Structure and thermal behaviour of ScK(C2O4)2(H2O)2 and InRb1−x(H3O)x(C2O4)2(H2O)2⋅0.5(H2O): Two members of a family of open-framework oxalates with isotypic helical structures and zeolite-like properties

Two new mixed oxalates with an open architecture, ScK(C2O4)2(H2O)2 (I) and InRb0.77(H3O)0.23(C2O4)2(H2O)2⋅0.5(H2O) (II), have been synthesised from precipitation methods at ambient temperature. They crystallize in hexagonal system, space group P6222P6222 (No. 180), Z=3Z=3, with the following unit-cell parameters for I: a=8.8667(2) Åa=8.8667(2) Å, c=11.4908(4) Åc=11.4908(4) Å, V=782.36(4) Å3V=782.36(4) Å3, for II: a=9.0148(3) Åa=9.0148(3) Å, c=11.4645(3) Åc=11.4645(3) Å, V=806.86(4) Å3V=806.86(4) Å3. The two structures belong to a family of isotypic helical anionic open-frameworks built from square antiprismatic coordinated metals and bischelating oxalates. The counter-cations K+ and Rb+/H3O+ are located in the tunnels of the framework. The thermal decomposition process has demonstrated zeolite-like properties associated with weakly-bonded water molecules located in the voids of the framework.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide