Phonon spectra of alkali feldspars; phase transitions and solid solutions

Zhang, M.; Wruck, B.; Graeme-Barber, Ann; Salje, E. K. H.; Carpenter, Michael A.

doi:10.2138/am-1996-1-212

Cited by 93 publications

(49 citation statements)

References 27 publications

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“…The vibrational nature of the 156 and 161 cm -1 modes remain unclear, although our polarized measurements (data will be published separately) showed that both modes purely vibrate within the sheet plane, with the former's dipole moment parallel to the a axis and the latter's parallel to the b axis. Based on their frequencies, they could be partially associated with the interlayer cations, because K-O bands commonly occur in this wavenumber region for other silicates (e.g., Zhang et al 1996Zhang et al , 1997. The normal mode calculations by McKeown et al (1999) also suggested the involvement of interlayer cations (K) as well as others (M, T, OH/F).…”

Section: Thermal Behavior Of Lattice Vibrationsmentioning

confidence: 97%

Optical phonons, OH vibrations, and structural modifications of phlogopite at high temperatures: An in-situ infrared spectroscopic study

Zhang

Tarantino

et al. 2016

American Mineralogist

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The thermal behavior of optical phonons and OH vibrations of phlogopite (a trioctahedral mica) was examined at temperatures up to 1000 K using in situ infrared spectroscopy. The results showed that with increasing temperature, O-K bands in phlogopite exhibited a relatively strong variation in frequency in a manner similar to those in muscovite. The work revealed that different types of OH bands (fundamentals and combinations) have very different thermal behavior or temperature dependence, and their absorption coefficients are commonly not constant on heating. OH combination bands that are associated with summation processes of multi-phonon interactions commonly show a decrease in their intensities on heating, but in contrast combination bands due to difference processes generally exhibit an increase. This means that temperature dependencies of their absorption coefficients need to be considered when using the Beer-Lambert law to determine or estimate OH contents or hydrogen concentrations at high temperatures. The results showed a structural anomaly associated with a discontinuity in the temperature derivative of the wavenumber of Al-O and Si-O vibrations and O-H stretching near 600 K. However, framework-related phonon modes in the FIR and MIR regions do not suggest a break of the original monoclinic structural symmetry in the investigated temperature region. The complex changes are attributed to temperature-induced alteration of local configuration involving TO 4 tetrahedra and a possible change of the orientation of OH dipoles, in addition to a previously reported distortion of MO 6 octahedra. Increasing temperature to 1000 K also causes partial dehydroxylation, as evidenced by the disappearance of the OH band near 3623 cm -1 and the decrease in OH band height and area of other OH bands. The study did not record the formation of H 2 O inside phlogopite as a result of partial dehydroxylation. The work offers new data and findings that have important implications in understanding the complex structural modifications and the behavior of phonon modes and the thermal stability of hydroxyls on approaching the dehydroxylation, as well as the way hydrogen is released from micas at high temperatures. Our data also show that phologpite becomes less transparent with increasing temperature suggesting a change of radiative properties and ability to transmit heat, which could be of interest for modeling thermal-transmission in crustal rocks.

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Section: Thermal Behavior Of Lattice Vibrationsmentioning

confidence: 97%

Optical phonons, OH vibrations, and structural modifications of phlogopite at high temperatures: An in-situ infrared spectroscopic study

Zhang

Tarantino

et al. 2016

American Mineralogist

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“…Chemical analyses of samples were performed with the Energy Dispersive Spectroscopy (EDS) technique, using an EDAX Si (Li) detector with an acceleration voltage of 20 kV. The FTIR spectra were acquired in the attenuated total reflectance mode (ATR), between 4000 and 550 cm -1 , using a Perkin Elmer FTIR Spectrum BX with an ATR PIKE MIRacle Specimens for FTIR study were prepared by mixing 1mg of sample in 100 mg of KBr as .suggested by Zhang et al 27 . Spectral analysis was performed over the range 4000-400 cm -1 at a resolution of 4cm -1 .…”

Section: Proportioning and Testingmentioning

confidence: 99%

Compressive strength, microstructure and hydration products of hybrid alkaline cements

et al. 2014

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Ordinary Portland cement (OPC) is the dominant binder in the construction industry with a global production that currently reaches a total of 3 Gt per year. As a consequence, the cement industry's contribution to the total worldwide CO 2 emissions is of about 7% of the total emissions. Publications on the field of alkali-activated binders (also termed geopolymers), state that this new material is, potentially, likely to become an alternative to Portland cement. However, recent LCA studies show that the environmental performance of alkali-activated binders depends, to great extent, of their composition. Also, researchers report that these binders can be produced in a more eco-efficient manner if the use of sodium silicate is avoided. This is due to the fact that the referred component is associated to a high carbon footprint. Besides, most alkali-activated cements suffer from severe efflorescence, a reaction originated by the fact that the alkaline and/or soluble silicates that are added during processing cannot be totally consumed. This paper presents experimental results on hybrid alkaline cements. The compressive strength results and the efflorescence observations show that some of the new mixes already exhibit a promising performance.

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“…It is a particularly relevant technique to investigate a variety of phenomena leading to structural heterogeneity, including the incorporation of molecular impurities (Yi et al 2014), exsolution processes (Zhang et al 1996), stacking variations in layered structures , phase transitions (Salje and Yagil 1996) and cationic ordering (Meyer et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Modeling the attenuated total reflectance infrared (ATR-FTIR) spectrum of apatite

et al. 2016

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Phonon spectra of alkali feldspars; phase transitions and solid solutions

Cited by 93 publications

References 27 publications

Optical phonons, OH vibrations, and structural modifications of phlogopite at high temperatures: An in-situ infrared spectroscopic study

Optical phonons, OH vibrations, and structural modifications of phlogopite at high temperatures: An in-situ infrared spectroscopic study

Compressive strength, microstructure and hydration products of hybrid alkaline cements

Modeling the attenuated total reflectance infrared (ATR-FTIR) spectrum of apatite

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