Premium
Five‐Coordinate Silicon in Zeolites: Probing SiO 4/2 F − Sites in Nonasil and ZSM‐5 with 29 Si Solid‐State NMR Spectroscopy
Author(s) -
Koller Hubert,
Wölker Axel,
Eckert Hellmut,
Panz Christian,
Behrens Peter
Publication year - 1997
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199728231
Subject(s) - zeolite , silicon , zsm 5 , spectroscopy , nuclear magnetic resonance spectroscopy , hydrothermal circulation , fluoride , fluorine 19 nmr , solid state nuclear magnetic resonance , molecular sieve , ion exchange , chemistry , hydrothermal synthesis , ion , crystallography , materials science , analytical chemistry (journal) , inorganic chemistry , nuclear magnetic resonance , catalysis , stereochemistry , organic chemistry , physics , chemical engineering , adsorption , quantum mechanics , engineering
With fluoride as a mineralizing agent , the high‐silica zeolites nonasil and ZSM‐5 were obtained by hydrothermal syntheses. 29 Si NMR spectroscopy showed that five‐coordinate silicon exists in the form of SiO 4/2 F − in the zeolite frameworks (see the 29 Si{ 19 F} CPMAS NMR spectrum of nonasil on the right). In ZSM‐5 at room temperature the fluoride ion undergoes a dynamic exchange between different silicon atoms, which is frozen out at 140 K.