Si-29 MAS NMR and Raman spectroscopy studies of synthetic microporous (Zr,Hf)-umbite

authors	Lin, Z; Rocha, J
editors	Cejka, J; Zilkova, N; Nachtigall, P
nationality	International
journal	MOLECULAR SIEVES: FROM BASIC RESEARCH TO INDUSTRIAL APPLICATIONS, PTS A AND B
keywords	SILICATES
abstract	Solid Solutions of synthetic analogues of the microporous mixed tetrahedra-octahedra mineral umbite K-2[(Zr1-xHfx)Si3O9](H2O)-H-. (x = 0, 0.17, 0.33, 0.5, 0.67, 0.83 and 1) have been Successfully prepared via hydrothermal synthesis. The materials have been characterised by Si-29 magic-angle spinning (MAS) NMR and Raman spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Si-29 MAS NMR provides clear evidence for the framework substitution of Hf or Zr, which is not forthcoming from other techniques. The hafnium content, x, may be estimated from the intensity of the Si-29 MAS NMR resonances and Raman shifts of bands in the range 880-1000 cm(-1).
publisher	ELSEVIER SCIENCE BV
issn	0167-2991
isbn	0-444-52082-1
year published	2005
volume	158
beginning page	861
ending page	868
web of science category	Chemistry, Physical
subject category	Chemistry
unique article identifier	WOS:000234827500109