The SN1 reaction proceeds through a planar carbocation, which is attacked by the nucleophile on both sides, giving rise to a mixture of stereoisomers.
![stereochemistry-sn1 estereoquimica-sn1](/images/stories/organica-i/reacciones-sustitucion/sn1/estereoquimica/estereoquimica-sn1-01.png)
Stage 1. Dissociation of the substrate, forming the planar carbocation
![stereochemistry-sn1 estereoquimica-sn1](/images/stories/organica-i/reacciones-sustitucion/sn1/estereoquimica/estereoquimica-sn1-02.png)
Stage 2. Attack of the nucleophile on both sides giving rise to the formation of two enantiomers in equal proportion (racemic mixture).
![stereochemistry-sn1 estereoquimica-sn1](/images/stories/organica-i/reacciones-sustitucion/sn1/estereoquimica/estereoquimica-sn1-03.png)
The products formed are enantiomers and are obtained in equal amounts, since the two faces of the carbocation are indistinguishable for water.