Comments on: The Confusion of Registry Numbers on ChemSpider http://www.chemspider.com/blog/the-confusion-of-registry-numbers-on-chemspider.html Building Community for Chemists Fri, 10 Feb 2012 11:07:05 +0000 hourly 1 http://wordpress.org/?v=3.1.2 By: Getting a CAS Number from a PubChem CID at So much to do, so little time http://www.chemspider.com/blog/the-confusion-of-registry-numbers-on-chemspider.html/comment-page-1#comment-131968 Getting a CAS Number from a PubChem CID at So much to do, so little time Mon, 02 Feb 2009 06:07:33 +0000 http://www.chemspider.com/blog/?p=526#comment-131968 [...] to have multiple CAS numbers in PubChem and this problem has been discussed by Antony a number of times. Finally, given the fact that it might be possible that some arbitrary string matches the CAS [...] [...] to have multiple CAS numbers in PubChem and this problem has been discussed by Antony a number of times. Finally, given the fact that it might be possible that some arbitrary string matches the CAS [...]

]]> By: Getting a CAS Number from a PubChem CID « So much to do, so little time http://www.chemspider.com/blog/the-confusion-of-registry-numbers-on-chemspider.html/comment-page-1#comment-126608 Getting a CAS Number from a PubChem CID « So much to do, so little time Fri, 12 Dec 2008 02:50:30 +0000 http://www.chemspider.com/blog/?p=526#comment-126608 [...] to have multiple CAS numbers in PubChem and this problem has been discussed by Antony a number of times. Finally, given the fact that it might be possible that some arbitrary string matches the CAS [...] [...] to have multiple CAS numbers in PubChem and this problem has been discussed by Antony a number of times. Finally, given the fact that it might be possible that some arbitrary string matches the CAS [...]

]]> By: Deb Banville http://www.chemspider.com/blog/the-confusion-of-registry-numbers-on-chemspider.html/comment-page-1#comment-39505 Deb Banville Mon, 19 May 2008 17:02:37 +0000 http://www.chemspider.com/blog/?p=526#comment-39505 CAS RN's are assigned using strict business rules, however, few of us know what these rules are and how to apply them correctly. The phosphonic acid structures you drew appear to differ in their salts in some cases. The first structure without the salts is the correct structure for the CAS RN you gave (MF C6H20N2O12P4). It would have been easier to spot salt/parent compounds if the Molecular Formulas have the salts separate from their parent compounds, i.e. C6 H20 N2 O12 P4 . Na6. Better yet, avoid the RN's (outside of CAS databases) and rely on the structures themselves or a variety of representions like INCHI's or SMILEs that directly describe the molecule of interest. The INCHI type of representations can be searched using WIKI text searching capabilitites and will be as correct as the structure it was generated from! CAS RN’s are assigned using strict business rules, however, few of us know what these rules are and how to apply them correctly. The phosphonic acid structures you drew appear to differ in their salts in some cases. The first structure without the salts is the correct structure for the CAS RN you gave (MF C6H20N2O12P4). It would have been easier to spot salt/parent compounds if the Molecular Formulas have the salts separate from their parent compounds, i.e. C6 H20 N2 O12 P4 . Na6.

Better yet, avoid the RN’s (outside of CAS databases) and rely on the structures themselves or a variety of representions like INCHI’s or SMILEs that directly describe the molecule of interest. The INCHI type of representations can be searched using WIKI text searching capabilitites and will be as correct as the structure it was generated from!

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