Tuesday, January 18, 2011

Properties of Light /Heavy Water

Water – isotopic variations  
The usual natural water consists of nine stable isotope connections
            1H216O,              1H217O,             1H218O, 
            2D216O,              2D217O,             2D218O,
            1H 16O 2D,         1H 17O 2D,        1H 18O 2D
in which there are two stable isotopes of hydrogen - protium (1H) and deuterium (2D). Taking into account a radioactive isotope of hydrogen - tritium (3T ) -  the number of isotope variants of water molecules will equal to 18. Note: Oxygen has also a number of radioactive isotopes (from 12O up to 25O), so the total number of water molecule variations is much bigger. As we can see, the molecular weight of water can vary between 14 and 31 atomic weight units, however the stable molecules have weight from 18 to 22 units only. So in the future under “light water” we’ll assume 1H216O molecules when it’s molecular weight equals to 18.  There are 8 “heavy water” molecules, however in the future I’ll focus more attention on heavy/light molecule reparations where hydrogen 1H atoms are replaced with twice heavier 2D deuterium atoms.
By the way, internationally accepted water isotope standards actually are based on defining the deuterium content in the water molecules, too.
Water Isotope Standards are defining the isotopic composition of water. Here are the main standards :
  • VSMOWVienna Standard of Mean Ocean Water:
                      D/H     =   (155,76 ± 0,5) × 10-6   or  ≈ 156 ppm
                            18O/16O   =   (2005,2 ± 4,5) × 10-6  or  ≈  2005 ppm 
  • GISP – Water standard from Greenland ice:
                      D/H     =     (124,6 ± 0,5) × 10-6   or   ≈ 124,5 ppm 
  • SLAP (Standard Light Antarctic Precipitation) Water standard from Arctic ice:
                D/H    =      (90,5 ± 1,0) × 10-6      or      ≈ 90,5 ppm








 Some Physical Properties of Heavy Water
It’s well known that physical-chemical properties of heavy water are totally different from properties of usual water: boiling temperature of heavy water is +101,4°С, the freezing point equals to +3,81°С and it has 10% higher density.
Needs to note, that heavy water is probably fully Earth born product – in outer space it was not registered. Deuterium is formed from protium after it captured neutron from cosmic radiation. World Ocean, polar and mountain ice, atmospheric moisture are the main natural “factories” of deuterium production.



When autumn comes to northern regions, the water in rivers began cooling down. This process is accelerated under influence of permafrost. Finally the water density reaches its maximum value - at temperature slightly below 4oC. This is a critical moment while after it in some areas of the bottom zone loose underwater ice is intensively formed.
Unlike normal ice, it has no regular crystal lattice, it has a different structure. The crystallization centers of this ice can be rocks, snags, and various irregularities, not necessarily lying on the bottom and associated with permafrost. The loose ice is formed in deep rivers with calm laminar flow.
The underwater ice formation usually ends with the ice float to the surface, although at this time no other ice around. Underwater ice sometimes can be seen even in summer. The question arises: what kind of "water” is in the water, which changes its aggregate state when temperature in the river is too high to turn ordinary water into ice, so that, as physicists say, there was a phase transition?
It’s well known that loose frazil ice appears first and melts last. We can assume that loose ice has higher concentration of heavy water than usual ice. Only the presence of such concentrations may explain the proven fact that in winter in northern waters the percentage of deuterium is noticeably reduced. Polar waters, as it is shown by tests, are with low deuterium concentration too. Moreover, the tests have proved that the ice and  ice cover in high latitudes have higher deuterium content than the waters around them.  
Need to remember that heavy water is indistinguishable from normal, but its consumption inside the organism can cause severe poisoning. Not surprisingly, local people in high-latitude regions do not use river ice for cooking - only lake ice or snow.

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