R/S Assigner
Find the stereocenter, rank its four groups, point the lowest one away from you, and trace 1 → 2 → 3. Clockwise is R, counterclockwise is S.
1 Choose a molecule
Examples: · · · ·
Every corner and end is a carbon. Tap a corner to change the atom. Drawings don't have wedges yet, so I build one mirror image; use Mirror image to see the other.
Your input doesn't say which mirror image, so I built one of them. Everything below is about the model on screen. Mirror image shows the other one.
2 Find the stereocenters
Tap each carbon that has four different groups, in the model or here.
3 Rank the four groups
Tap the groups from highest priority (1) to lowest (4).
How the tie was broken
4 Point group 4 away from you
Rank the groups first.
Shortcut: if 4 points toward you, trace anyway and flip your answer.
5 Trace 1 → 2 → 3
Tap group 1, then 2, then 3.
The trace controls are under the model.
6 Name it
Finish each stereocenter first.
This tool uses the atomic-number rules taught in Organic I. A few rare cases need extra rules it doesn't cover.