MINERALOMIMETIC CRYSTAL STRUCTURES OF CN-LINKED CADMIUM COMPLEXES. T. Iwamoto, Department of Chemistry, College of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153, Japan

Polymeric structures of cadmium cyanide and polycyanopolycadmates give a number of CN-linked mineralomimetic crystal structures like pyroxene, clays, H- and L-cristobalite, H-tridymite, zeolites, rutile, beryl, pyrite, etc., with or without guest molecules accommodated in inter- or intralayer space in 2D structures, or in cavities in 3D structures. The Cd atoms in the mineralomimetic structures take the positions corresponding not only to tetrahedral Si but also octahedral Fe, Mg, Ti, etc. The Cd-CN-Cd span longer than Si-O-Si or Si-O-M generates a more voluminous void space in the mineralomimetic latticework than in real minerals so that guest molecule or bulky secondary ligand is required to stabilise the latticework structure. In other words the guest or the ligand plays a role of template to stabilise the mineralomimetic structure. The zeolite-like 3D host of [Cd₃(CN)₇]^- gives isomorphous clathrates of C₆H₆, PhMe, o- and m-C₆H₄Me₂, and PhEt of Pnam space group but the clathrates belong to P6₃/mmc and Pa for p-C₆H₄Me₂. Involvement of imidazole (imH) as a secondary ligand at octahedral or tetrahedral Cd in the host structures affords zeolite-like C₆H₆ and PhMe, beryl-like m-C₆H₄Me₂, rutile-like pC₆H₄Me₂, and clay-like PhEt guest clathrates. Silica-like Cd(CN)₂ host gives polymorphs similar to H- and L-cristobalite and H-tridymite depending upon the geometry of guest molecule. A pyrite(FeS₂)-like array of octahedral Cd²⁺ and [Cu₂(CN)₇]^5- isostructural to pyrosilicate-like [Cd₂(CN)₇]^3- is observed in H₃[Cd{Cu₂(CN)₇} ].14H₂O together with a rutile(TiO₂)-like array of hydrogen-bonded water molecules, 12H₂O ring like Ti⁴⁺ and 2H₂O like O^2-.