The incorporation of hydroxyl groups and molecular water in natural zircon (ZrSiO4)

Nasdala, Lutz

doi:10.2475/ajs.301.10.831

Cited by 79 publications

(58 citation statements)

References 33 publications

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“…The bands observed at 3440 cm −1 and 1625 cm − l are assigned to OH − stretching and H O H bending vibrations of structural water. The infrared absorption bands associated with the OH − stretching vibration have earlier been reported [23]. From FTIR spectra the variation in positions of the peaks with sintering temperature of GdFeO 3 nanoparticles also observed.…”

Section: Resultsmentioning

confidence: 76%

Analysis of Ferroelectric, Dielectric and Magnetic Properties of GdFeO₃Nanoparticles

Prakash

Rudramadevi

Buddhudu

2014

Ferroelectrics Letters Section

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In the present work, the chemical co-precipitation method has successfully been employed in the preparation of GdFeO 3 nanoparticles. Prepared samples have been sintered at different temperatures in order to investigate their structural changes using XRD, SEM, and FTIR. P-E hysteresis loops have been measured at various sintering temperatures to understand the grain size effects on ferroelectric properties. From the XRD profile, we have optimized the sintering temperature by comparing this data with JCPDS data. For the temperature optimized sample, we have measured M-H hysteresis loops at 20 K and 300 K to understand its magnetic properties and also dielectric properties, which were measured from room temperatures to 600 • C as function of frequency. The present work has been undertaken to determine their suitability for further development as multifunctional materials.

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Section: Resultsmentioning

confidence: 76%

Analysis of Ferroelectric, Dielectric and Magnetic Properties of GdFeO₃Nanoparticles

Prakash

Rudramadevi

Buddhudu

2014

Ferroelectrics Letters Section

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“…It is unlikely that high amounts of molecular water or hydroxyl are structurally bound in the newly formed crystalline material because: (1) Caruba et al (1985) have found that F is required to stabilize OH in the zircon structure, which was not available in the experimental fluid; (2) first-principle quantummechanical calculations have shown that the non-dissociative adsorption of water on the (100) face of crystalline zircon is strongly preferred with respect to the dissociative adsorption (Balan et al 2001); and (3) the water content in natural crystalline zircon is usually low (Woodhead et al 1991;Nasdala et al 2001). Considering the cracked or porous structure seen in Figure 1p, a possible explanation for the low analytical totals is that some molecular water was retained within pores or microcracks.…”

Section: Hydrothermal Alteration Of Partially Metamict Zirconmentioning

confidence: 97%

Experimental hydrothermal alteration of partially metamict zircon

Geisler

Pidgeon

Kurtz

et al. 2003

American Mineralogist

274

140

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We present the results of a series of hydrothermal experiments on grains from two partially metamict zircon samples from Sri Lanka in the temperature range 350 to 650 ∞C and with different solutions (2 M AlCl 3 , 2 M CaCl 2 , pure H 2 O, and a multi-cation solution). Under these conditions, sharply bounded reaction fronts penetrated into the zircon grains and developed complex lobate and rim structures that resemble structures found in natural zircon systems. The reaction zones are characterized by a marked increase in the cathodoluminescence intensity, a decrease of the back-scattered electron emission, and an increased degree of structural order, as revealed by micro-Raman and infrared spectroscopy. Sensitive high-resolution ion microprobe and electron microprobe measurements revealed that the altered areas gained solvent cations (e.g., Ca 2+ , Ba 2+ , Mg 2+ , Al 3+ ) from the solution and lost variable amounts of Zr, Si, Hf, the REE, U, Th as well as radiogenic Pb. A comparison between "dry" and "hydrothermal" annealing trends shows that the kinetics of structural recovery, including recrystallization of the amorphous phase in metamict zircon, is strongly enhanced under hydrothermal conditions. This finding suggests that water "catalyzes" structural recovery processes in metamict zircon. We found that the structure of the reacted areas does not resemble that of crystalline zircon, i.e., is still characterized by a temperature-dependent degree of disorder, which would not be expected if the reaction is controlled by a coupled dissolution and re-precipitation process. Instead, the alteration process can be described best by a diffusion-reaction-recrystallization model. In this model, it is postulated that the diffusion of water into the metamict structure is the driving force for moving recrystallization fronts. We found that the rate and the extent of solid-state recrystallization of the amorphous phase is an important factor in determining the mobility of trace elements. This interpretation is indicated by the observation that trace elements, including U and Th, were preferentially lost during the reaction with a fluid at low temperatures, where recrystallization of the amorphous material was slow or not activated at all. The observed chemical alteration patterns are believed to reflect a competition between the kinetics of long-range diffusion and ion exchange and the kinetics of the short-range diffusion necessary for the recrystallization process.

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“…Other possible mechanisms for REE substitution include coupling with pentavalent Nb and Ta (mechanism iv, above) or by protonation of O 2-ions of (SiO 4 ) 4-groups. The incorporation of water and hydroxyl into zircon is possible by mechanism (vii) although hydroxyl groups are probably the only hydrous species incorporated into igneous zircon during crystallization (Nasdala et al 2001). Electrostatic neutrality could be maintained by O 2-vacancies, although static O-site vacancies are energetically unfavorable (Crocombette 1999, Williford et al 1999 and are unlikely to persist in the zircon structure.…”

Section: +mentioning

confidence: 99%

The Composition of Zircon and Igneous and Metamorphic Petrogenesis

Hoskin

Schaltegger

2003

Reviews in Mineralogy and Geochemistry

3,633

126

1,680

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The incorporation of hydroxyl groups and molecular water in natural zircon (ZrSiO4)

Cited by 79 publications

References 33 publications

Analysis of Ferroelectric, Dielectric and Magnetic Properties of GdFeO₃Nanoparticles

Analysis of Ferroelectric, Dielectric and Magnetic Properties of GdFeO₃Nanoparticles

Experimental hydrothermal alteration of partially metamict zircon

The Composition of Zircon and Igneous and Metamorphic Petrogenesis

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The incorporation of hydroxyl groups and molecular water in natural zircon (ZrSiO4)

Cited by 79 publications

References 33 publications

Analysis of Ferroelectric, Dielectric and Magnetic Properties of GdFeO3Nanoparticles

Analysis of Ferroelectric, Dielectric and Magnetic Properties of GdFeO3Nanoparticles

Experimental hydrothermal alteration of partially metamict zircon

The Composition of Zircon and Igneous and Metamorphic Petrogenesis

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Analysis of Ferroelectric, Dielectric and Magnetic Properties of GdFeO₃Nanoparticles

Analysis of Ferroelectric, Dielectric and Magnetic Properties of GdFeO₃Nanoparticles