I understand how and that the R,S and R,R stereoisomers are different. But I don’t see why the R,R and S,S compounds are stereoisomers and not meso compounds with each other. Online it says that these two compoundsare different stereoisomers, but I don’t see why they are not identical. I went on...

Does norbornene have a plane of symmetry? Is norbornene achiral or chiral? I think norbornene is chiral since there is a double bond on the only one side. Thus, there is no plane of symmetry. The answer in the book is that it is achiral and has a plane of symmetry. How so?