Microporus Material Investigation at ChemMatCARS
February 2003
Jeffrey E. Post (Smithsonian Institution- Sprague Fund), Peter J. Heaney (Penn State- NSF EAR01-25908 and PSU Center for Environmental Chemistry and Geochemistry) and Christopher L. Cahill (George Washington University) have used the microcrystallography facility at the ChemMatCARS synchrotron resource in their investigation of microporous materials.
Microporous manganese oxide minerals act as important chemical controls in soils, sediments and associated water systems. Further, their synthetic analogs are valued for their catalytic, ion exchange, electrochemical and adsorption properties.
Our efforts have focused on detailed structural characterization of octahedral molecular sieve (OMS) compounds; materials with frameworks built from edge-shared MnO6 octahedra. The structure of woodrufite (right) has recently been determined from a microcrystal and shown to have the largest tunnel structure to date in this system: 4 x 3 MnO6 octahedra.
Woodrufite: Zn2.8Mn14O28 ยท 9.5H2O C2/m
a = 24.687(5)Å, b = 2.8467(7)Å
c = 9.575(3)Å, β=94.228(5)°
Crystal Size: 2 x 2 x 50 μm
4 x 3 OMS