|Physical State||Granules, Crystals, Powder, solid|
is an organic compound with the formula [C2
and the IUPAC name of 1,4,7,10,13,16-hexaoxacyclooctadecane. The compound is a crown ether. Crown ethers coordinate some metal cations in their central cavity; 18-crown-6 displays a particular affinity for potassium cations. The synthesis of the crown ethers led to the Nobel Prize in Chemistry to Charles J. Pedersen.