While working on chemmacros I found I wanted to use some functionality which is currently provided by the package bohr. But since I only wanted part of the functionality I realised that the same was true for bohr: it needed the functionality but wasn’t originally designed to provide it. It made sense to extract said functionality into a package of its own, extended with further functioniality. Long story short: there’s a new package called elements which will be sent to CTAN once bohr is updated to use the new package. June 24th, 2015: elements has been sent to CTAN, bohr has been updated to v1.0.