Study of the complex vibrational spectra of natural zeolite mordenites

Pechar, F.; Rykl, D.

doi:10.1016/0144-2449(83)90177-x

Cited by 21 publications

(11 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our data for the original hydrated sodium-natrolite (Na-NAThyd) at ambient condition are in good agreement with those reported in the literature (Pechar and Rykl 1983;Line and Kearly 1998). The observed far-IR active modes below 340 cm -1 can be assigned to the translational modes of water molecules and the optical mode of the lattice.…”

Section: Resultssupporting

confidence: 94%

“…Spectroscopic methods such as IR absorption and Raman scattering have been extensively employed to characterize the interactions between the framework and non-framework components in various natural zeolites (Flanigen et al 1974;De Man and van Santen 1992). In the case of mineral natrolite, which has been known to be an exclusively sodium-form in the natrolite group zeolites, Pechar and Rykl (1983) first calculated the framework vibrational modes, while mid-IR vibrational modes were obtained by Gottardi and Galli (1985). Later, studies by Goryainov and coworkers revised the mode assignments based on polarized Raman and IR spectroscopy as well as lattice dynamics calculations (Goryainov et al 2000;Goryainov and Smirnov 2001).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spectroscopic characterization of alkali-metal exchanged natrolites

Liu

Seoung

et al. 2012

American Mineralogist

View full text Add to dashboard Cite

Synchrotron infrared (IR) and micro-Raman spectroscopic studies have been performed on zeolite natrolites as a function of the non-framework composition at ambient conditions. This establishes the spectroscopic characterization of the ion-exchanged natrolites in the alkali-metal series both in the as-prepared hydrated (M-NAT-hyd, M = Li, Na, K, Rb, and Cs) and some stable dehydrated forms (M-NAT-deh, M = Rb and Cs). The former series exhibits non-framework cation-size dependent opening of the helical channels to span ca. 21° range in terms of the chain rotation angle, ψ (or ca. 45° range in terms of the chain bridging angle, T-O2-T). For these hydrated phases, both IR and Raman spectra reveal that the degree of the red-shifts in the frequencies of the helical 8-ring channel as well as the 4-ring unit is proportional to the ionic radius of the non-framework cations. Linear fits to the data show negative slopes of -55.7 from Raman and -18.3 from IR in the 8-ring frequencies and ionic radius relationship. The spectroscopic data are also used to identify the modes of the dehydration-induced "collapse" of the helical 8-ring channels as observed in the stable anhydrous Rb-NAT-deh and Cs-NAT-deh. In addition, we demonstrate that the spectroscopic data in the hydrated series can be used to distinguish different water arrangements along the helical channels based on the frequency shifts in the H-O-H bending band and the changes in the O-H stretching vibration modes.

show abstract

Section: Resultssupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Spectroscopic characterization of alkali-metal exchanged natrolites

Liu

Seoung

et al. 2012

American Mineralogist

View full text Add to dashboard Cite

show abstract

“…Gottardi and Galli (1985) presented powder IR spectra for natrolite, scolecite, and mesolite, but little spectral interpretation was given. Goryainov and Smirnov (2001) reported a better lattice dynamic calculation than that presented by Pechar and Rykl (1983) for natrolite. About 40 additional bands were considered, and they also pointed out some errors in earlier calculations (e.g., Pechar and Rykl 1983).…”

Section: Spectroscopic Investigations Of Nat-topology Zeolitesmentioning

confidence: 83%

“…Goryainov and Smirnov (2001) reported a better lattice dynamic calculation than that presented by Pechar and Rykl (1983) for natrolite. About 40 additional bands were considered, and they also pointed out some errors in earlier calculations (e.g., Pechar and Rykl 1983). Wopenka et al (1998) demonstrated the usefulness of Raman spectroscopy for identification of NAT-type zeolites on the basis of their strikingly different H 2 O O-H stretching bands.…”

Section: Spectroscopic Investigations Of Nat-topology Zeolitesmentioning

confidence: 83%

“…They showed that before the phase transition to the anhydrous phase of natrolite, H 2 O molecules exhibit greater reorientational motion about one of the Ow-HÁÁÁO hydrogen bonds, which involves breaking hydrogen bonds on further heating. Pechar and Rykl (1983) and Pechar (1983) presented powder IR and Raman spectra of natrolite and mesolite and made simple mode assignments based on their lattice dynamic calculations. Gottardi and Galli (1985) presented powder IR spectra for natrolite, scolecite, and mesolite, but little spectral interpretation was given.…”

Section: Spectroscopic Investigations Of Nat-topology Zeolitesmentioning

confidence: 99%

See 1 more Smart Citation

Infrared spectroscopic characterization of dehydration and accompanying phase transition behaviors in NAT-topology zeolites

Wang

Bish

2012

Phys Chem Minerals

View full text Add to dashboard Cite

Relative humidity (P H 2 O , partial pressure of water)-dependent dehydration and accompanying phase transitions in NAT-topology zeolites (natrolite, scolecite, and mesolite) were studied under controlled temperature and known P H 2 O conditions by in situ diffuse-reflectance infrared Fourier transform spectroscopy and parallel X-ray powder diffraction. Dehydration was characterized by the disappearance of internal H 2 O vibrational modes. The loss of H 2 O molecules caused a sequence of structural transitions in which the host framework transformation path was coupled primarily via the thermal motion of guest Na ? /Ca 2? cations and H 2 O molecules. The observation of different interactions of H 2 O molecules and Na ? /Ca 2? cations with host aluminosilicate frameworks under highand low-P H 2 O conditions indicated the development of different local strain fields, arising from cation-H 2 O interactions in NAT-type channels. These strain fields influence the Si-O/Al-O bond strength and tilting angles within and between tetrahedra as the dehydration temperature is approached. The newly observed infrared bands (at 2,139 cm -1 in natrolite, 2,276 cm -1 in scolecite, and 2,176 and 2,259 cm -1 in mesolite) result from strong cation-H 2 O-Al-Si framework interactions in NAT-type channels, and these bands can be used to evaluate the energetic evolution of Na ? /Ca 2? cations before and after phase transitions, especially for scolecite and mesolite. The 2,176 and 2,259 cm -1 absorption bands in mesolite also appear to be related to Na ? /Ca 2? order-disorder that occur when mesolite loses its Ow4 H 2 O molecules.

show abstract

Raman spectroscopic study of CdS, PVA composite films

Badr

El-Kader

Khafagy

2004

J of Applied Polymer Sci

View full text Add to dashboard Cite

ABSTRACT:A new material, which can be used in solar energy utilization, is obtained here by adding different weights of poly(vinyl alcohol) (PVA) to the semiconducting material CdS. The effect of this addition was studied by using FT-Raman spectrometer (based on 1500 mW Nd : YAG laser at 1064 nm), UV-Vis-IR (190 -800 nm) spectrophotometer, and X-ray diffractometer. Our experimental results indicated the appearance of several new Raman bands, which have not existed in both CdS and PVA. Some of the bands which are already existing in the Raman spectra of PVA showed an unexpected systematic increase in their intensities after the addition of CdS to the matrix. On the other hand, some of the new Raman bands appeared in special concentrations of PVA only, whereas some of the Raman bands of CdS were found to disappear after adding PVA. Finally, shifts in some bands associated with random increase in their intensities after adding PVA to CdS was detected in the FT-Raman analysis. The experimental evidence given here might be attributed to the occurrence of new bonds, indicating that the produced mixture is a new material. The assignment of the new bands as well as an interpretation of the obtained variations is given here. Our X-ray diffraction data confirmed the interpretation introduced here. Moreover, the UV-Vis spectra confirmed the existence of new absorption bands in the Visible region. The I-V characteristic curve was measured for a selected concentration of the new composite material, showing a remarkable increase in the values of the conduction current of about two orders of magnitude as compared with the pure PVA material.

show abstract

Study of the complex vibrational spectra of natural zeolite mordenites

Cited by 21 publications

References 2 publications

Spectroscopic characterization of alkali-metal exchanged natrolites

Spectroscopic characterization of alkali-metal exchanged natrolites

Infrared spectroscopic characterization of dehydration and accompanying phase transition behaviors in NAT-topology zeolites

Raman spectroscopic study of CdS, PVA composite films

Contact Info

Product

Resources

About