# Confused about inversions in $S_N2$ Reaction

I just learned that in $$S_N2$$ reaction there is an inversion of configuration. I thought that it is a change of $$R$$ to $$S$$ and vice-versa. But that is wrong as mentioned in this answer.

While I was referring to more sources I saw this.

Here it is mentioned that $$S$$ to changes to $$R$$. Shouldn't that be wrong as absolute configurations do not change?

EDIT: I solved a few problems and I think that $$R$$ to $$S$$ (and vice versa) inversion takes place when the attacking nucleophile is having the same priority (according to CIP rules) as the leaving group. Is my logic correct ?

• Hey there, you are correct. The assumption is that the nucleophile and leaving group have the same priority. – Michael Lautman Aug 26 '19 at 19:37
• @MichaelLautman Thanks! – Deepam Sarmah Aug 27 '19 at 2:29