Supertetrahedral sulfide crystals with giant cavities and channels

Although aluminosilicates and metal phosphates can form porous open-framewo rk materials such as zeolites, sulfide analogs usually form high-density ph ases because of the relatively small tetrahedral angle at sulfur atoms. One strategy to overcome this Limitation is to use tetrahedral clusters as the building blocks to achieve porous sulfide-based networks. The preparation and crystal structures of two indium sulfide open frameworks (ASU-31 and AS U-32) built of supertetrahedral clusters around organic template and water guests are described. ASU-31, based on the sodalite-tetrahedrite network, c ontains cavities 25.6 angstroms in diameter, and ASU-32, based on the tetra gonal CrB4 network, contains channels with a minimum diameter of 14.7 angst roms, The organic cations can be completely exchanged with sodium ions in a queous solution at room temperature without degradation of the crystals.