(2R,3R)-Tartaric Acid vs (2S,3S)-Tartaric Acid - Isomer Relationship

Introduction

Tartaric acid has three stereoisomeric forms. This pair shows the two that are mirror images of each other — the (R,R) and (S,S) enantiomers.

Formula Comparison

Both have the formula C₄H₆O₆ with identical connectivity: HOOC–CHOH–CHOH–COOH. Same formula, same bonding.

Connectivity Analysis

Each molecule has two chiral centers (C2 and C3), each bearing H, OH, COOH, and CHOH(COOH). The bonding sequence is identical.

Spatial Relationship

In the (2R,3R) form, both hydroxyl groups point the same way. In the (2S,3S) form, both point the opposite way. One molecule is the mirror image of the other.

Chirality Check

Both C2 and C3 are chiral centers. In the (R,R) form, both have R configuration. In the (S,S) form, both have S configuration. Every chiral center is inverted — the hallmark of enantiomers.

Classification

These are enantiomers — non-superimposable mirror images. They rotate plane-polarized light by equal amounts in opposite directions. Note: the third stereoisomer (the meso form with R,S configuration) is a diastereomer of both.

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