Characterization of lanthanum heptamolybdate crystals grown from silica gels

Bhat, Sushma; Kotru, P. N.

doi:10.1016/0254-0584(94)90187-2

Cited by 7 publications

(3 citation statements)

References 6 publications

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“…These cracks do not have specific crystallographic direction and results when the crystals were coated with gold in the vacuum coating plant and examined under scanning electron microscope. Such type of cracking is often associated with crystal having water of crystallization [13, 26, 27]. Figure 1(d) shows an interesting feature on one of the mixed Gd-Ca crystals.…”

Section: Resultsmentioning

confidence: 99%

“…The crystal growth in gels at room temperature pioneered by Henisch and coworkers [6, 7] has been fully exploited in the investigation of growth and characterization of rare earth mixed crystals of Sm-Ba molybdate by Isac and Ittyachen [8]. Studies on the growth of pure lanthanum, neodymium, and mixed La-Nd heptamolybdate single crystals in silica gel have been carried out by Bhat et al [9–13]. Growth, characterization, and thermal behaviour of pure Gd-heptamolybdate, mixed Gd-Ba molybdate, and Gd-Sr molybdate have also been carried out [14–16].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Characterization, and Thermal Kinetics of Mixed Gadolinium: Calcium Heptamolybdate System

Koul

Suri

Singh

et al. 2014

International Scholarly Research Notices

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Synthesis of mixed gadolinium calcium heptamolybdate (GdCaHM) system in silica gel medium using single gel single tube technique has been successfully achieved. The grown crystal exhibits various morphologies, which includes spherulites, multifaceted, and square platelets. The nature of the grown material was established by X-ray diffraction (XRD) studies. Fourier transform infrared spectroscopy (FTIR) study signifies the presence of heptamolybdate (Mo7O24) and water symmetry structure, whereas energy dispersive X-ray analysis (EDAX) establishes the stoichiometric of the grown crystal as GdCaMo7O24·8H2O. The thermal behaviour was studied using the thermoanalytical techniques, which include thermogravimetry (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). Results obtained on the application of TG based models, namely, Horowitz-Metzger, Coats-Redfern, and Piloyan-Novikova, suggest the contracting cylindrical model as the relevant model for the thermal decomposition of the material. The kinetic parameters, namely, the order of reaction (n), activation energy (E a), frequency factor (Z), and entropy (ΔS∗), were also calculated using these three models.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Thermal Kinetics of Mixed Gadolinium: Calcium Heptamolybdate System

Koul

Suri

Singh

et al. 2014

International Scholarly Research Notices

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“…This effect of cracking in crystals is because of the association of water of hydration as has been verified by thermoanalytical techniques discussed in the subsequent section. As such the crystals when examined under the SEM develop cracks due to the vacuum conditions during gold plating and the electron beam heating as has also been reported for other crystals [22][23][24]. Materials with water of hydration pose such problems on being examined using an electron beam [25].…”

Section: External Morphologymentioning

confidence: 95%