I have question about graphene.
When you have the graphene lattice two types of atoms can be distinguished, let's call them type A and B.You can draw a unit cell that has the shape of a parallelogram. It contains exactly one of each type of atoms. There is then an inversion symmetry center between atom of type A and atom of type B.
I thought that I understood what an inversion symmetry center was. I thought it was a point and if you move the particles in straight lines through those points you can get the original structure back.
But why does this work for graphene. If you exchange A and B, then you have a different unit cell, right?