1,21-Henicosanediol.

In the molecular structure of the title compound, C(21)H(44)O(2), the hydrocarbon skeleton has an all-trans conformation. One of the terminal hydroxyl groups is also trans with respect to the skeleton, while the other is gauche. In the crystal structure, the molecules lie parallel to the b axis, forming layers with a thickness of b/2. The packing is similar to that in the smectic A phase of liquid crystals. These features are similar to those of the homologues with an odd number of C atoms, but different from those with an even number.