Comparison of conventional and synchrotron X-ray structure determinations of the adduct 1,2,4,5-tetrahydroxybenzene-2,5-dihydroxy-1,4-benzoquinone (1/1) and a conventional X-ray structure determination of 1,2,4,5-tetrahydroxybenzene monohydrate.

The X-ray structure of 1,2,4,5-tetrahydroxybenzene (benzene-1,2,4,5-tetrol) monohydrate, C6H6O4*H2O, (I), reveals columns of 1,2,4,5-tetrahydroxybenzene parallel to the b axis that are separated by 3.364 (12) and 3.453 (11) A. Molecules in adjacent columns are tilted relative to each other by 27.78 (8) degrees. Water molecules fill the channels between the columns and are involved in hydrogen-bonding interactions with the 1,2,4,5-tetrahydroxybenzene molecules. The crystal structure of the adduct 1,2,4,5-tetrahydroxybenzene-2,5-dihydroxy-1,4-benzoquinone (1/1), C6H6O4*C6H4O4, (II), reveals alternating molecules of 1,2,4,5-tetrahydroxybenzene and 2,5-dihydroxy-1,4-benzoquinone (both lying on inversion centers), and a zigzag hydrogen-bonded network connecting molecules in three dimensions. For compound (II), the conventional X-ray determination, (IIa), is in very good agreement with the synchrotron X-ray determination, (IIb). When differences in data collection temperatures are taken into account, even the displacement parameters are in very good agreement.