Designing a new intercalation compound based a van der Waals type of layered Bi-based compound

In order to develop a new intercalation compound, Ag-I incorporated Sr_1.5Bi_7.5O_12.75, in which good two-dimensional cationic conduction would be expected, whether two kinds of guest atoms of Ag and I were intercalated into a van der Waals type of layered Sr_1.5Bi_7.5O_12.75 or not was investigated in various reaction systems. It was possible to synthesize such a new intercalation compound in the following stepwise process: the host was first allowed to react in a solid-gas system with vaporized iodine and then in a solid-solid system with metallic silver. Chemical composition of the resulting intercalation compound was Ag : I : Sr_1.5Bi_7.5O_12.75 = 0.7 : 1.5 : 1 in molar ratio. The c axis of the host was expanded by ca. 1 nm in the doubly intercalation, while the a axis was little changed. Calculation of one-dimensional electron density along the c-axis direction gave a structural information that both the guest atoms were located in the van der Waals spacings sandwiched by the host layers. In addition, it was suggested that the guest composition was controllable with the synthetic parameters.