An open-framework silicogermanate regularly constructed from natrolite zeolite chains and Ge₉O₁₈(OH)₄ clusters

Area of Science:

• Materials Science
• Inorganic Chemistry
• Crystallography

Background:

• Open-framework materials are crucial for catalysis, gas storage, and separation.
• Developing novel structures with tailored properties remains a key challenge.
• Silicogermanates offer unique structural diversity compared to pure silica or Германия oxides.

Purpose of the Study:

• To synthesize and characterize a new open-framework silicogermanate material.
• To elucidate the unique structural features and building units of the novel material.
• To explore new avenues for designing advanced inorganic microporous crystalline materials.

Main Methods:

• Synthesis of PST-18 using tetramethylammonium fluoride as a structure-directing agent.
• Synchrotron single-crystal X-ray diffraction for precise structural determination.
• Analysis of the material's three-dimensional pore system and chemical composition (Si/Ge ratio).

Main Results:

• Successful synthesis of PST-18, a novel open-framework silicogermanate with Si/Ge ratio ~0.6.
• Discovery of a unique hybrid structure composed of ordered natrolite zeolite chains and Ge9O18(OH)4 clusters.
• Identification of a 3D pore system with large cuboid cavities and 8-ring windows, plus 7-rings with OH groups.

Conclusions:

• PST-18 represents a new class of hybrid inorganic microporous materials.
• The combination of zeolitic and non-zeolitic building units offers a novel strategy for materials design.
• This discovery opens new directions for expanding the structural diversity of crystalline microporous materials.