From: sbharris@ix.netcom.com(Steven B. Harris)
Newsgroups: rec.drugs.chemistry,sci.med,sci.chem,sci.med.nutrition
Subject: Re: phosphoric acid
Date: 21 Mar 1999 10:03:00 GMT

In <36F2BE84.68A62577@cs.uoregon.edu> Bret Wood
<bretwood@cs.uoregon.edu> writes:

>mskala@csc.UVic.CA wrote:
>
>> As for Xe, I've heard it referred to as an anaesthetic, and that
>> suggests some biological activity, although that doesn't make much
>> sense as it doesn't react with anything. I could have heard wrong, or
>> it could be that it does something "mechanical" like dissolving in your
>> blood and unbalancing other solution equilibria. (?)
>
>For a long time, it was thought that the "Inert Gasses" wouldn't form
>chemical compounds.  But, in fact there are some stable compounds of
>Xe.
>
>The first such compound was discovered in 1962.  It is XePtF6
>
>Since then, there have been a number of Xenon compounds synthesized.
>Xenon generally forms compounds with Flourine and Oxygen.
>
>Some examples:  XeF4, XeF2, XeO3.  XeO4 is another example, but unlike
>the previous examples, it is unstable.  Believe it or not, XeF4 is
>a stable solid at room temperature.
>
>Krypton and Radon also form compounds, but not as well as Xenon.
>
>So, unless Argon and Neon also have anesthetic properties, it is
>possible that Xenon is performing a chemical function, rather than
>a mechanical one.



   No, it isn't.  I'm well aware of xenon compounds.  All start with
xenon fluoride made from xenon and fluorine, the most reactive
oxidizing substance known (even the oxide, which BTW is explosive).
None of them are stable in water.  The idea that xenon forms chemical
compounds in water spontaneously is unlikely.

   The anaesthetic properties of gases go up in proportion to partial
pressure.  Even nitrogen causes narcosis and begins to act like nitrous
oxide at pressure, as it disolves in nerve membrane bilayers and causes
them to change properties.  It's a mechanical, not a chemical, effect.
 If you raise pressure still more you begin to squeeze nerve membranes
again from shear pressure stress, then the anaesthesia begins to
actually wear off.  tadpoles in water first go to sleep as you raise
pressure from N2O, then as pressure is raised still more, they wake up
and begin swimming again.  It's a biphasic effect-- impossible to
explain from chemistry alone.