A 3D 12-ring zeolite with ordered 4-ring vacancies occupied by (H2O)2 dimers.

A germanate zeolite, PKU-14, with a three- dimensional large-pore channel system was structurally characterized by a combination of high-resolution powder X-ray diffraction, rotation electron diffraction, NMR, and IR spectroscopy. Ordered Ge4 O4 vacancies inside the [4(6) .6(12) ] cages has been found in PKU-14, in which a unique (H2 O)2 dimer was located at the vacancies and played a structure-directing role. It is the first time that water clusters are found to be templates for ordered framework vacancies.