The structure of MCM-48 determined by electron crystallography

The structure of the amorphous walls of the mesoporous material MCM-48 was investigated with a combination of high-resolution transmission electron mi croscopy and selected area electron diffraction, and the three-dimensional structure was reconstructed by electron crystallography. The crystals were well ordered over large areas as shown by the images and diffraction patter ns. It was firmly confirmed from Fourier transforms of thin areas that MCM- 48 belongs to the Ia3d space group and that the amorphous walls roughly fol low the gyroid surface (a minimal surface), but the wall thickness is not u niform.