ERS-18: A new member of the NON–EUO–NES zeolite family

ERS-18, a new small pore high silica zeolite, was synthesized using 6-azonia-spiro-[5,5]-undecane hydroxide as structure directing agent. Its crystal structure was determined ab initio by using high-resolution synchrotron X-ray powder diffraction data and the zeolite-dedicated software FOCUS. ERS-18 shows orthorhombic symmetry (s.g. Fmmm) setting with unit cell parameters: a=34.989, b=13.667 and c=22.559Å. The values of b and c parameters are in common with zeolites of the NON–EUO–NES family (IZA codes for nonasil, EU-1, and NU-87, respectively); within this group the a parameter, corresponding to the layer stacking direction, varies from ∼15.0 (NON) to ∼20.0 (EUO), to ∼25.0Å (NES). Therefore, ERS-18 can be regarded as a new member of this family having the longest stacking parameter (i.e. ∼35.0Å) reported so far. The ERS-18 framework is characterized by the presence of 8-ring channels (crystallographic free dimensions: 3.1×2.5Å) running along the [010] direction and supercages delimited by 12-rings (crystallographic free dimensions: 6.1×5.2Å, cross section; 18.4Å, depth) aligned along [100] and off the 8-ring channels.