Synthesis, structure and properties with a chiral of CsHSi3O7, a layered silicate structure

摘要

The chiral layered silicate CsHSi3O7 has been synthesized by hydrothermal techniques, and its structure determined by single crystal X-ray diffraction. The compound crystallizes in the space group P2(1)2(1)2(1). The silicate single layer consists of both four- and three-connected SiO4 tetrahedra and may be considered as a member of a series of layer structures with the general formula (Si4O9)m(Si2O5)(n). Strong hydrogen bonds occur between the terminal OH- and O2- ions of neighboring layers. The Cs+ cations can be ion-exchanged by protons to give a phase of composition H2Si3O7 (.) H2O with a water molecule occupying the original Cs position, as confirmed by single crystal X-ray diffraction data. The water molecule in H2Si3O7 (.) H2O can be readily removed without collapse of the crystal structure. Both CsHSi3O7 and H2Si3O7. H2O show SHG (second harmonic generation) efficiencies comparable to that of quartz, and both are not phase-matchable materials. (C) 2004 Elsevier Inc. All rights reserved.