Figure 1. Octahedral molecular sieves (OMSs) and octahedral layered (OL) materials. Metal-oxygen octahedral coordination polyhedra are shown schematically. Tunnel dimensions for the molecular sieves (top) are measured diagonally, and interlayer spacings for the layered materials (bottom) are measured perpendicular to the layers. OMS-1 has a 3 × 3 tunnel structure, and OMS-2 has a 2 × 2 tunnel structure. EX indicates exchangeable cations. Return to article