Hmm I found this in Nature about copernicium s symbol So was cyclopentadienyl a factor or not Do you have information about this It would be great if added to the WP article on copernicium because it would clear up all these misconceptions If it was a factor IUPAC s decision makes a lot of sense because Cp is still used If it wasn t I find it a lot harder to understand Granted cassiopeium was often used by German speaking chemists in the early 20th century but IIRC this usage is almost extinct now I may very well be wrong So yes I retract that IUPAC may well have been consistent although the WP article s omission of cyclopentadienyl makes it look as though they weren t