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Ion Hydration

  1. Sep 16, 2010 #1

    somasimple

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    Hi All,

    What are the average distance of a ion and a water molecule when it is hydrated.

    1/ for sodium?
    2/ potassium?

    Thanks.
     
  2. jcsd
  3. Sep 16, 2010 #2

    Borek

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    What's the context? Are you asked to estimate it? Or you just need the value?
     
  4. Sep 16, 2010 #3

    somasimple

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    I just need average values for sodium and potassium.
    Contexts:
    1/ with 1 water molecule until 4 water molecules (see picture for a sodium example).
     

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  5. Sep 16, 2010 #4

    Borek

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    Google "ionic radii in water". Just beware, as some of those listed can already take hydration into account.
     
  6. Sep 16, 2010 #5

    somasimple

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    Last edited by a moderator: Apr 25, 2017
  7. Sep 16, 2010 #6

    Borek

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    I don't have access, so can't tell you much. But my guess is that it should at least list sources of the radii used.
     
  8. Sep 16, 2010 #7

    somasimple

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    Click on figures and tables. There are many values.
    BTW, I may buy it.

     
  9. Sep 16, 2010 #8

    Borek

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    I can buy it as well, but I won't buy it just to spend money :tongue2:
     
  10. Sep 16, 2010 #9

    somasimple

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    I think the responses are in my previous message.
     
  11. Sep 16, 2010 #10

    alxm

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    No, that's a silly (to the extent of bordering on crankish) paper.

    And your question makes no sense. These ions do not bind consistently to any particular number of water molecules in liquid water, and the coordination structure is dependent on the coordination number. The K+-H2O distance can be anywhere between 2.5 and 3.5 Å, and that's dependent on temperature, etc. See, e.g. http://jcp.aip.org/resource/1/jcpsa6/v132/i12/p124503_s1" [Broken]. (Which, unlike the other, isn't indulging in numerology.)
     
    Last edited by a moderator: May 4, 2017
  12. Sep 17, 2010 #11

    somasimple

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  13. Sep 17, 2010 #12

    somasimple

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  14. Sep 17, 2010 #13

    somasimple

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    Last edited by a moderator: Apr 25, 2017
  15. Sep 17, 2010 #14

    alxm

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    What's your point? That you know how to use google scholar/chemfinder/isi? I do too.

    So if you've been reading these papers, why are you under the impression that hydration of an ion looks like the picture you posted?
     
  16. Sep 17, 2010 #15

    somasimple

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    1/ I was just asking for the relevance/quality of the papers.
    2/ The picture is very simplified. It is flat but it is very convenient to draw that way. It seems that the distances from oxygen to a ion is a bit farer than my trial.
     
  17. Sep 30, 2010 #16

    somasimple

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    It is said that distance from Oxygen atom and potassium atom is around 2.5, 2.65 Angstroms.
    Is it possible to find some example where this distance is far less and around 1.5 Angstrom?
     
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