(R,R)-Tartaric Acid vs meso-Tartaric Acid - Isomer Relationship

What is the relationship between (R,R)-Tartaric Acid and meso-Tartaric Acid?

(R,R)-Tartaric acid is chiral (optically active). meso-Tartaric acid has stereocenters but is achiral due to an internal mirror plane.

Molecule A(R,R)-Tartaric Acid (C₄H₆O₆)
Molecule Bmeso-Tartaric Acid (C₄H₆O₆)
Relationship Typemeso compounds
Difficultybeginner

Introduction

Both molecules have two chiral centers. But one is optically active and the other is not. Why?

Formula Comparison

Both have the formula C₄H₆O₆ with identical connectivity: HOOC–CHOH–CHOH–COOH.

Connectivity Analysis

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

Spatial Relationship

In (R,R)-tartaric acid, both centers have the same configuration. In meso-tartaric acid, one center is R and the other is S.

Chirality Check

The meso form has an internal mirror plane between C2 and C3 — the top half mirrors the bottom half. This makes it achiral despite having stereocenters. (R,R)-tartaric acid has no internal mirror plane and is chiral.

Classification

This pair demonstrates the meso concept: a molecule with stereocenters that is nonetheless achiral due to internal symmetry. The (R,R) form and the meso form are diastereomers of each other.

Side-by-side 3D comparison with sync rotation, difference highlighting, and guided classification.

Compare (R,R)-Tartaric Acid and meso-Tartaric Acid in 3D

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