The article details the synthesis and structure characterization of MZS-1, a novel lithium-rich zincolithosilicate zeolite synthesized under high-pressure hydrothermal conditions. The material forms blade-shaped nanocrystals with a lamellar structure, making traditional X-ray diffraction challenging due to sub-micrometer crystal sizes and multiphase mixtures in the sample. We employed advanced 3D electron diffraction (3D ED) with precession and dynamical refinement to determine the atomic structure. MZS-1 features a framework of undulated silicate layers composed of fused six-membered rings connected via tetrahedral (Zn,Li)O₄ units, forming a 10-membered ring (10-MR) microporous structure. The resulting chemical formula is (SiO₂)₂Zn₀.₄₀₈LiO(OH)₂(Li,H)₂.₁₈₄, with lithium partially substituting zinc in the framework.
A weak superstructure (doubling the a-axis) was observed, attributed to Zn/Li ordering within the tetrahedral layers. Synchrotron powder X-ray diffraction confirmed lattice parameters (a = 8.58 Å, b = 14.12 Å, c = 4.97 Å, space group Ccc2), while thermogravimetric analysis and solid-state NMR revealed the presence of hydroxyl/water groups in pores and lithium’s role in the framework. The study highlights the potential of 3D ED for resolving complex, disordered structures in nanocrystalline materials.
Figure: SEM micrographs of the synthesized product at 145°C containing the new zincosilicate, (a) global view, (b) magnified view showing the main phase.