Ask A Scientist Chemistry Archive

Question:
How were the noble gasses discovered?  How were the first compounds involving 
inert gases created?  What was the process, and what were the circumstances?
 
What were the structures of the resulting molecules?
Thank you.
Elizabeth Todis, Roosevelt Middle School.  Eugene, Oregon.
 
Answer 1:
If you can go to your library and get your hands on a "CRC Handbook of
Chemistry and Physics," it has a gold mine of info on exactly what you
were asking.  Look in the section entitled probably "Properties of Inorganic
compounds" or "The Elements."  There it gives when and how each element was
discovered (I read them personally, way to much to put here, but I will post
if you really want an abridged version).  It also gives what kind of
compounds are made from the element (in the noble gas case, in particular).
E-mail me if you want a posting.  I'll try to write something up.
-Joe Schultz
 
Answer 2:
As we all know, the "Noble gases" are, in general, chemically inert,
and are therefore useful to chemists for providing inert
atmospheres to prevent unwanted reactions of air-sensitive
compounds. In 1962, N. Bartlett made the compound [O2+][PtF6-]
and realized that Xe takes the same amount of energy to
ionize to Xe+ as O2 does to be ionized to O2+. So he made a
red solid which he believed as XePtF6. Since then most people have
come to believe that he really made [XeF+][PtF6-], an ionic salt.
Anyway, this seems to be the first time a compound was made which
chemically incorporated a rare gas element. Since then, a number
of other compounds have been made: XeF2, XeF4, XeF6, andf a number
of xenon flourocations (XenFm+ and anions (Xe_n F_m -).
There are also xenon oxides (XeO3, HXeO4-, HXeO6-, H2XeO6^2-)
and xenon oxofluorides (like XeO2F2). Finally, there are xenon
compounds with bonds to other elements (like Xe[N(SO2CF3)2]2).
One can obtain KrF2 by passing an electrical discharge through Kr and
F2 at -183 Celsius, as well as XeF2. Bo other molecular fluoride
(No other, that is) have been observed. There is limited
evidence for the existence of KrFe(CO)5+ in exotic circumstances.
No chemical compounds are known for Radon, which is hard to study
because it has a short half-life. Finally, it was recently shown
(last month!) experimentally that He@ exists as a bound molecule
at VERY VERY low temperatures, with a bond length of around 15
Angstroms (typical bond lengths of hydrocarbons are close to 1 A).
Source: Cotton and Wilkinson, Advanced Inorganic Chemistry. - topper