摘要
Davis等1988年首次合成出具有十八元环的大孔磷铝分子筛VPI-5,次年又以二正丙胺（DPA）和四丁基氢氧化铵（TBAOH）为导向剂合成出VPI-5分子筛.Crowder等根据结晶化学已知的键长、键角等数据,拟合出它的初结构,认为VPI-5分子筛晶体的对称性属六方晶系,空间群属C<sub>6</sub><sup>3</sup>v-P<sub>63</sub>cm. 从[001]方向俯视VPI-5,其骨架由六个6元环和十二个4元环构成。
Aluminophosphate-based molecular sieves VPI-5 were synthesized by hydrothermal crystallization using n-dibutylamine as a structure directng agent. The crystal structure of VPI-5 was determined by X-ray powder diffraction. The structural topographs are similar to those drawn by Cro-wder et al., but in the framework, the average bond lengths of T (1)-O, T(2)-O, T(3)-O and T(4)-O are 0.159, 0.163, 0.163 and 0.164nm respectively. This evidences that tha sites T(l), T(2), T(3) and T(4)are occupied disorderly by P and Al, although T(1), T(2) correspond to P and T(3), T(4) correspond to Al in Crowder's paper.
基金
国家自然科学基金
