Host-guest symmetry and charge matching in two germanates with intersecting three-dimensional channels

Two germanates reported here illustrate important effects of host-guest symmetry matching (or mismatching) on the host framework symmetry, the ordering of extraframework species, and the coordination number of germanium. For a strong structure-directing agent, the symmetry of the host framework is dictated by the symmetry of the ordered guest molecules, whereas for a relatively weaker structure-directing agent, the siting of guest molecules must conform to the symmetry of the host framework through specific molecular conformation or multiple orientations.