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, c(6)H(6)O(4).H2O, (I), reveals columns of 1,2,4,5-tetrahydrox ybenzene parallel to the b axis that are separated by 3.364 (12) and 3.453 (11) angstrom. Molecules in adjacent columns are tilted relative to each ot her by 27.78 (8)degrees. Water molecules fill the channels between the colu mns and are involved in hydrogen-bonding interactions with the 1,2,4,5-tetr ahydroxybenzene molecules. The crystal structure of the adduct 1,2,4,5-tetr ahydroxybenzene-2,5-dihydroxy-1,4-benzoquinone (1/1), C6H6O4.C-6 H4O4, (II) , reveals alternating molecules of 1,2,4,5-tetrahydroxybenzene and 2,5-dihy droxy-1,4-benzoquinone (both lying on inversion centers), and a zigzag hydr ogen-bonded network connecting molecules in three dimensions. For compound (II), the conventional X-ray determination, (IIa), is in very good agreemen t with the synchrotron X-ray determination, (IIb). When differences in data collection temperatures are taken into account, even the displacement para meters are in very good agreement.