Re: S/W: Periodic Table Browser

[Robert Hopcroft <hopcroft@uswest.net>]

Tim Wilson wrote:

> On Fri, 25 Jun 1999, Kyle Burton wrote:
>
> > How would you store the data?  It's not a flat type of heirarchy...it's
> > not even like a grid.  I'm no chemist, but if you have 3Xs 4Ys and 3Zs,
> > isn't it possible that you might have 2, or more different compounds
> > that contain the same number/type of elements, but just with a different
> > structure?  Therefore different compunds?  I am not just referring to
> > the right/left handed types of molecules, but am imagining wholly different
> > chemicals.
>
> Ahh yes. Now we're having some fun. :-) I've got to put that chemistry
> degree to good use now.
>
> Compounds that have the same number and types of atoms, but different
> chemical structures are called isomers. Usually their chemical properties
> are similar, but not necessarily. You can also consider materials like
> graphite, coal, and diamond. All three are pure carbon, but completely
> different structures and obviously different properies.

First Kyle and Georges welcome to the list. Next, I'll try to add to what Tim
and others have said and yes Tim it is fun. Every chemical compound is uniquely
named. For example, 2,2-dimethylbutane is a butane molecule with the two
hydrogen atoms on the second carbon replaced by methyl groups. Now you're going
to say, "Why isn't it 1,1,1-trimethylpropane". Because one starts with the
longest carbon chain, which in this case is 4 and thus butane. Now on to X3Y4Z3.
This is not a bad idea. By first collecting the total number of each of the
elements you have narrowed the search to a set of compounds. Now you can try to
narrow the search using information on how the the elements were originally
grouped. This is just like a search on the web. The better the initial
specification the more precise the search and like on the web offer up the
compounds left to the user to chose from. I,m sure we can grind through this
without any trouble. Graphite, coal and diamond! Now we can get into
crystallography and many other things. But that's for another day.

Bob