Synthesis and characterisation of ET(P)S-4 and ET(P)S-10

Phosphorus containing ET(P)S-4 and ET(P)S-10 were synthesized from gels of composition x Na2 O–0.6KF–0.2TiO2 –(1.28 − 4y)x HCl–y P2 O5 –1.49SiO2 –39.5H2 O at 190 °C for 3 days. The XRD patterns are almost identical to the corresponding ETS samples. The presence of phosphorus in the initial gel influences the kinetic parameters of the crystallization process, the morphology and the size of the crystals. The 31 P-NMR of the samples show that part of the phosphorus is attached at the siliceous surface as dihydrogenophosphate SiOPO(OH)2 groups and cannot be introduced in a tetrahedral or octahedral framework position.