Characterization of gel-grown neodymium heptamolybdate crystals

Bhat, Sushma; Kotru, P. N.

doi:10.1007/bf00362154

Cited by 9 publications

(8 citation statements)

References 49 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%

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%

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%

Single crystal growth and characterization of pure and sodium-modified copper tartrate

Quasim

Firdous

Want

et al. 2008

Journal of Crystal Growth

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“…Growth of mixed crystals by gel method was reported by Patel and Arora (1977a, b), Wiktorowska et al (1983), Kotru and Raina (1986) and Jain et al (1996). Growth of neodymiumlanthanum heptamolybdate crystals in silica gels was reported by Bhat et al (1995). Rare earth molybdates, in general, have the potential of wide application in science and technology on account of the fact that they exhibit interesting fluorescent, laser, piezoelectric, ferroelectric and ferroelastic properties.…”

Section: Introductionmentioning

confidence: 95%

Crystallization of mixed rare earth (didymium) molybdates in silica gel

et al. 2001

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Experiments on the growth of mixed rare earth (didymium-a combination of La, Nd, Pr and Sm) molybdates in silica gel medium are reported. The optimum conditions conducive for the growth of these crystals are described and discussed. Concentration programming is reported to enhance the size of crystals by twofold ; the maximum size obtained being about 1 mm 3. EDAX results suggest the crystals to be heptamolybdates of type R 2 Mo 7 O 24 , bearing composition La 1⋅ ⋅23 Nd 0⋅ ⋅43 Pr 0⋅ ⋅29 Sm 0⋅ ⋅05 Mo 7 O 24. The didymium molybdate crystals assume morphologies corresponding to those of spherulites, platelets, cuboids and coalesced crystals. Twinned structure in didymium molybdate crystals are also reported. It is explained that spherulitic morphologies result from aggregates of crystals joining in a spherical envelope. It is suggested that the crystals of didymium molybdates grow by two-dimensional spreading and piling up of layers.

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Characterization of gel-grown neodymium heptamolybdate crystals

Cited by 9 publications

References 49 publications

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

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

Single crystal growth and characterization of pure and sodium-modified copper tartrate

Crystallization of mixed rare earth (didymium) molybdates in silica gel

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