18-Crown-6 binds to a variety of small cations, using all six oxygens as donor atoms. Crown ethers can be used in the laboratory as phase transfer catalysts. Salts which are normally insoluble in organic solvents are made soluble by crown ether. For example, potassium permanganate dissolves in benzene in the presence of 18-crown-6, giving the so-called "purple benzene", which can be used to oxidize diverse organic compounds.
Various substitution reactions are also accelerated in the presence of 18-crown-6, which suppresses ion-pairing. The anions thereby become naked nucleophiles. For example, using 18-crown-6, potassium acetate is a more powerful nucleophile in organic solvents:
:[K(18-crown-6)]OAc  +  CHCHCl    →    CHCHOAc  +  [K(18-crown-6)]Cl
The first electride salt to be examined with X-ray crystallography, [Cs(18-crown-6)]·e, was synthesized in 1983. This highly air- and moisture-sensitive solid has a sandwich molecular structure, where the electron is trapped within nearly spherical lattice cavities. However, the shortest electron-electron distance is too long (8.68 Å) to make this material a conductor of electricity.