We added a few more structure representations that can be calculated from a structure identifier by the Chemical Identifier Resolver:
molecular weight and monoisotopic mass
If you use the IUPAC name representation for a structure identifier please read the following notice: we took great care during the implementation of the name index for this web service, however, we are aware of that it is far from perfect and has quite few errors in it. Unfortunately, these errors are not easy to to find if you have to deal with millions of names and their proper assignment to the correct chemical structure. If you find any mistakes, please tell us. Our plan is to improve the name index over the time but we are of course happy about any contributions helpful for this process. Thanks!