Crystal structure of -xylene@silicalite-1.

The crystal structure of a highly loaded complex of silicalite-1 (SL-1) with eight mol-ecules of -xylene per unit cell has been solved by single-crystal X-ray diffraction. In the crystal, four symmetrical SiO·2CH subunits per unit cell are observed. The -xylene mol-ecules sit at two different positions within the SL-1 channels. The first mol-ecule is located at the inter-section of the sinusoidal and straight channels, while the second guest mol-ecule is positioned in the center of the double ten-membered ring (10-MR) of the sinusoidal channel.