Silicalite

It consists of tetrahedral silicon centers and two-coordinate oxides.

It is prepared by hydrothermal reaction using tetrapropylammonium hydroxide followed by calcining to remove residual ammonium salts.

It is useful because the material contains (SiO)10 rings that allow sorption of hydrophobic molecules of diameter 0.6 nm.

With the formula Si1−xTixO2, it consists of silicalite with Ti doped into some Si sites.

Unlike conventional polymorphs of titanium dioxide, the Ti centers in titanium silicalite have tetrahedral coordination geometry.