Where a lone pair from your nucleophile overlaps with the sigma* orbital of your leaving group. Nonetheless, this move does not provide the identical sensitivity to steric hindrance because the SN2 reaction, as we've been about to see. The system generally starts with addition of a nucleophile followed by elimination https://johnnyghjnp.get-blogging.com/38193656/the-2-minute-rule-for-solution-bromure-de-potassium