What is nitrogen, and how to warehouse it, when it’s in liquid form (Part 1 of 2).
The nitrogen atom has the number seven on the periodic table, and that means that there are 7 protons and 7 electrons to be found. Nitrogen is a small atom, because it only has two electron shells, while an atom can have 7 shells in total. Nitrogen is located in period two, and in group 15. Just because it’s so far to the right on the periodic table, it can be concluded that it holds tight to its five valence electrons, because they are so many. An atom becomes larger in size when it does not need to hold many external minus charges in place, and the nitrogen is the opposite. The element in question has a stronger nuclear charge and on the electronegativity placement we see that "N" attracts the electrons of other substances very effectively. Just for comparison's sake; Fluorine attracts electrons the most, and has a value of 4.0 on the Pauling scale. Most electropositive is Francium with a value of 0.7. On the same scale, nitrogen has the value 3.0.
Nitrogen can be used as an oxidizing agent (just think how close “N” is placed to “O” on the periodic table, and that both atoms are non-metals with similar properties), and a good example of it we see in this classical reaction: N2 + 3 H2 ---> 2 NH3, that is what happens when the industry produce ammonia (to get ammonium nitrate in next step) that can be used as a fertilizer. The oxidizing agent nitrogen is gaining electrons, and became reduced by hydrogen. How we usually produce liquid nitrogen is thanks to a cryogenic gas plant, which is an industrial facility that separates air during distillation processes. That is the source from where the very pure gas and liquid nitrogen product comes from, and the process is happening during very cold conditions. At room temperature nitrogen is always a gas. We have to have in mind that the melting point of N2 is -210 degrees Celsius, and the boiling point is -192 Celsius, and it will always be found in nature in gas form.
The company that purchases the product will receive product specific information about the purity of the liquid and pressure in the tanks or cylinders. If the consumption of nitrogen is not very big, then you buy it in dewars, that are non-pressurized small cans. Now let’s talk about different types of nitrogen. The isotopes that are stable (non-radioactive, and they are not spontaneously rearranging themselves because of too many neutrons to bear in the core) are nitrogen-14 (the most common, making up 99,6% of total natural nitrogen) and nitrogen-15, and they are being produced in the CNO cycle. That is a carbon-nitrogen-oxygen cycle that occurs in the stars, and when a type of “hydrogen fusion” happens, we get helium as the product. New fusions will occur on some helium also, and we will get carbon (life forms are made of mostly oxygen, carbon, hydrogen and nitrogen (3,2%)). Fourteen nitrogen radioisotopes are known. They behave like nitrogen do but they are short-lived.
Nitrogen-13 is an important radioisotope. It is used in positron emission tomography (PET) mainly of the reason that its half-life is long enough to fulfill its purpose at the hospital, and because it can tag ammonia molecules and other compounds in the body (depending on what part of the body the doctors are scanning) very effectively. Tracers coming in into the body from “13 N” are relatively small. The dose needed for the patient is normally 2 mSv, which is little compared with for example rubidium-82, when the dose often is 15 mSv. The radioactive atoms are giving off positively charged positrons, and when you combine one positron with one electron they destroy each other, and in that moment gamma rays will be detected. Doctors are tracking tracers in the human body (that was inserted at the hospital) to reveal the organs function in 3 dimensions. Many nitrogen isotopes are synthetically produced, and 13 N is one of them. These isotopes are ranging from 12 N - 23 N.
The pictures are borrowed from google.
https://www.sciencedirect.com/science/article/abs/pii/S2352492822011606#:~:text=The%20electrochemical%20nitrogen%20reduction%20reaction%20%28NRR%29%20catalyzes%20the,O%20under%20ambient%20conditions%20to%20form%20NH%203.
https://www.chemicalaid.com/tools/redoxreaction.php?equation=N+%2B+H+%3D+NH3
https://scienceatyourdoorstep.com/2020/10/19/what-happens-after-helium-fusion/
https://www.bing.com/videos/search?q=positron+emission+tomography+youtube&docid=608046195819833721&mid=11EEA5960DA26DF0009911EEA5960DA26DF00099&view=detail&FORM=VIRE
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