The hydrophobic and organophilic nature1 of silicalite may prove commercially important for the removal of organic compounds from waste water. The framework linkage of silicalite1 is topologically the same as that of synthetic zeolite ZSM-5 (ref. 2), a shape-selective catalyst3 capable of converting methanol into water and hydrocarbons useful in automobile engines4. The tetrapropylammonium (TPA) fluoride (F)-containing precursor to fluoride-silicate5 crystallizes from a hydrothermal system containing silica, TPA+ and F− ions. Destruction of the organic cation during heating in air gives fluoride-silicalite, a polymorph of silica with some properties similar to those of silicalite1,5. We show here how a TPAF complex in the precursor lies at the tetrahedral intersection of the 10-ring channels of a silica framework in a position consistent with a template scheme for crystallization6. There is not enough space to permit replacement of TPA by the tetra-n-butyl ammonium complex used in the synthesis of ZSM-11 (ref. 7) and its silica counterpart, silicalite-2 (ref. 8)

中文翻译：

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四丙基氟化铵-硅酸盐的晶体结构

硅沸石的疏水性和亲有机性 1 可能证明对于从废水中去除有机化合物具有重要的商业意义。硅沸石 1 的骨架连接在拓扑结构上与合成沸石 ZSM-5（参考文献 2）相同，后者是一种形状选择性催化剂 3，能够将甲醇转化为水和碳氢化合物，可用于汽车发动机 4。含四丙基铵 (TPA) 氟化物 (F) 的氟化物-硅酸盐前驱体从含有二氧化硅、TPA+ 和 F- 离子的水热系统中结晶出来。在空气中加热过程中有机阳离子的破坏产生氟硅石，这是一种二氧化硅的多晶型物，具有与硅沸石相似的特性1,5。我们在这里展示了前体中的 TPAF 复合物如何位于二氧化硅骨架的 10 环通道的四面体交叉处，其位置与结晶模板方案一致6。没有足够的空间让 TPA 被用于合成 ZSM-11（参考文献 7）及其二氧化硅对应物硅石-2（参考文献 8）的四正丁基铵络合物替代