has an axis of symmetry aligns with itself after rotating around the axis of symmetry through an angle of 180°. But cases are possible when the figure comes into alignment with its original position after rotating around a certain axis by an angle less than 180°. Thus, if a body makes a full revolution around this axis, then during the rotation process it will align with its original position several times. Such an axis of rotation is called an axis of symmetry of higher order, and the number of positions of the body that coincide with the initial one is called the order of the axis of symmetry. This axis may not coincide with the axis of symmetry of the second order. Thus, a regular triangular pyramid does not have a second-order symmetry axis, but its height serves as a third-order symmetry axis for it. In fact, after rotating this pyramid around the height at an angle of 120°, it aligns with itself (Fig. 119).
When the pyramid rotates around a height, it can occupy three positions that coincide with the original one, including the original one. It is easy to notice that every symmetry axis of even order is at the same time an symmetry axis of second order.
Examples of higher order symmetry axes:
1) Correct n-a carbon pyramid has an axis of symmetry n-th order. This axis is the height of the pyramid.
2) Correct n- a carbon prism has an axis of symmetry n-th order. This axis is a straight line connecting the centers of the bases of the prism.
Symmetry of the cube.
As for any parallelepiped, the point of intersection of the diagonals of the cube is the center of its symmetry.The cube has nine planes of symmetry: six diagonal planes and three planes passing through the midpoints of each four of its parallel edges.
The cube has nine axes of symmetry of the second order: six straight lines connecting the midpoints of its opposite edges, and three straight lines connecting the centers of opposite faces (Fig. 120).
These last straight lines are axes of symmetry of the fourth order. In addition, the cube has four third-order axes of symmetry, which are its diagonals. In fact, the diagonal of the cube AG (Fig. 120) is obviously equally inclined to the edges AB, AD and AE, and these edges are equally inclined to one another. If we connect points B, D and E, we get a regular triangular pyramid ADBE, for which the diagonal of the cube AG serves as the height. When this pyramid aligns with itself when rotated around the height, the entire cube will align with its original position. As is easy to see, the cube has no other axes of symmetry. Let's see how many different ways a cube can be combined with itself. Rotation around the ordinary axis of symmetry gives one position of the cube, different from the original one, in which the cube as a whole is aligned with itself.
Rotation around a third-order axis produces two such positions, and rotation around a fourth-order axis produces three such positions. Since the cube has six axes of the second order (these are ordinary axes of symmetry), four axes of the third order and three axes of the fourth order, there are 6 1 + 4 2 + 3 3 = 23 positions of the cube, different from the original one, at which it is combined with itself yourself.
It is easy to verify directly that all these positions are different from one another, and also from the initial position of the cube. Together with the starting position, they make up 24 ways of combining the cube with itself.
Other materialsSince sulfur occurs in nature in a native state, it was known to man already in ancient times. Alchemists paid great attention to sulfur. Many of them already knew sulfuric acid. Vasily Valentin in the 15th century. described in detail its preparation (by heating iron sulfate). Sulfuric acid was produced industrially for the first time in England in the mid-18th century.
Being in nature, receiving:
Significant deposits of sulfur are often found in nature (mostly near volcanoes). The most common sulfides are: iron pyrite (pyrite) FeS 2, copper pyrite CuFeS 2, lead luster PbS and zinc blende ZnS. Sulfur is even more commonly found in the form of sulfates, such as calcium sulfate (gypsum and anhydrite), magnesium sulfate (bitter salt and kieserite), barium sulfate (heavy spar), strontium sulfate (celestine), sodium sulfate (Glauber's salt).
Receipt. 1. Smelting native sulfur from natural deposits, for example, using steam, and purifying raw sulfur by distillation.
2. Sulfur release during desulfurization of coal gasification products (water, air and lighting gases), for example, under the influence of air and activated carbon catalyst: 2H 2 S + O 2 = 2H 2 O + 2S
3. Release of sulfur during incomplete combustion of hydrogen sulfide (see equation above), upon acidification of sodium thiosulfate solution: Na 2 S 2 O 3 + 2HCI = 2NaCI + SO 2 + H 2 O + S
and when distilling a solution of ammonium polysulfide: (NH 4) 2 S 5 = (NH 4) 2 S + 4S
Physical properties:
Sulfur is a hard, brittle, yellow substance. It is practically insoluble in water, but dissolves well in carbon disulfide, aniline and some other solvents. Conducts heat and electricity poorly. Sulfur forms several allotropic modifications. ???...
...
At 444.6°C, sulfur boils, forming dark brown vapors.
Chemical properties:
The sulfur atom, having an incomplete external energy level, can attach two electrons and exhibit an oxidation state of -2. When electrons are given up or withdrawn to an atom of a more electronegative element, the oxidation state of sulfur can be +2, +4 and +6.
When sulfur burns in air or in oxygen, sulfur oxide (IV) SO 2 and partially sulfur oxide (VI) SO 3 are formed. When heated, it combines directly with hydrogen, halogens (except iodine), phosphorus, coal, and all metals except gold, platinum and iridium. For example:
S + H 2 = H 2 S; 3S + 2P = P 2 S 3 ; S + CI 2 = SCI 2 ; 2S + C = CS 2 ; S + Fe = FeS
As follows from the examples, in reactions with metals and some non-metals, sulfur is an oxidizing agent, and in reactions with more active non-metals, such as oxygen, chlorine, it is a reducing agent.
In relation to acids and alkalis...
...
The most important connections:
Sulfur dioxide, SO 2 is a colorless, heavy gas with a pungent odor, very easily soluble in water. In solution, SO 2 is easily oxidized.
Sulfurous acid, H 2 SO 3: dibasic acid, its salts are called sulfites. Sulfurous acid and its salts are strong reducing agents.
Sulfur trioxide, SO 3: colorless liquid, very strongly absorbs moisture forming sulfuric acid. Has the properties of acid oxides.
Sulfuric acid, H 2 SO 4: a very strong dibasic acid, even with moderate dilution, almost completely dissociates into ions. Sulfuric acid is low-volatile and displaces many other acids from their salts. The resulting salts are called sulfates, crystal hydrates are called vitriol. (for example, copper sulfate CuSO 4 * 5H 2 O, forms blue crystals).
Hydrogen sulfide, H 2 S: colorless gas with the smell of rotten eggs, boiling point = - 61°C. One of the weakest acids. Salts - sulfides
...
...
...
Application:
Sulfur is widely used in industry and agriculture. About half of its production is used to produce sulfuric acid. Sulfur is used to vulcanize rubber. In the form of sulfur color (fine powder), sulfur is used to combat diseases of vineyards and cotton. It is used to produce gunpowder, matches, and luminous compounds. In medicine, sulfur ointments are prepared to treat skin diseases.
Myakisheva E.A.
HF Tyumen State University, 561 gr.
Sources:
1. Chemistry: Reference. Ed./V. Schröter. – M.: Chemistry, 1989.
2. G. Remy “Course of inorganic chemistry” - M.: Chemistry, 1972.
In this article you will find information about what sulfur oxide is. Its basic chemical and physical properties, existing forms, methods of their preparation and differences from each other will be considered. The applications and biological role of this oxide in its various forms will also be mentioned.
What is the substance
Sulfur oxide is a compound of simple substances, sulfur and oxygen. There are three forms of sulfur oxides, differing in the degree of valence S, namely: SO (sulfur monoxide, sulfur monoxide), SO 2 (sulfur dioxide or sulfur dioxide) and SO 3 (sulfur trioxide or anhydride). All of the listed variations of sulfur oxides have similar chemical and physical characteristics.
General information about sulfur monoxide
Divalent sulfur monoxide, or otherwise sulfur monoxide, is an inorganic substance consisting of two simple elements - sulfur and oxygen. Formula - SO. Under normal conditions, it is a colorless gas, but with a pungent and specific odor. Reacts with an aqueous solution. Quite a rare compound in the earth's atmosphere. It is unstable to temperature and exists in dimeric form - S 2 O 2 . Sometimes it is capable of interacting with oxygen to form sulfur dioxide as a result of the reaction. Does not form salts.
Sulfur oxide (2) is usually obtained by burning sulfur or decomposing its anhydride:
- 2S2+O2 = 2SO;
- 2SO2 = 2SO+O2.
The substance dissolves in water. As a result, sulfur oxide forms thiosulfuric acid:
- S 2 O 2 + H 2 O = H 2 S 2 O 3 .
General data on sulfur dioxide
Sulfur oxide is another form of sulfur oxides with the chemical formula SO 2. It has an unpleasant specific odor and is colorless. When subjected to pressure, it can ignite at room temperature. When dissolved in water, it forms unstable sulfurous acid. Can dissolve in ethanol and sulfuric acid solutions. It is a component of volcanic gas.
In industry it is obtained by burning sulfur or roasting its sulfides:
- 2FeS 2 +5O 2 = 2FeO+4SO 2.
In laboratories, as a rule, SO 2 is obtained using sulfites and hydrosulfites, exposing them to strong acid, as well as to exposure of metals with a low degree of activity to concentrated H 2 SO 4.
Like other sulfur oxides, SO2 is an acidic oxide. Interacting with alkalis, forming various sulfites, it reacts with water, creating sulfuric acid.
SO 2 is extremely active, and this is clearly expressed in its reducing properties, where the oxidation state of sulfur oxide increases. May exhibit oxidizing properties if exposed to a strong reducing agent. The latter characteristic is used for the production of hypophosphorous acid, or for the separation of S from gases in the metallurgical field.
Sulfur oxide (4) is widely used by humans to produce sulfurous acid or its salts - this is its main area of application. It also participates in winemaking processes and acts there as a preservative (E220); sometimes it is used to pickle vegetable stores and warehouses, as it destroys microorganisms. Materials that cannot be bleached with chlorine are treated with sulfur oxide.
SO 2 is a rather toxic compound. Characteristic symptoms indicating poisoning are coughing, breathing problems, usually in the form of a runny nose, hoarseness, an unusual taste and a sore throat. Inhalation of such gas can cause suffocation, impaired speech ability of the individual, vomiting, difficulty swallowing, and acute pulmonary edema. The maximum permissible concentration of this substance in the work area is 10 mg/m3. However, different people's bodies may exhibit different sensitivity to sulfur dioxide.
General information about sulfuric anhydride
Sulfur gas, or sulfuric anhydride as it is called, is a higher oxide of sulfur with the chemical formula SO 3. Liquid with a suffocating odor, highly volatile under standard conditions. It is capable of solidifying, forming crystalline mixtures from its solid modifications, at temperatures of 16.9 °C and below.
Detailed analysis of higher oxide
When SO 2 is oxidized with air under the influence of high temperatures, a necessary condition is the presence of a catalyst, for example V 2 O 5, Fe 2 O 3, NaVO 3 or Pt.
Thermal decomposition of sulfates or interaction of ozone and SO 2:
- Fe 2 (SO 4)3 = Fe 2 O 3 +3SO 3;
- SO 2 +O 3 = SO 3 +O 2.
Oxidation of SO 2 with NO 2:
- SO 2 +NO 2 = SO 3 +NO.
Physical qualitative characteristics include: the presence in the gas state of a flat structure, trigonal type and D 3 h symmetry; during the transition from gas to crystal or liquid, it forms a trimer of a cyclic nature and a zigzag chain, and has a covalent polar bond.
In solid form, SO 3 occurs in alpha, beta, gamma and sigma forms, and it has, accordingly, different melting points, degrees of polymerization and a variety of crystalline forms. The existence of such a number of SO 3 species is due to the formation of donor-acceptor type bonds.
The properties of sulfur anhydride include many of its qualities, the main ones being:
Ability to interact with bases and oxides:
- 2KHO+SO 3 = K 2 SO 4 +H 2 O;
- CaO+SO 3 = CaSO 4.
Higher sulfur oxide SO3 has quite a high activity and creates sulfuric acid by interacting with water:
- SO 3 + H 2 O = H2SO 4.
It reacts with hydrogen chloride and forms chlorosulfate acid:
- SO 3 +HCl = HSO 3 Cl.
Sulfur oxide is characterized by the manifestation of strong oxidizing properties.
Sulfuric anhydride is used in the creation of sulfuric acid. A small amount of it is released into the environment during the use of sulfur bombs. SO 3, forming sulfuric acid after interaction with a wet surface, destroys a variety of dangerous organisms, such as fungi.
Summing up
Sulfur oxide can be in different states of aggregation, ranging from liquid to solid form. It is rare in nature, but there are quite a few ways to obtain it in industry, as well as areas where it can be used. The oxide itself has three forms in which it exhibits different degrees of valency. May be highly toxic and cause serious health problems.