A new layered silicogermanate, PKU-22, was hydrothermally synthesized under fluoride conditions using the tetraethylammonium (TEA⁺) cation as the structure directing agent (SDA). The crystal structure was determined by single crystal X-ray diffraction. Structure analysis reveals that PKU-22 is constructed by sti layers stacking along the [100] direction in an ···AAAA··· manner, with TEA⁺ cations occurring in the interlayer spaces and F^– anions residing within the layer and connecting to Ge atoms, which also act as the charge compensation species. In situ temperature-variable powder X-ray diffraction results indicated that PKU-22 could be transferred into a three-dimensional STI-type zeolite PKU-22a on heating. It is interesting that the TEA⁺ cations remain intact in the structure of the condensed product. Solid-state NMR, inductively coupled plasma atomic emission spectroscopy, thermogravimetric-differential scanning calorimetry, and carbon, hydrogen, and nitrogen elemental analyses were applied to aid the structure analysis of PKU-22 and illustrate its transformation. The scheme of the topotactic condensation of PKU-22 to PKU-22a is proposed.

中文翻译：

---

层状硅锗锗酸盐PKU-22的合成，表征及其在三维STI型沸石上的全位缩合

使用四乙基铵（TEA ⁺）阳离子作为结构导向剂（SDA），在氟化物条件下水热合成了一种新的层状硅锗锗酸盐PKU-22 。通过单晶X射线衍射确定晶体结构。结构分析表明，PKU-22由构成STI层一起在······AAAA方式[100]方向上层叠，用TEA ⁺在层间空间和F发生阳离子^-位于所述层内并连接到阴离子Ge原子，它也充当电荷补偿物质。原位随温度变化的粉末X射线衍射结果表明PKU-22可以转移到三维STI中型沸石PKU-22a加热。有趣的是，TEA ⁺阳离子在缩合产物的结构中保持完整。固态NMR，电感耦合等离子体原子发射光谱，热重-差示扫描量热法以及碳，氢和氮元素分析被用于辅助PKU-22的结构分析并说明其转化。提出了PKU-22向PKU-22a的全位缩合方案。