Normal, heavy and extra heavy water

      Until the XIX century, people thought water conventional chemical element. In 1805, Alexander von Humboldt and Joseph Louis Gay-Lussac found that water consists of molecules, each of which contains two atoms of hydrogen and one of oxygen, and it was thought that water - individual compound represented the only possible formula.

      In 1932, the world had spread sensation: than water normal, naturally there is also a heavy water. In such water molecules of hydrogen takes place its heavy isotope - deuterium. Heavy water opened American physicists Harald Urey and Elbert Osborne. In 1933, the American Herbert Lewis, together with Richard MacDonald first isolated it in pure form.

      In small amounts of heavy water constantly and everywhere present in natural waters, which from ordinary water can be distinguished only by physical characteristics. The heavy water molecule consists of hydrogen atoms is not easy - protium (1H), and its heavy isotope - deuterium (2D), which atom is heavier per unit protium, and molecular weight of the heavy water at 2 units higher than 20, but not at 18. Weight 10% denser than normal, a viscosity above 23%, boils at 101,42S freezes at + 3,8S. The content of heavy water in natural waters is not uniform. For example, in its closed reservoirs more as compared with usual water evaporates it less intensely.

        The heavy water is greater in areas with hot climates, on the ocean surface at the equator in the tropics. Heavy water condenses faster than light. Near the poles in the high southern latitudes (in the Antarctic) ocean waters noticeably "lighter" and have the lowest content of deuterium in the world. Just small proportion of deuterium in the ice of Greenland.

     Heavy water is naturally in small amounts - in millionths of a percent. Mostly its kind, whose composition is expressed by HDO. The world's oceans contain 1015 tonnes of HDO. Heavy water - a very important industrial raw material for nuclear power, effective moderator of fast neutrons. For example, 1 g of deuterium fusion decay gives 10 million. Times more energy than 1 g of carbon when burned.

          Heavy water negatively affects the vital functions of organisms; This occurs even when using ordinary natural water with a high content of heavy water.

      The experimental animals fed with water, 1/3 of which has been replaced by water composition HDO. After a short time began disorder of metabolism of animals destroyed kidneys. By increasing the proportion of heavy water animals died.

        The development of higher plants, heavy water and depressing; when watering them with water, half consisting of heavy water, growth stops.

Yet despite this, many bacterial cells, plants and algae can be adapted to grow on heavy water.

      DDW in the water stimulates the vital processes. When consuming water containing deuterium at 25% below normal pigs, rats and mice were given progeny more numerous and larger than usual, egg production rose twice as chickens, wheat matured earlier and gave higher yields. This can be explained by differences in the density and viscosity of heavy water, as well as its hydrophobic effect.

        Later, in clarifying the fractional composition of the water has been discovered T20 super-heavy water. It consists of hydrogen takes place its natural isotope, even heavier than deuterium. This tritium (T), which is in contrast to the deuterium it is radioactive, it is equal to the atomic mass of 3.

     Tritium originates in the upper atmosphere, where there are natural nuclear reactions. He is one of the products of neutron bombardment of the nitrogen atoms of cosmic radiation. Every minute, every square centimeter of the earth's surface fall 8- 9 tritium atoms.

      In small amounts extra-heavy (tritium) water enters the Earth in composition of precipitation. Throughout the Earth's hydrosphere there are only about 20 kg T20. Tritiated water is distributed unevenly in the continental waters of her more than in the oceans; polar ocean waters her more than equatorial. The properties of super-heavy water is still markedly different from the usual: boils at 104 ° C, 4-9 ° C when frozen, has a density of 1.33 g / cm3.

     superheavy water is used in thermonuclear reactions. It is easier to deuterium as very comfortable in the definition.

     The list does not end with the hydrogen isotopes tritium. In the laboratory, nuclear reactor artificially produced heavier isotopes 4H and 5H, is also radioactive. Scientists predict the existence of the water molecules that contain any of the five isotopes of hydrogen in any combination thereof.

      In nature, there are also the oxygen isotopes. In addition to the known oxygen 16O, there are two natural isotopes of oxygen - 17O and 18O. In natural waters, on average, for every 10 thousand atoms of the isotope 16O has to 4 atoms of the isotope 17O and 20 atoms of the isotope 18O.

      In terms of physical properties tyazhelokislorodnaya water differs from the less usual than tyazhelovodorodnaya. Get it mainly by distillation of natural water and use as a source of drugs labeled with oxygen.

There are also six artificially created isotopes of oxygen, they are short-lived and radioactive. Among them: 13O, 14O and 15O - light, 19O and 20O - heavy and super-heavy isotope - 24O produced in 1970.

     The existence of five hydrogen and oxygen isotopes nine says that isotope varieties of water can be 135. The bulk of natural water - over 99% - is protium water - 1H216O. Tyazhelokislorodnyh water is much smaller: 1H218O - tenths of a percent. 1H217O - hundredth of the total number of natural waters. Only millionths of a percent of heavy water D2O, in the form of heavy water 1HDO in natural waters already contain much more. Even rarer than D2O, and there are nine types of natural radioactive water containing tritium.

        Classical water should be considered 1H216O protium water in pure form, ie without any impurities remaining 134 isotope varieties. Although the content of protium water in nature far exceeds the content of all other species combined, net 1H216O in natural conditions do not exist, there are only a few specialized laboratories. It is very difficult to get through and stored with great caution. For clean 1H216O are very thin, multi-stage water purification or synthesized water from the source elements and 1H2 16O2, which preliminary carefully cleaned of isotopic impurities. This water is used in the experiments and processes requiring exceptional purity chemicals.

     protium water could be called light water, but clean 1H216O - a rarity. Working standard of light water is considered a mixture of varieties of water composition 1H216O, 1H217O and 1H218O, taken in the same ratio in which the air present in the corresponding isotopes of oxygen.

     The term "heavy water" in practice, also has no equivalent. Water, the formula D218O, actually replaced by a mixture of varieties of water with a constant part of the hydrogen (deuterium is here) and with the content of oxygen isotopes according to the isotopic composition of the air.

      The bulk of the water potential of the Earth is water, which do not get drunk, do not use in any industry, either in agriculture or in the home. 97.75% or 1,338 * 109km3 - is salt water oceans and seas. The remaining 2.25% - fresh water, but half of them - 24 * 106km3 - "conserved" in the form of giant ice caps of Antarctica, the Arctic, Greenland, the highest mountains in various regions of the Earth. Approximately the same amount of water - 23.4 * 106km3 - hidden deep in the earth's crust. This underground water.

        The amount of available fresh water is calculated in all the thousands of cubic kilometers. Most of all fresh water on the Earth's surface has been accumulated in the lakes -176.4 * 103km3. If you hold a moment for all the rivers of the world, it would have been, in their beds at the same time is 2120 km3 of water.

     The sources of many rivers, large and small, are in the marshes, which contain 10,300 km3 of fresh water. 13,000 tons of water is contained in the nearest to the surface layers of the atmosphere. At an altitude of up to 1 km the concentration of water vapor in the air an average of 2%. Here, perhaps, and all the water, which can realistically expect now mankind in the near future.