1,17-Diphenyl-2,4,6,8,10,12,14,16-octa­oxahepta­deca­ne

The title compound, C₂₁H₂₈O₈, crystallizes with two independent mol­ecules, each with a crystallographic twofold axis passing through the central CH₂ group. The two mol­ecules have different orientations of the terminal benzyl groups. The average C—O bond length in the polyoxymethyl­ene helix, corrected for librational motion, is 1.419 Å. The mol­ecules are connected into layers by inter­molecular C—H...O and C—H...π(phenyl) inter­actions.