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Lokanath, N.K.; Sridhar, M. A.; Prasad, J. Shashidhara; Gopalakrishna, G. S.; Ashamanjari, K. G.

doi:10.1023/a:1006698320964

Cited by 9 publications

(7 citation statements)

References 9 publications

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“…The P-T conditions were identical in all the experiments. The pH of the resultant products of the experiments was in the range of 3.48-3.60, and hence the products of the present investigations were by and large identical to those reported earlier [12]. The resultant product was washed thoroughly with distilled water using an ultrasonic cleaner.…”

Section: Methodssupporting

confidence: 78%

“…The synthesis of Na 2 CoP 2 O 7 crystals was carried out by a hydrothermal technique at moderate temperature and pressure conditions [11,12]. The experiments were carried out in Morey-type autoclaves provided with Teflon liners at 260 1C and 60-100 bar.…”

Section: Methodsmentioning

confidence: 99%

“…1) exhibited a three-dimensional open-framework tunnel-type cavity structure, similar to the structure of NASICON analogues, which is congenial for hopping of ions. Detailed structural information has been discussed elsewhere [12].…”

Section: Article In Pressmentioning

confidence: 99%

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Hydrothermal synthesis, morphological evolution and characterization of Na2CoP2O7 crystals

Gopalakrishna

Mahesh

Ashamanjari

et al. 2005

Journal of Crystal Growth

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Section: Methodssupporting

confidence: 78%

Section: Methodsmentioning

confidence: 99%

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Hydrothermal synthesis, morphological evolution and characterization of Na2CoP2O7 crystals

Gopalakrishna

Mahesh

Ashamanjari

et al. 2005

Journal of Crystal Growth

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“…13 Whereas the high symmetry phases are very similar in terms of connectivity and ion coordination, the triclinic form is substantially different. The structure presents a 3D open framework described with P1 13,20 or P-1 symmetry. 1g,h.…”

Section: Introductionmentioning

confidence: 99%

Polymorphism in Na₂(Co/Zn)P₂O₇ and Na₂(Co/Fe)P₂O₇ Pyrophosphates: A Combined Diffraction and ³¹P NMR Study

et al. 2021

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Pyrophosphates of the general formula A2BP2O7 (A = alkali metal and B = transition metal) find applications in several technological fields, including rechargeable Na-ion batteries. They present a rich polymorphism vs composition, which may strongly influence their functional properties. Therefore, to selectively obtain a specific structure is crucial for applications. Here, we combine structural investigation techniques (solid-state NMR, X-ray and neutron diffraction, and DFT calculations) to investigate the crystal chemistry of the series Na2(M/M’)P2O7 with couples M/M’ = Co/Zn and Co/Fe. For both the series, a phase transition vs composition is observed. A tetragonal to orthorhombic phase transition is found for the Zn/Co series, and an orthorhombic to triclinic phase transition is found for the Co/Fe series. Such changes are interpreted in view of the different electronic structures of the transition metal ion. In addition, with the support of modeling, short- and long-range structural analysis, we show that the coexistence of two polymorphs for a given composition is possible, suggesting that the final structures may be strongly dependent upon the synthesis procedure.

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“…[1][2][3] Subsequently, there were also reports on pyrophosphates exhibiting simple framework structure with relatively high ionic conductivity values. 4 Recently, there are also reports on hydrated phosphates. 5 Here, we report a new group of hydrated cobaltbearing pyrophosphates, which is paramagnetic in nature at ambient condition.…”

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confidence: 99%

Hydrothermal Synthesis and Structure of Dihydrated Cobalt Pyrophosphates

et al. 2004

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Phosphates were studied extensively owing to their wide range of applications such as piezoelectric, magnetic, luminescence, ceramics and superionics application. [1][2][3] Subsequently, there were also reports on pyrophosphates exhibiting simple framework structure with relatively high ionic conductivity values. 4 Recently, there are also reports on hydrated phosphates. 5 Here, we report a new group of hydrated cobaltbearing pyrophosphates, which is paramagnetic in nature at ambient condition.H2Co2P4O14 crystals were synthesized by hydrothermal processing. The growth of phosphates by the hydrothermal technique is relatively new and is quite complicated for these compounds, because of the highly corrosive and volatile nature of phosphorus at higher temperature.Following earlier methods, the present experiments were carried out in Morey type autoclaves provided with Teflon liners, in the temperature and pressure range of 230 -265˚C and 60 -100 bars. All reagents used in the synthesis process were of Analar grade with 99.9% purity from Merck. The desired quantity of CoCl3 was dissolved in 10 ml of 0.25 M of ETDA solution and the mixture was taken in Teflon liners, then 6 ml of 85% H3PO4 was added. The crystallization was carried out by spontaneous nucleation controlled through a slow and programmed rate of heating. The authors were able to synthesize H2Co2P4O14 crystals under the following experimental conditions: molar ratio, Co2O3 : P2O5 : H2O = 1 -1.5 : 10 -12 : 8 -10; T, 260˚C; P, 80 bars; duration = 8 -10 days.The following reaction could explain the formation of H2Co2P4O14:The crystals obtained by this method were of good quality, exhibiting translucent luster with well developed morphology. The sizes of crystals range from 0.5 to 3 mm with pink color.A single crystal of H2Co2P4O14 of dimensions 0.2 × 0.2 × 0.2 mm was chosen for X-ray diffraction studies. The crystal and experimental data are given in Table 1. The structure was solved by direct methods and refined by full-matrix least squares methods with anisotropic temperature factors for the non-H atoms. H atoms were generated by a difference Fourier map and were placed at a distance of 0.98 Å from the parent atom. The maximum peak lies at the nearest distances of 0.76 Å, 1.58 Å, 1.85 Å and 1.92 Å from the atoms Co1, O3, O11 and O5, respectively. The final coordinates and equivalent thermal parameters of non-H atoms are listed in Table 2. Table 3 gives selected bond distances and bond angles; they agree with their standard values. Figure 1 represents the ORTEP diagram of the molecule with thermal ellipsoids at 50% probability. Crystal structure has an additional feature of a psuedo I-centred lattice translation of (0.5, 0.5, 0.5) for all the atoms except O7, O10, O16 and O19, respectively. But the structure could not be solved and refined in the space group I2/a. The polymerization of phosphate with Co has revealed its coordination and packing mode.Each Co atom has coordination with six pyrophosphate oxygen atoms i.e., from two O-atoms of one terminal pyr...

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Cited by 9 publications

References 9 publications

Hydrothermal synthesis, morphological evolution and characterization of Na2CoP2O7 crystals

Hydrothermal synthesis, morphological evolution and characterization of Na2CoP2O7 crystals

Polymorphism in Na₂(Co/Zn)P₂O₇ and Na₂(Co/Fe)P₂O₇ Pyrophosphates: A Combined Diffraction and ³¹P NMR Study

Hydrothermal Synthesis and Structure of Dihydrated Cobalt Pyrophosphates

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Untitled

Cited by 9 publications

References 9 publications

Hydrothermal synthesis, morphological evolution and characterization of Na2CoP2O7 crystals

Hydrothermal synthesis, morphological evolution and characterization of Na2CoP2O7 crystals

Polymorphism in Na2(Co/Zn)P2O7 and Na2(Co/Fe)P2O7 Pyrophosphates: A Combined Diffraction and 31P NMR Study

Hydrothermal Synthesis and Structure of Dihydrated Cobalt Pyrophosphates

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Polymorphism in Na₂(Co/Zn)P₂O₇ and Na₂(Co/Fe)P₂O₇ Pyrophosphates: A Combined Diffraction and ³¹P NMR Study