Aggregated Chemistry and Quality – is ChemSpider a Good Representative?

29 Apr

In a recent blog PMR commented on the quality of ChemSpider while focusing appropriately on the issue of quality in aggregated datasets. He commented specifically on a search performed on Sodium Chloride and the records located shown here. His comment was that the third of these , the structure of Na2Cl2, was “rubbish”. PMR commented “There is little point in collecting 10 million structures if you cannot rely on any of them”. We’re struggling with the issue.

So here’s the question…is it rubbish? PMR commented that for data collections that  “…there is junk in the historical record. And there is junk in some of the links donated. That may be where the Na2Cl2 for sodium chloride came from.” But it’s not junk. It’s chemistry. The existence of Na2Cl2 microclusters has been reported (1).  The sodium chloride dimer is also on the NIST webbook  and indexed into PubChem as record cid=6914545.

PMR went on to comment “But Pubchem is not, and should not be, a data repository except for NIH data. But nor should any other organisation try to aggregate all the data. Whar we should do is pool the metadata (InChIs, names, etc.( in pubchem and develop links and searches to distributed repositories and datasets elsewhere.”. I love the vision!

Here’s the definition of what ChemSpider is trying to do from the What is ChemSpider page “There are tens if not hundreds of chemical structure databases and no single way to search across them. There are databases of curated literature data, chemical vendor catalogs, molecular properties, environmental data, toxicity data, analytical data and on and on. The only way to know whether a specific piece of information is available for a chemical structure is to have simultaneous access to all of these databases. Since many of these databases are for profit there is no way to easily determine the availability of information within these commercial or even in the open access databases. With ChemSpider the intention is to aggregate into a single database all chemical structures available within open access and commercial databases and to provide the necessary pointers from the ChemSpider search engine to the information of interest. This service will allow users to either access the data immediately via open access links or have the information necessary to continue their searches into commercially available systems. The question “is there specific information about my chemical” will be answered. Accessing the information may require a commercial transaction with the appropriate provider.”

Our intention is to do exactly as suggested “pool the metadata (InChIs, names, etc and develop links and searches to distributed repositories and datasets elsewhere.” It’s already started.

One comment…the molecular weight for Na2Cl2 in the record on ChemSpider IS incorrect. This is listed as a known bug . It’s fixed…we just need to calculate properties for 10 million compounds. It’s underway.


About tony

Antony (Tony) J. Williams received his BSc in 1985 from the University of Liverpool (UK) and PhD in 1988 from the University of London (UK). His PhD research interests were in studying the effects of high pressure on molecular motions within lubricant related systems using Nuclear Magnetic Resonance. He moved to Ottawa, Canada to work for the National Research Council performing fundamental research on the electron paramagnetic resonance of radicals trapped in single crystals. Following his postdoctoral position he became the NMR Facility Manager for Ottawa University. Tony joined the Eastman Kodak Company in Rochester, New York as their NMR Technology Leader. He led the laboratory to develop quality control across multiple spectroscopy labs and helped establish walk-up laboratories providing NMR, LC-MS and other forms of spectroscopy to hundreds of chemists across multiple sites. This included the delivery of spectroscopic data to the desktop, automated processing and his initial interests in computer-assisted structure elucidation (CASE) systems. He also worked with a team to develop the worlds’ first web-based LIMS system, WIMS, capable of allowing chemical structure searching and spectral display. With his developing cheminformatic skills and passion for data management he left corporate America to join a small start-up company working out of Toronto, Canada. He joined ACD/Labs as their NMR Product Manager and various roles, including Chief Science Officer, during his 10 years with the company. His responsibilities included managing over 50 products at one time prior to developing a product management team, managing sales, marketing, technical support and technical services. ACD/Labs was one of Canada’s Fast 50 Tech Companies, and Forbes Fast 500 companies in 2001. His primary passions during his tenure with ACD/Labs was the continued adoption of web-based technologies and developing automated structure verification and elucidation platforms. While at ACD/Labs he suggested the possibility of developing a public resource for chemists attempting to integrate internet available chemical data. He finally pursued this vision with some close friends as a hobby project in the evenings and the result was the ChemSpider database ( Even while running out of a basement on hand built servers the website developed a large community following that eventually culminated in the acquisition of the website by the Royal Society of Chemistry (RSC) based in Cambridge, United Kingdom. Tony joined the organization, together with some of the other ChemSpider team, and became their Vice President of Strategic Development. At RSC he continued to develop cheminformatics tools, specifically ChemSpider, and was the technical lead for the chemistry aspects of the Open PHACTS project (, a project focused on the delivery of open data, open source and open systems to support the pharmaceutical sciences. He was also the technical lead for the UK National Chemical Database Service ( and the RSC lead for the PharmaSea project ( attempting to identify novel natural products from the ocean. He left RSC in 2015 to become a Computational Chemist in the National Center of Computational Toxicology at the Environmental Protection Agency where he is bringing his skills to bear working with a team on the delivery of a new software architecture for the management and delivery of data, algorithms and visualization tools. The “Chemistry Dashboard” was released on April 1st, no fooling, at, and provides access to over 700,000 chemicals, experimental and predicted properties and a developing link network to support the environmental sciences. Tony remains passionate about computer-assisted structure elucidation and verification approaches and continues to publish in this area. He is also passionate about teaching scientists to benefit from the developing array of social networking tools for scientists and is known as the ChemConnector on the networks. Over the years he has had adjunct roles at a number of institutions and presently enjoys working with scientists at both UNC Chapel Hill and NC State University. He is widely published with over 200 papers and book chapters and was the recipient of the Jim Gray Award for eScience in 2012. In 2016 he was awarded the North Carolina ACS Distinguished Speaker Award.
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Posted by on April 29, 2007 in Quality and Content


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