18‑Crown‑6‑Ether (CAS No. 17455‑13‑9; Chemical Formula: C₁₂H₂₄O₆) is a cyclic polyether composed of six ethylene oxide units. This crown ether selectively complexes with cations, especially potassium ions, making it valuable in phase-transfer catalysis, ion-selective electrodes, and coordination chemistry. It appears as a white crystalline solid with high purity (≥98%).