What I've understood about chirality and elements of symmetry:
A molecule that is not superposable on its mirror image is said to be chiral.
Plane of symmetry: An imaginary plane cutting a compound into two symmetric halves. Any compound possessing it is achiral, so any compound without it is chiral?
Axis of symmetry: I have never spent so long trying to understand a concept. An axis of symmetry is an imaginary axis around which by rotating through a minimum angle of rotation, the original compound is obtained.
1. Any compound, be it chiral, achiral or dissymmetric, can have an AOS.
2. You cannot say a compound is achiral just because it has an AOS.
3. Unless, I just had a thought. If on rotation it gives the same compound, making it superposable with the original, thereby making it achiral.
However, wouldn't all compounds (chiral or achiral) on rotation through a particular degree give back the same compound? Please tell me if everything I've mentioned is right.