REINVESTIGATION OF TITANIUM SILICALITE BY X-RAY-ABSORPTION SPECTROSCOPY - ARE THE NOVEL TITANIUM SITES REAL

EXAFS studies have been carried out on titanium silicalite-1 (TS-1). T he titanium atom is coordinated to four oxygen atoms at the distance o f 1.80(1) angstrom. There is no evidence for the presence of 5- and 6- coordinated titanium species or the novel 4-coordinated titanium speci es involving [TiO(x)] units sharing edges with [SiO4] units. The EXAFS spectrum of TS-1 appears to be consistent with the model that titaniu m resides at the tetrahedral sites of the framework.