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Specialty Chemistry Forums => Citizen Chemist => Topic started by: billnotgatez on March 31, 2014, 11:50:35 AM

Title: Anhydrous Sodium thiosufate Puzzle
Post by: billnotgatez on March 31, 2014, 11:50:35 AM
I am reading about Sodium thiosulfate on WIKI and marveling at the various pictures of the structure.

http://en.wikipedia.org/wiki/Sodium_thiosulfate
http://en.wikipedia.org/wiki/File:Sodium-thiosulfate-3D-vdW.png

Ball-and-stick model of part of the crystal structure of anhydrous sodium thiosufate Na2[S2O3].
http://en.wikipedia.org/wiki/File:Sodium-thiosulfate-xtal-3D-balls.png

Connecting to the link for CAS number 7772-98-7 I am transported to
http://www.commonchemistry.org/ChemicalDetail.aspx?ref=7772-98-7
and I observe the picture of the structure.

I go back and look at WIKI smiles entry and get
[Na+].[Na+].[O-]S([O-])(=O)=S
which produces the picture
[Na+].[Na+].[O-]S([O-])(=O)=S

I go to
http://www.emolecules.com/
and search for
CAS number 7772-98-7  which I assume is Sodium thiosulfate anhydrous and get the following choices

choice 1
[O-]SOS[O-].[Na+].[Na+]
choice 2
[O-]S(=S)(=O)[O-].[Na+].[Na+]
choice 3
O=S=S(=O)=O.[Na][Na]
choice 4
[O-]S(=O)(=O)[S-].[Na+].[Na+]

It seems to me that choice 1 and choice 3 are different from all the other images I looked at and I am puzzled.






Title: Re: Anhydrous Sodium thiosufate Puzzle
Post by: Borek on March 31, 2014, 12:05:46 PM
Quote from: billnotgatez on March 31, 2014, 11:50:35 AM
[Na+].[Na+].[O-]S([O-])(=O)=S

Quote
[O-]S(=S)(=O)[O-].[Na+].[Na+]

Quote
[O-]S(=O)(=O)[S-].[Na+].[Na+]

These three are more or less equivalent (and close to reality, with a central S atom, surrounded by 4 others). Charge is not assigned to any particular atoms, you can think about these images as about resonance structures.
Title: Re: Anhydrous Sodium thiosufate Puzzle
Post by: billnotgatez on April 05, 2014, 02:09:45 AM
When I do the pentahydrate version
.O.O.O.O.O.[Na+].[Na+].[O-]S([O-])(=O)=S
I get using smiles
.O.O.O.O.O.[Na+].[Na+].[O-]S([O-])(=O)=S

but how do I get what  I want using smiles (below is gif not smiles)

Title: Re: Anhydrous Sodium thiosufate Puzzle
Post by: sjb on April 05, 2014, 03:25:43 AM
There's no real control over the depiction, short of perhaps moving the constituents around. Compare

.O.O.O.O.O.[Na+].[Na+].[O-]S([O-])(=O)=S
.O.O.O.O.O.[Na+].[Na+].[O-]S([O-])(=O)=S

to

O.O.O.O.O.[Na+].[O-]S([O-])(=O)=S.[Na+]
O.O.O.O.O.[Na+].[O-]S([O-])(=O)=S.[Na+]