Small ice crystal. Secrets of ice crystals. The emergence and development of addiction

Sheila, the War Golem from the downloadable add-on " stone prisoner”, is significantly different from all satellites in power and skills. She uses her stone body and small crystals with various effects as weapons, and large crystals serve as her armor. You can find them during the passage of the game, they are found like regular weapons, or on sale from merchants. Crystals are divided according to the type of effects applied and reflected: spiritual, natural, electrical, ice and fire. The best are the flawless and exceptional crystals of each type. Not only do they change base stats, but they can also affect attack, defense, constitution, strength... Many crystals can be found in the Kadash Thai, where Sheila will offer to go to find out where she comes from and who she used to be, as well as on sale Garin in the Commons of Orzammar.

Small crystals for Sheila in Dragon Age: Origins:

• Small Flawless Fire Crystal- strength: 32; damage: 7.00; +3% Critical Chance melee strike, +4 damage from any weapon, +22.5% fire damage.
• Small Flawless Ice Crystal- strength: 32; damage: 7.00; +2 Armor Penetration, +10% Critical Chance. hit or backstab, +22.5% cold damage.
• Small Impeccable Electric Crystal- strength: 32; damage: 7.00; +4 Agility, +6 Attack, +22.5% Electric Damage.
• Small Flawless Natural Crystal- strength: 32; damage: 7.00; +4 to constitution and to recovery of health in battle, +22.5% to damage from the forces of nature.
• Small Chipped Spiritual Crystal- strength: 20; damage: 5.50; +5% spiritual damage.
• Small Cracked Spiritual Crystal- strength: 20; damage: 5.50; +10% spiritual damage.

Large crystals for Sheila in Dragon Age: Origins:

• Large Cracked Fire Crystal- physique: 20; armor: 10.80; +20 Fire Resistance.
• Large Cracked Ice Crystal- physique: 20; armor: 10.80; +20 Cold Resistance.
• Large Cracked Electrical Crystal- physique: 20; armor: 10.80; +20 Electricity Resistance.
• Large cracked natural crystal- physique: 20; armor: 10.80; +20 Nature Resistance.
• Large Flawless Natural Crystal- physique: 32; armor: 16.20; +1 Constitution, +3 Armor, +40 Nature Resistance, +15 Physical Resistance.
• Large Cracked Spiritual Crystal- physique: 20; armor: 10.80; +20 Spirit Resistance.
• Large Pure Spiritual Crystal- physique: 26; armor: 14.40; +30 spirit resistance, +8% chance to reflect hostile magic, +5 psychic resistance.
• Large Flawless Spiritual Crystal- physique: 32; armor: 16.20; +1 to all stats, +40 spirit resistance, +12% chance to reflect hostile magic, +15 psychic resistance.

O. V. Mosin, I. Ignatov (Bulgaria)

annotation The importance of ice in sustaining life on our planet cannot be underestimated. Ice has a great influence on the living conditions and life of plants and animals and on different types human economic activity. Covering the water, ice, due to its low density, plays the role of a floating screen in nature, protecting rivers and reservoirs from further freezing and preserving the life of underwater inhabitants. The use of ice for various purposes (snow retention, arrangement of ice crossings and isothermal warehouses, ice laying of storage facilities and mines) is the subject of a number of sections of hydrometeorological and engineering sciences, such as ice technology, snow technology, engineering permafrost, as well as the activities of special services for ice reconnaissance, icebreaking transport and snowplows. Natural ice is used for storage and cooling of foodstuffs, biological and medical products, for which it is specially produced and harvested, and melt water prepared by melting ice is used in folk medicine to increase metabolism and remove toxins from the body. The article introduces the reader to new little-known properties and modifications of ice.

Ice is a crystalline form of water, which, according to the latest data, has fourteen structural modifications. Among them there are both crystalline (natural ice) and amorphous (cubic ice) and metastable modifications that differ from each other in the mutual arrangement and physical properties of water molecules linked by hydrogen bonds that form the crystal lattice of ice. All of them, except for the usual natural ice I h , crystallizing in a hexagonal lattice, are formed under exotic conditions - at very low temperatures of dry ice and liquid nitrogen and high pressures of thousands of atmospheres, when the angles of hydrogen bonds in a water molecule change and crystal systems other than hexagonal are formed. Such conditions are reminiscent of cosmic conditions and are not found on Earth.

In nature, ice is represented mainly by one crystalline variety, crystallizing in a hexagonal lattice resembling the structure of a diamond, where each water molecule is surrounded by four molecules closest to it, located at equal distances from it, equal to 2.76 angstroms and located at the vertices of a regular tetrahedron. Due to the low coordination number, the structure of ice is a network, which affects its low density, which is 0.931 g/cm 3 .

The most unusual property of ice is the amazing variety of external manifestations. With the same crystal structure, it can look completely different, taking the form of transparent hailstones and icicles, fluffy snow flakes, a dense shiny crust of ice, or giant glacial masses. Ice occurs in nature in the form of continental, floating and underground ice, as well as in the form of snow and hoarfrost. It is widespread in all areas of human habitation. Collecting in large quantities, snow and ice form special structures with fundamentally different properties than individual crystals or snowflakes. Natural ice is formed mainly by ice of sedimentary-metamorphic origin, formed from solid atmospheric precipitation as a result of subsequent compaction and recrystallization. A characteristic feature of natural ice is granularity and banding. Granularity is due to recrystallization processes; each grain of glacial ice is an irregularly shaped crystal that closely adjoins other crystals in the ice mass in such a way that the protrusions of one crystal fit tightly into the recesses of another. Such ice is called polycrystalline. In it, each ice crystal is a layer of the thinnest leaves overlapping each other in the basal plane, perpendicular to the direction of the optical axis of the crystal.

The total reserves of ice on Earth are estimated to be about 30 million tons. km 3(Table 1). Most of the ice is concentrated in Antarctica, where the thickness of its layer reaches 4 km. There is also evidence of the presence of ice on the planets of the solar system and in comets. Ice is so important for the climate of our planet and the habitation of living beings on it that scientists have designated a special environment for ice - the cryosphere, the boundaries of which extend high into the atmosphere and deep into the earth's crust.

Tab. one. Quantity, distribution and lifetime of ice.

• Type of ice; Weight; Distribution area; Average concentration, g/cm2; Weight gain rate, g/year; Average life time, year
• G; %; million km2; %
• Glaciers; 2.4 1022; 98.95; 16.1; 10.9 sushi; 1.48 105; 2.5 1018; 9580
• underground ice; 2 1020; 0.83; 21; 14.1 sushi; 9.52 103; 6 1018; 30-75
• sea ​​ice; 3.5 1019; 0.14; 26; 7.2 oceans; 1.34 102; 3.3 1019; 1.05
• Snow cover; 1.0 1019; 0.04; 72.4; 14.2 Earths; 14.5; 2 1019; 0.3-0.5
• icebergs; 7.6 1018; 0.03; 63.5; 18.7 ocean; 14.3; 1.9 1018; 4.07
• atmospheric ice; 1.7 1018; 0.01; 510.1; 100 Earth; 3.3 10-1; 3.9 1020; 4 10-3

Ice crystals are unique in their shape and proportions. Any growing natural crystal, including an ice crystal of ice, always strives to create an ideal, regular crystal lattice, since this is beneficial from the point of view of a minimum of its internal energy. Any impurities, as is known, distort the shape of a crystal, therefore, during the crystallization of water, water molecules are first of all built into the lattice, and foreign atoms and molecules of impurities are displaced into the liquid. And only when the impurities have nowhere to go, the ice crystal begins to build them into its structure or leaves them in the form of hollow capsules with a concentrated non-freezing liquid - brine. Therefore, sea ice is fresh and even the dirtiest water bodies are covered with transparent and pure ice. When ice melts, it displaces impurities into the brine. On a planetary scale, the phenomenon of freezing and thawing of water, along with the evaporation and condensation of water, plays the role of a gigantic cleansing process in which water on Earth is constantly purifying itself.

Tab. 2. Some physical properties of ice I.

Property

Meaning

Note

Heat capacity, cal/(g °C) Heat of melting, cal/g Heat of vaporization, cal/g

0.51 (0°C) 79.69 677

Decreases strongly with decreasing temperature

Thermal expansion coefficient, 1/°C

9.1 10-5 (0°C)

Polycrystalline ice

Thermal conductivity, cal/(cm sec °C)

4.99 10 -3

Polycrystalline ice

Refractive index:

1.309 (-3°C)

Polycrystalline ice

Specific electrical conductivity, ohm-1 cm-1

10-9 (0°C)

Apparent activation energy 11 kcal/mol

Surface electrical conductivity, ohm-1

10-10 (-11°C)

Apparent activation energy 32 kcal/mol

Young's modulus of elasticity, dyne/cm2

9 1010 (-5 °C)

Polycrystalline ice

Resistance, MN/m2: crushing tear shear

2,5 1,11 0,57

polycrystalline ice polycrystalline ice polycrystalline ice

Dynamic viscosity, poise

Polycrystalline ice

Activation energy during deformation and mechanical relaxation, kcal/mol

Increases linearly by 0.0361 kcal/(mol °C) from 0 to 273.16 K

Note: 1 cal/(g °C)=4.186 kJ/(kg K); 1 ohm -1 cm -1 \u003d 100 sim / m; 1 dyn = 10 -5 N ; 1 N = 1 kg m/s²; 1 dyne/cm=10 -7 N/m; 1 cal / (cm sec ° C) \u003d 418.68 W / (m K); 1 poise \u003d g / cm s \u003d 10 -1 N sec / m 2.

Due to the wide distribution of ice on Earth, the difference in the physical properties of ice (Table 2) from the properties of other substances plays an important role in many natural processes. Ice has many other life-supporting properties and anomalies - anomalies in density, pressure, volume, and thermal conductivity. If there were no hydrogen bonds linking water molecules into a crystal, ice would melt at -90 °C. But this does not happen due to the presence of hydrogen bonds between water molecules. Due to its lower density than that of water, ice forms a floating cover on the surface of the water, which protects rivers and reservoirs from bottom freezing, since its thermal conductivity is much less than that of water. At the same time, the lowest density and volume are observed at +3.98 °C (Fig. 1). Further cooling of water to 0 0 C gradually leads not to a decrease, but to an increase in its volume by almost 10%, when the water turns into ice. This behavior of water indicates the simultaneous existence of two equilibrium phases in water - liquid and quasi-crystalline, by analogy with quasi-crystals, the crystal lattice of which not only has a periodic structure, but also has symmetry axes of different orders, the existence of which previously contradicted the ideas of crystallographers. This theory, first put forward by the well-known domestic theoretical physicist Ya. I. Frenkel, is based on the assumption that some of the liquid molecules form a quasi-crystalline structure, while the rest of the molecules are gas-like, freely moving through the volume. The distribution of molecules in a small neighborhood of any fixed water molecule has a certain order, somewhat reminiscent of crystalline, although more loose. For this reason, the structure of water is sometimes called quasi-crystalline or crystal-like, i.e., having symmetry and the presence of order in the mutual arrangement of atoms or molecules.

Rice. one. The dependence of the specific volume of ice and water on temperature

Another property is that the flow rate of ice is directly proportional to the activation energy and inversely proportional to the absolute temperature, so that as the temperature decreases, ice approaches in its properties an absolutely solid body. On average, at a temperature close to melting, the fluidity of ice is 10 6 times higher than that of rocks. Due to its fluidity, ice does not accumulate in one place, but constantly moves in the form of glaciers. The relationship between flow velocity and stress in polycrystalline ice is hyperbolic; with an approximate description of it by a power equation, the exponent increases as the voltage increases.

Visible light is practically not absorbed by ice, since light rays pass through the ice crystal, but it blocks ultraviolet radiation and most of the infrared radiation from the Sun. In these regions of the spectrum, the ice appears absolutely black, since the absorption coefficient of light in these regions of the spectrum is very high. Unlike ice crystals, white light falling on snow is not absorbed, but is refracted many times in ice crystals and reflected from their faces. That's why snow looks white.

Due to the very high reflectivity of ice (0.45) and snow (up to 0.95), the area covered by them is on average about 72 million hectares per year. km 2 in the high and middle latitudes of both hemispheres, it receives solar heat 65% less than the norm and is a powerful source of cooling of the earth's surface, which largely determines the modern latitudinal climatic zonality. In summer, in the polar regions, solar radiation is greater than in the equatorial belt, nevertheless, the temperature remains low, since a significant part of the absorbed heat is spent on melting ice, which has a very high melting heat.

Other unusual properties of ice include the generation of electromagnetic radiation by its growing crystals. It is known that most of the impurities dissolved in water are not transferred to the ice when it begins to grow; they freeze. Therefore, even on the dirtiest puddle, the ice film is clean and transparent. In this case, impurities accumulate at the boundary of solid and liquid media, in the form of two layers of electric charges of different signs, which cause a significant potential difference. The charged impurity layer moves along with the lower boundary young ice and emits electromagnetic waves. Thanks to this, the crystallization process can be observed in detail. Thus, a crystal growing in length in the form of a needle radiates differently than one covered with lateral processes, and the radiation of growing grains differs from that which occurs when crystals crack. From the shape, sequence, frequency, and amplitude of the radiation pulses, one can determine how fast the ice freezes and what kind of ice structure is formed.

But the most surprising thing about the structure of ice is that water molecules at low temperatures and high pressures inside carbon nanotubes can crystallize into a double helix shape, reminiscent of DNA molecules. This has been proven by recent computer experiments by American scientists led by Xiao Cheng Zeng from the University of Nebraska (USA). In order for water to form a spiral in a simulated experiment, it was placed in nanotubes with a diameter of 1.35 to 1.90 nm under high pressure, varying from 10 to 40,000 atmospheres, and a temperature of –23 °C was set. It was expected to see that the water in all cases forms a thin tubular structure. However, the model showed that at a nanotube diameter of 1.35 nm and an external pressure of 40,000 atmospheres, hydrogen bonds in the ice structure were bent, which led to the formation of a double-walled helix - internal and external. Under these conditions, the inner wall turned out to be twisted into a quadruple helix, and the outer wall consisted of four double helixes similar to a DNA molecule (Fig. 2). This fact can serve as confirmation of the connection between the structure of the vitally important DNA molecule and the structure of water itself and that water served as a matrix for the synthesis of DNA molecules.

Rice. 2. Computer model of the structure of frozen water in nanotubes, resembling a DNA molecule (Photo from New Scientist, 2006)

Another of the most important properties of water discovered and investigated in recent times, lies in the fact that water has the ability to remember information about past impacts. This was first proved by the Japanese researcher Masaru Emoto and our compatriot Stanislav Zenin, who was one of the first to propose a cluster theory of the structure of water, consisting of cyclic associates of a bulk polyhedral structure - clusters of the general formula (H 2 O) n, where n, according to recent data, can reach hundreds and even thousand units. It is due to the presence of clusters in water that water has informational properties. The researchers photographed the processes of water freezing into ice microcrystals, acting on it with various electromagnetic and acoustic fields, melodies, prayer, words or thoughts. It turned out that under the influence of positive information in the form of beautiful melodies and words, the ice froze into symmetrical hexagonal crystals. Where non-rhythmic music sounded, angry and insulting words, water, on the contrary, froze into chaotic and shapeless crystals. This is proof that water has a special structure that is sensitive to external information influences. Presumably, the human brain, which consists of 85-90% of water, has a strong structuring effect on water.

Emoto crystals arouse both interest and insufficiently substantiated criticism. If you look at them carefully, you can see that their structure consists of six tops. But even more careful analysis shows that snowflakes in winter have the same structure, always symmetrical and with six tops. To what extent do crystallized structures contain information about the environment where they were created? The structure of snowflakes can be beautiful or shapeless. This indicates that the control sample (cloud in the atmosphere) where they occur has the same effect on them as the initial conditions. The initial conditions are solar activity, temperature, geophysical fields, humidity, etc. All this means that from the so-called. average ensemble, we can conclude that the structure of water drops, and then snowflakes, is approximately the same. Their mass is almost the same, and they move through the atmosphere at a similar speed. In the atmosphere, they continue to shape their structures and increase in volume. Even if they formed in different parts of the cloud, there are always a certain number of snowflakes in the same group that arose under almost the same conditions. And the answer to the question of what constitutes positive and negative information about snowflakes can be found in Emoto. Under laboratory conditions, negative information (an earthquake, sound vibrations unfavorable for a person, etc.) does not form crystals, but positive information, just the opposite. It is very interesting to what extent one factor can form the same or similar structures of snowflakes. The highest density of water is observed at a temperature of 4 °C. It has been scientifically proven that the density of water decreases when hexagonal ice crystals begin to form as the temperature drops below zero. This is the result of the action of hydrogen bonds between water molecules.

What is the reason for this structuring? Crystals are solids, and their constituent atoms, molecules or ions are arranged in a regular, repeating structure, in three spatial dimensions. The structure of water crystals is slightly different. According to Isaac, only 10% of the hydrogen bonds in ice are covalent, i.e. with fairly stable information. Hydrogen bonds between the oxygen of one water molecule and the hydrogen of another are most sensitive to external influences. The spectrum of water during the formation of crystals is relatively different in time. According to the effect of discrete evaporation of a water drop proved by Antonov and Yuskeseliyev and its dependence on the energy states of hydrogen bonds, we can look for an answer about the structuring of crystals. Each part of the spectrum depends on the surface tension of the water droplets. There are six peaks in the spectrum, which indicate the ramifications of the snowflake.

Obviously, in Emoto's experiments, the initial "control" sample has an effect on the appearance of the crystals. This means that after exposure to a certain factor, the formation of such crystals can be expected. It is almost impossible to get identical crystals. When testing the effect of the word "love" on water, Emoto does not clearly indicate whether this experiment was carried out with different samples.

Doubly blind experiments are needed to test whether the Emoto technique differentiates sufficiently. Isaac's proof that 10% of water molecules form covalent bonds after freezing shows us that water uses this information when it freezes. Emoto's achievement, even without double-blind experiments, remains quite important in relation to the informational properties of water.

Natural snowflake, Wilson Bentley, 1925

Emoto snowflake obtained from natural water

One snowflake is natural, and the other is created by Emoto, indicating that the diversity in the water spectrum is not limitless.

Earthquake, Sofia, 4.0 Richter scale, November 15, 2008,
Dr. Ignatov, 2008©, Prof. Antonov's device©

This figure indicates the difference between the control sample and those taken on other days. Water molecules break the most energetic hydrogen bonds in water, as well as two peaks in the spectrum during a natural phenomenon. The study was carried out using the Antonov device. The biophysical result shows a decrease in the vitality of the body during an earthquake. During an earthquake, water cannot change its structure in the snowflakes in Emoto's lab. There is evidence of a change in the electrical conductivity of water during an earthquake.

In 1963, Tanzanian schoolboy Erasto Mpemba noticed that hot water freezes faster than cold water. This phenomenon is called the Mpemba effect. Although the unique property of water was noticed much earlier by Aristotle, Francis Bacon and Rene Descartes. The phenomenon has been proven many times over by a number of independent experiments. Water has another strange property. In my opinion, the explanation for this is as follows: the differential nonequilibrium energy spectrum (DNES) of boiled water has a lower average energy of hydrogen bonds between water molecules than a sample taken at room temperature. This means that boiled water needs less energy in order to begin to structure crystals and freeze.

The key to the structure of ice and its properties lies in the structure of its crystal. Crystals of all modifications of ice are built from water molecules H 2 O, connected by hydrogen bonds into three-dimensional mesh frames with a certain arrangement of hydrogen bonds. The water molecule can be simply imagined as a tetrahedron (pyramid with a triangular base). At its center is an oxygen atom, which is in a state of sp 3 hybridization, and at two vertices - by a hydrogen atom, one of the 1s electrons of which is involved in the formation of a covalent N-About connection with oxygen. The two remaining vertices are occupied by pairs of unpaired oxygen electrons that do not participate in the formation of intramolecular bonds, therefore they are called lone. The spatial shape of the H 2 O molecule is explained by the mutual repulsion of hydrogen atoms and lone electron pairs of the central oxygen atom.

The hydrogen bond is important in the chemistry of intermolecular interactions and is driven by weak electrostatic forces and donor-acceptor interactions. It occurs when the electron-deficient hydrogen atom of one water molecule interacts with the lone electron pair of the oxygen atom of the neighboring water molecule (О-Н…О). Distinctive feature hydrogen bond is relatively low strength; it is 5-10 times weaker than a chemical covalent bond. In terms of energy, a hydrogen bond occupies an intermediate position between a chemical bond and van der Waals interactions that hold molecules in a solid or liquid phase. Each water molecule in an ice crystal can simultaneously form four hydrogen bonds with other neighboring molecules at strictly defined angles equal to 109 ° 47 "directed to the vertices of the tetrahedron, which do not allow the formation of a dense structure when water freezes (Fig. 3). In ice structures I, Ic, VII and VIII this tetrahedron is regular. In the structures of ice II, III, V and VI, the tetrahedra are noticeably distorted. In the structures of ice VI, VII and VIII, two mutually crossing systems of hydrogen bonds can be distinguished. This invisible framework of hydrogen bonds arranges water molecules in the form of a grid, the structure resembling a hexagonal honeycomb with hollow internal channels.If the ice is heated, the grid structure is destroyed: water molecules begin to fall into the voids of the grid, leading to a denser structure of the liquid - this explains why water is heavier than ice.

Rice. 3. The formation of a hydrogen bond between four H 2 O molecules (red balls indicate central oxygen atoms, white balls indicate hydrogen atoms)

The specificity of hydrogen bonds and intermolecular interactions, characteristic of the structure of ice, is preserved in melt water, since only 15% of all hydrogen bonds are destroyed during the melting of an ice crystal. Therefore, the bond inherent in ice between each water molecule and its four neighbors ("short range order") is not violated, although the oxygen framework lattice is more diffuse. Hydrogen bonds can also be retained when water boils. Hydrogen bonds are absent only in water vapor.

Ice, which forms at atmospheric pressure and melts at 0 ° C, is the most familiar, but still not fully understood substance. Much in its structure and properties looks unusual. At the nodes of the crystal lattice of ice, the oxygen atoms of the tetrahedra of water molecules are arranged in an orderly manner, forming regular hexagons, like a hexagonal honeycomb, and hydrogen atoms occupy various positions on the hydrogen bonds connecting the oxygen atoms (Fig. 4). Therefore, there are six equivalent orientations of water molecules relative to their neighbors. Some of them are excluded, since the presence of two protons on the same hydrogen bond at the same time is unlikely, but there remains a sufficient uncertainty in the orientation of water molecules. This behavior of atoms is atypical, since in a solid matter all atoms obey the same law: either they are atoms arranged in an orderly manner, and then it is a crystal, or randomly, and then it is an amorphous substance. Such an unusual structure can be realized in most modifications of ice - Ih, III, V, VI, and VII (and, apparently, in Ic) (Table 3), and in the structure of ice II, VIII, and IX, water molecules are orientationally ordered. According to J. Bernal, ice is crystalline in relation to oxygen atoms and glassy in relation to hydrogen atoms.

Rice. four. Structure of ice of natural hexagonal configuration I h

Under other conditions, for example, in space at high pressures and low temperatures, ice crystallizes differently, forming other crystal lattices and modifications (cubic, trigonal, tetragonal, monoclinic, etc.), each of which has its own structure and crystal lattice (Table 3). ). The structures of ice of various modifications were calculated by Russian researchers, Doctor of Chemical Sciences. G.G. Malenkov and Ph.D. E.A. Zheligovskaya from the Institute of Physical Chemistry and Electrochemistry. A.N. Frumkin of the Russian Academy of Sciences. Ice modifications II, III and V remain for a long time at atmospheric pressure if the temperature does not exceed -170 °C (Fig. 5). When cooled to approximately -150 ° C, natural ice turns into cubic ice Ic, consisting of cubes and octahedrons a few nanometers in size. Ice I c sometimes also appears when water freezes in capillaries, which is apparently facilitated by the interaction of water with the wall material and the repetition of its structure. If the temperature is slightly higher than -110 0 C, crystals of denser and heavier glassy amorphous ice with a density of 0.93 g/cm 3 are formed on the metal substrate. Both of these forms of ice can spontaneously transform into hexagonal ice, and the faster, the higher the temperature.

Tab. 3. Some modifications of ice and their physical parameters.

Modification

Crystal structure

Hydrogen bond lengths, Å

Angles H-O-H in tetrahedra, 0

Hexagonal

cubic

Trigonal

tetragonal

Monoclinic

tetragonal

cubic

cubic

tetragonal

Note. 1 Å = 10 -10 m

Rice. 5. State diagram of crystalline ices of various modifications.

There are also high-pressure ices - II and III of trigonal and tetragonal modifications, formed from hollow acres formed by hexagonal corrugated elements shifted relative to each other by one third (Fig. 6 and Fig. 7). These ices are stabilized in the presence of the noble gases helium and argon. In the structure of ice V of the monoclinic modification, the angles between neighboring oxygen atoms range from 860 to 132°, which is very different from the bond angle in the water molecule, which is 105°47'. Ice VI of the tetragonal modification consists of two frames inserted into each other, between which there are no hydrogen bonds, as a result of which a body-centered crystal lattice is formed (Fig. 8). The structure of ice VI is based on hexamers - blocks of six water molecules. Their configuration exactly repeats the structure of a stable water cluster, which is given by the calculations. Ices VII and VIII of the cubic modification, which are low-temperature ordered forms of ice VII, have a similar structure with frameworks of ice I inserted into each other. With a subsequent increase in pressure, the distance between oxygen atoms in the crystal lattice Ice VII and VIII will decrease, as a result, the structure of ice X is formed, in which the oxygen atoms are arranged in a regular lattice, and the protons are ordered.

Rice. 7. Ice of III configuration.

Ice XI is formed by deep cooling of ice I h with the addition of alkali below 72 K at normal pressure. Under these conditions, hydroxyl crystal defects are formed, allowing the growing ice crystal to change its structure. Ice XI has a rhombic crystal lattice with an ordered arrangement of protons and is formed simultaneously in many crystallization centers near the hydroxyl defects of the crystal.

Rice. eight. Ice VI configuration.

Among the ices, there are also metastable forms IV and XII, whose lifetimes are seconds, which have the most beautiful structure (Fig. 9 and Fig. 10). To obtain metastable ice, it is necessary to compress ice I h to a pressure of 1.8 GPa at liquid nitrogen temperature. These ices form much more easily and are especially stable when supercooled heavy water is subjected to pressure. Another metastable modification - ice IX is formed during supercooling Ice III and essentially represents its low-temperature form.

Rice. 9. Ice IV-configuration.

Rice. ten. Ice XII configuration.

The last two modifications of ice - with monoclinic XIII and rhombic configuration XIV were discovered by scientists from Oxford (Great Britain) quite recently - in 2006. The assumption that ice crystals with monoclinic and rhombic lattices should exist was difficult to confirm: the viscosity of water at a temperature of -160 ° C is very high, and it is difficult for molecules of pure supercooled water to come together in such a quantity that a crystal nucleus is formed. This was achieved with the help of a catalyst - hydrochloric acid, which increased the mobility of water molecules at low temperatures. On Earth, such modifications of ice cannot form, but they can exist in space on cooled planets and frozen satellites and comets. Thus, the calculation of the density and heat fluxes from the surface of the satellites of Jupiter and Saturn allows us to assert that Ganymede and Callisto should have an ice shell in which ices I, III, V and VI alternate. At Titan, ice forms not a crust, but a mantle, the inner layer of which consists of ice VI, other high-pressure ices and clathrate hydrates, and ice I h is located on top.

Rice. eleven. Variety and shape of snowflakes in nature

High in the Earth's atmosphere at low temperatures, water crystallizes from tetrahedra, forming hexagonal ice I h . The center of formation of ice crystals is solid dust particles, which are lifted into the upper atmosphere by the wind. Needles grow around this embryonic microcrystal of ice in six symmetrical directions, formed by individual water molecules, on which lateral processes - dendrites grow. The temperature and humidity of the air around the snowflake are the same, so initially it is symmetrical in shape. As snowflakes form, they gradually sink into the lower layers of the atmosphere, where temperatures are higher. Here melting occurs and their ideal geometric shape is distorted, forming a variety of snowflakes (Fig. 11).

With further melting, the hexagonal structure of ice is destroyed and a mixture of cyclic associates of clusters is formed, as well as from tri-, tetra-, penta-, hexamers of water (Fig. 12) and free water molecules. The study of the structure of the formed clusters is often significantly difficult, since, according to modern data, water is a mixture of various neutral clusters (H 2 O) n and their charged cluster ions [H 2 O] + n and [H 2 O] - n, which are in dynamic equilibrium between with a lifetime of 10 -11 -10 -12 seconds.

Rice. 12. Possible water clusters (a-h) of composition (H 2 O) n, where n = 5-20.

Clusters are able to interact with each other due to the protruding faces of hydrogen bonds, forming more complex polyhedral structures, such as hexahedron, octahedron, icosahedron, and dodecahedron. Thus, the structure of water is associated with the so-called Platonic solids (tetrahedron, hexahedron, octahedron, icosahedron and dodecahedron), named after the ancient Greek philosopher and geometer Plato who discovered them, the shape of which is determined by the golden ratio (Fig. 13).

Rice. 13. Platonic solids, the geometric shape of which is determined by the golden ratio.

The number of vertices (B), faces (G) and edges (P) in any spatial polyhedron is described by the relation:

C + D = P + 2

The ratio of the number of vertices (B) of a regular polyhedron to the number of edges (P) of one of its faces is equal to the ratio of the number of faces (G) of the same polyhedron to the number of edges (P) emerging from one of its vertices. For a tetrahedron, this ratio is 4:3, for a hexahedron (6 faces) and an octahedron (8 faces) - 2:1, and for a dodecahedron (12 faces) and an icosahedron (20 faces) - 4:1.

The structures of polyhedral water clusters calculated by Russian scientists were confirmed using modern methods of analysis: proton magnetic resonance spectroscopy, femtosecond laser spectroscopy, X-ray and neutron diffraction on water crystals. The discovery of water clusters and the ability of water to store information are the two most important discoveries of the 21st millennium. This clearly proves that nature is characterized by symmetry in the form of exact geometric shapes and proportions characteristic of ice crystals.

LITERATURE.

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2. Shumsky P. A., Fundamentals of structural ice science. - Moscow, 1955b p. 113.

3. Mosin O.V., Ignatov I. Awareness of water as a substance of life. // Consciousness and physical reality. 2011, T 16, No. 12, p. 9-22.

4. Petryanov I. V. The most unusual substance in the world. Moscow, Pedagogy, 1981, p. 51-53.

5 Eisenberg D, Kautsman V. Structure and properties of water. - Leningrad, Gidrometeoizdat, 1975, p. 431.

6. Kulsky L. A., Dal V. V., Lenchina L. G. Water is familiar and mysterious. - Kyiv, Rodyansk school, 1982, p. 62-64.

7. G. N. Zatsepina, Structure and properties of water. - Moscow, ed. Moscow State University, 1974, p. 125.

8. Antonchenko V. Ya., Davydov N. S., Ilyin V. V. Fundamentals of water physics - Kyiv, Naukova Dumka, 1991, p. 167.

9. Simonite T. DNA-like ice "seen" inside carbon nanotubes // New Scientist, V. 12, 2006.

10. Emoto M. Messages of water. Secret codes ice crystals. - Sofia, 2006. p. 96.

11. S. V. Zenin and B. V. Tyaglov, Nature of Hydrophobic Interaction. Occurrence of orientational fields in aqueous solutions // Journal of Physical Chemistry, 1994, V. 68, No. 3, p. 500-503.

12. Pimentel J., McClellan O. Hydrogen connection - Moscow, Nauka, 1964, p. 84-85.

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14. Hobza P., Zahradnik R. Intermolecular complexes: The role of van der Waals systems in physical chemistry and biodisciplines. - Moscow, Mir, 1989, p. 34-36.

15. E. R. Pounder, Physics of Ice, transl. from English. - Moscow, 1967, p. 89.

16. Komarov S. M. Ice patterns of high pressure. // Chemistry and Life, 2007, No. 2, pp. 48-51.

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18. Fletcher N. H. The chemical physics of ice, Cambreage, 1970.

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ice crystals

atmospheric phenomenon

Type of precipitation

Winter artist painting with one color

frost

Crystalline condensate of air moisture

weather phenomenon

Gray hair on a tree

Blue, blue, lying on the wires (song)

A layer of ice crystals on a cooled surface

A thin layer of ice crystals formed by evaporation on a cooling surface

A thin layer of snow on a cooling surface

Ice crystals formed from water vapor in the air

. "stiff" dew

Russian refrigerator brand

A thin layer of snow formed due to evaporation

Precipitation

Blue couch potato on wires

. “and not snow, and not ice, but will remove trees with silver” (riddle)

white precipitation

Frost on the wires

rainfall on trees

Covers trees in winter

Winter clothes tree

snow dew

snow covered moisture

Winter raid on the fir trees

Snow-white precipitation

lacy hoarfrost

Snowfall

snow raid

winter raid

. "whiteness" on the trees

Winter precipitation

Envelopes the trees in winter

Congealed fumes

Blue couch potato (song)

frozen steam

Winter attire of trees

White winter fringe

Blue-blue lay down on the wires

. dew in winter

snow dew

Precipitation on the wires

In winter in the trees

Blue lay down on the wires

thin layer of snow

Snow on branches and wires

. "and the spruce through ... turns green"

Blue couch potato (song)

Silver wood finish

Precipitation in winter

Blue precipitation on the wires (song)

Another name for frost

Rime as a matter of fact

. "As you enter the threshold, everywhere ..."

Hoarfrost in a nutshell

Frost after a cold night

. "frost pile"

Almost snow

snow fringe

frozen dew

Almost the same as frost

Almost snow in the morning

Hoarfrost on the wires in a song

Winter fringe on the bushes

frozen steam

winter dew

Winter cover of bushes

. "gray hair" on the branches

. "frost fluff"

thin layer of ice

thin layer of snow

Winter "gray hair"

Winter cover of bushes

The one that lay on the wires

Ice on the branches

frost on the trees

Winter silver on the trees

Painting by Goncharova

What you have to tear off from the car in the fall

winter frost

frozen steam

atmospheric phenomenon

A thin layer of ice crystals formed by evaporation on a cooling surface

. "And the spruce through ... turns green"

. "As you enter the threshold, everywhere..."

. "Frost Pile"

. "Frosty Fluff"

. "frozen" dew

. Rosa in winter

. "gray hair" on the branches

. "Blue blue ... lay down on the wires"

. "and not snow, and not ice, but will remove trees with silver" (riddle)

. "Whiteness" on the trees

Winter "gray hair"

Frozen fumes, dampness in the air, which settles on objects that are colder than air, and freezes down on them, which happens after the return of severe frosts. From breathing, frost sits on the beard, collar. On the trees, thick hoarfrost, kurzha, flask. Frost on the fruits, sweaty dullness. Fluffy hoarfrost - to the bucket. Large hoarfrost, mounds of snow, deeply frozen ground, to grain production. Great frost throughout the winter, heavy summer for health. On the prophet Haggai and Daniel, frost, warm Christmas time, and December. On Gregory of Nikiy January) frost on haystacks - to a wet year. Hoarfrost, covered with frost; frosty; abundant frost. Frosty, frosty, but to a lesser extent. Ineel m. on (from) branches of trees broken by the weight of hoarfrost. Hoarfrost or frostbite, frostbite, frostbite?, to be covered with frost. The corners of the hut are frozen and frosty, numb

frozen dew

Blue-blue, lay down on the wires

. "Blue-blue ... lay down on the wires"

We have all heard about the unique properties of water many times. If the "colorless and odorless liquid" did not possess special qualities, life on Earth in its present form would be impossible. The same can be said about the solid form of water - ice. Now scientists have figured out another of its secrets: in a study just published, experts have finally determined exactly how many molecules are needed in order to get an ice crystal.

Unique connection

The list of amazing properties of water can be very long. It has the highest specific heat capacity among liquids and solids, the density of its crystalline form - that is, ice - is less than the density of water in the liquid state, the ability to adhere ("stick"), high surface tension - all this and much more allows life on earth as such.

Water owes its uniqueness to hydrogen bonds, or rather their number. With their help, one H 2 O molecule can "bond" with four other molecules. Such "contacts" are noticeably less strong than covalent bonds (a kind of "ordinary" bonds that hold together, for example, hydrogen and oxygen atoms in a water molecule), and breaking each hydrogen bond individually is quite simple. But there are a lot of such interactions in water, and together they noticeably limit the freedom of H 2 O molecules, preventing them from breaking away from their "comrades" too easily, say, when heated. Each of the hydrogen bonds itself exists for a tiny fraction of a second - they are constantly destroyed and re-created. But at the same time, at any moment, most of the water molecules are involved in interaction with their "neighbors".

Hydrogen bonds are also responsible for the unusual behavior of water during crystallization, that is, during the formation of ice. Icebergs floating on the surface of the ocean, a crust of ice in fresh water - all these phenomena do not surprise us, because we are used to them from birth. But if the main thing on Earth was not water, but some other liquid, then neither ice rinks nor ice fishing would exist at all. The density of almost all substances during the transition from a liquid to a solid state increases, because the molecules are more closely "pressed" against each other, which means that there are more of them per unit volume.

The situation is different with water. Up to a temperature of 4 degrees Celsius, the density of H 2 O grows in a disciplined manner, but when this boundary is crossed, it abruptly drops by 8 percent. The volume of frozen water increases accordingly. This feature is well known to residents of houses with pipes that have not been repaired for a long time or those who forgot low-alcohol drinks in the freezer.

The reason for the anomalous change in the density of water during the transition from a liquid to a solid state lies in the same hydrogen bonds. The crystal lattice of ice resembles a honeycomb, in the six corners of which water molecules are located. They are interconnected by hydrogen bonds, and their length exceeds the length of the "ordinary" covalent bond. As a result, there is more empty space between the molecules of solidified H 2 O than there was between them in the liquid state, when the particles moved freely and could come very close to each other. A visual comparison of the packing of the molecules of the liquid and solid phases of water is given, for example,.

The exceptional properties and special importance of water for the inhabitants of the Earth ensured her constant attention of scientists. It would not be a big exaggeration to say that the combination of two hydrogen atoms and one oxygen atom is the most carefully studied substance on the planet. Nevertheless, specialists who have chosen H 2 O as the subject of their interest will not be left without work. For example, they can always study how, in fact, liquid water turns into solid ice. The process of crystallization, leading to such dramatic changes in all properties, occurs very quickly, and many of its details are still unknown. After the release of the last issue of the magazine Science one less mystery: now scientists know exactly how many water molecules need to be put in a glass so that in the cold its contents turn into familiar ice.

different ice

The word "usual" in the previous sentence is not used for stylistic reasons. It emphasizes that we are talking about crystalline ice - the one with a honeycomb-like hexagonal lattice. Although such ice is customary only on Earth, a completely different form of ice prevails in the endless interstellar space, which on the third planet from the Sun is obtained mainly in laboratories. This ice is called amorphous, and it has no regular structure.

Amorphous ice can be obtained if liquid water is cooled very quickly (within milliseconds or even faster) and very strongly (below 120 kelvins - minus 153.15 degrees Celsius). Under such extreme conditions, H 2 O molecules do not have time to organize into an ordered structure, and water turns into a viscous liquid, the density of which is slightly greater than that of ice. If the temperature remains low, then water can remain in the form of amorphous ice for a very long time, but when it warms up, it changes into a more familiar state of crystalline ice.

Varieties of the solid form of water are not limited to amorphous and hexagonal crystalline ice - in total, more than 15 types of it are known to scientists today. The most common ice on Earth is called ice I h, but in the upper atmosphere you can also find ice I c, the crystal lattice of which resembles a diamond lattice. Other ice modifications can be trigonal, monoclinic, cubic, rhombic, and pseudorhombic.

But in some cases, a phase transition between these two states will not occur: if there are too few water molecules, then instead of forming a strictly organized lattice, they "prefer" to remain in a less ordered form. “In any molecular cluster, interactions on the surface compete with interactions inside the cluster,” Thomas Zeuch, one of the authors of the new work, an employee of the Institute of Physical Chemistry at the University of Göttingen, explained to Lente.ru. “For smaller clusters, it turns out to be more energetically favorable maximize the surface structure of the cluster rather than form a crystalline core. Therefore, such clusters remain amorphous.”

The laws of geometry dictate that as the size of the cluster grows, the fraction of molecules that appear on the surface decreases. At some point, the energy benefit from the formation of a crystal lattice outweighs the advantages of the optimal arrangement of molecules on the surface of the cluster, and a phase transition occurs. But when exactly this moment comes, scientists did not know.

A group of researchers working under the guidance of Professor Udo Buck (Udo Buck) from the Institute of Dynamics and Self-Organization in Göttingen managed to give an answer. Experts have shown that minimum number molecules that can form an ice crystal is 275 plus or minus 25 pieces.

In their study, the scientists used the method of infrared spectroscopy, modernized so that the output could distinguish between the spectra that give water clusters that differ in size by just a few molecules. The method developed by the authors gives the maximum resolution for clusters containing from 100 to 1000 molecules - namely, in this interval, as it was believed, lies the "threshold" number, after which crystallization begins.

Scientists created amorphous ice by passing water vapor mixed with helium through a very thin hole into a vacuum chamber. Trying to squeeze into a tiny hole, the water and helium molecules continuously collided with each other and in this crush lost a significant part of their kinetic energy. As a result, already “calmed down” molecules, which easily form clusters, got into the vacuum chamber.

By changing the number of water molecules and comparing the resulting spectra, the researchers were able to detect the moment of transition from the amorphous to the crystalline form of ice (the spectra of these two forms have very characteristic differences). The dynamics obtained by scientists was in good agreement with theoretical models, which predict that after passing through the "X point", the formation of a crystal lattice begins in the middle of the cluster and spreads to its edges. A sign that crystallization is imminent (again, according to theoretical studies) is the formation of a ring of six hydrogen-bonded molecules - this is what happens when the total number of molecules in the cluster becomes 275. A further increase in the number of molecules leads to a gradual growth of the lattice, and at the stage of 475 pieces, the spectrum of the ice cluster is already completely indistinguishable from the spectrum that gives ordinary crystalline ice.

"The mechanism of the phase transition from amorphous to crystalline state at the micro level has not yet been studied in detail," explains Zeuch. "We can only compare our experimental data with theoretical predictions - and in this case the agreement turned out to be remarkably good. Now, starting from the current results , we, together with theoretical chemists, will be able to continue the study of the phase transition and, in particular, we will try to find out how fast it occurs.

The work of Buck and colleagues falls into the "purely fundamental" category, although it also has some practical prospects. The authors do not exclude that in the future the technology they have created for studying water clusters, which makes it possible to see differences when several molecules are added, may also be in demand in applied fields. "In our article, we described all the key components of the technology, so that, in principle, it can be quite adapted to study clusters of other neutral molecules. However, the basic principles of the laser device were understood as early as 1917, and the first laser was created only in the 1960s ", - Zeuch warns against excessive optimism.