12 Crown 4

12-Crown-4, also called 1,4,7,10-tetraoxacyclododecane and lithium ionophore V, is a crown ether with the formula C₈H₁₆O₄. It is a cyclic tetramer of ethylene oxide which is specific for the lithium cation. Its point group is S₄. The dipole moment of 12-crown-4 varies in different solvent and under different temperature. Under 25 °C, the dipole moment of 12-crown-4 was determined as 2.33 ± 0.03 D in cyclohexane and 2.46 ± 0.01 D in benzene.