A Short Introduction to ChemSpider

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[thechemist144]

@shariat2 I think there are 3 factors to consider:

1. Elements have a discrete mass & there are restrictions around how they combine. I would suggest that certain masses can result from a larger number of permutations than others.

2. Research is often focused on certain types of chemistry - thereby focusing interest on certain areas of chemical space.

3. A database contains only a subset of all known/published compounds adding a further filter.

Please email us with further questions.

[thechemist144]

@shariat2 Just to follow up on your query; for a number of reasons it is likely that many general chemistry databases will tend to have a large proportion of results in the mass range ~220-350 Da so I would expect that there will be a large number of hits for this query.

Without knowing the exact logic behind your query it is difficult to provide relevant advice. I would usually suggest that if you have a mass to 4 d.p. you pick a +/- value of no more than 0.005 Da (ie a range of 0.01)

[shariat2]

Thank you very much. that is great then. Another thing that seems confusing to me is; if I search 363.1040 Da+-0.1 i find 69543 hits. I get more or less the same number of hits in this mass region but for 363.6815 I just get 6 hits. Would it be just the fact or some searching error?

[thechemist144]

@shariat2 Every record in ChemSpider corresponds to a different (unique) chemical structure, therefore there will be no duplicates in the results that you obtained. However, you may have several results for records that have the same atom connectivity, but differ according to the configuration of one or more sterocentres.

[shariat2]

Hi, when I search for the mass 335.1130 plus minus 0.1 Da I get 61246 hits from chemspider. Is this real or there some structures reapeated in the serach result?

[jjkul1]

@thechemist144 I see your point and it is very valid. But I would like this feature to be consolidated with wikipedia. Merging the databases will ensure everyone uses and collaborates on chemistry under one roof.

[thechemist144]

@jjkul1 Wikipedia (WP) is a useful resource. I'd make 2 points:

1. At this time there are ~30,000 chemical compound articles in WP. ChemSpider has over 26M records - these include newly reported or obscure molecules, WP's mandate as an encyclopedia means it will not cover these.

2. The only way to find an article in WP is to search by name - this requires you to know the name of the cmpd & that this name is in the correct article. ChemSpider allows you to search by drawing a chemical structure

[jjkul1]

or we can just use wikipedia.

[Reqrezentin]

Excellent!!!