Structure of V2O5–P2O5 glasses by X-ray and neutron diffraction

Hoppe, Uwe; Wyckoff, N.P.; Schmitt, Melodie L.; Brow, Richard K.; Schöps, A.; Hannon, Alex C.

doi:10.1016/j.jnoncrysol.2011.09.038

Cited by 26 publications

(28 citation statements)

References 39 publications

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“…Additionally, the assignments shown in Fig. 4 are supported by the comparison of the distances determined by us and the values of interatomic distances in vanadium oxides like V 2 O 5 and vanadate based glasses known from the literature [6,13,14]. The position of the strongest peak at 1.79 Ǻ (Fig.…”

Section: Structural Propertiessupporting

confidence: 76%

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Properties of 15Ag2O∙70V2O5∙15P2O5 glass prepared by melt quenching, twin rollers and mechanosynthesis method

et al. 2015

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Section: Structural Propertiessupporting

confidence: 76%

“…Because of high contents of V 2 O 5 in our glass, we adopted that VO 5 pyramid is a basic glass network unit. In the light of the recent structure research by Hoppe et al [6], it seems that VO 5 polyhedra in our highly-connective glasses are mainly corner-shared.…”

Section: Structural Propertiesmentioning

confidence: 49%

Properties of 15Ag2O∙70V2O5∙15P2O5 glass prepared by melt quenching, twin rollers and mechanosynthesis method

et al. 2015

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“…The measured Na-O coordination number of 3.77 is smaller than the value of 5.0 for crystalline -NaPO 3 [90], but the crystal has a longer average bond length, 2.43 Å, compared to the average for the glass, 2.36 Å, and so the crystal should be expected to have a larger coordination number. In a neutron diffraction study of sodium metaphosphate glass, Pickup et al [37] found a Na-O coordination number of 4.0 at a single distance of 2.33 Å, whilst in a combined neutron and X-ray diffraction study Hoppe et al [91] found an asymmetric distribution of Na-O distances with a total coordination number of 4.20.…”

Section: Modifier Coordination In Binary Metaphosphatesmentioning

confidence: 99%

Structural and physico-chemical analysis of calcium/strontium substituted, near-invert phosphate based glasses for biomedical applications

Patel¹,

Moss²,

Hossain³

et al. 2017

Acta Biomaterialia

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Neutron diffraction, 23 Na and 31 P NMR and FTIR spectroscopy have been used to investigate the structural effects of substituting CaO with SrO in a 40P 2 O 5 ·(16-x)CaO·20Na 2 O·24MgO·xSrO glass, where x is 0, 4, 8, 12 and 16 mol%. The 31 P solid-state NMR results showed similar amounts of Q 1 and Q 2 units for all of the multicomponent glasses investigated, showing that the substitution of Sr for Ca has no effect on the phosphate network. The M-O coordinations (M= Mg, Ca, Sr, Na) were determined for binary alkali and alkaline earth metaphosphates using neutron diffraction and broad asymmetric distributions of bond length were observed, with coordination numbers that were smaller and bond lengths that were shorter than in corresponding crystals. The Mg-O coordination number was determined most reliably as 5.0(2). The neutron diffraction results for the multicomponent glasses are consistent with a structural model in which the coordination of Ca, Sr and Na is the same as in the binary metaphosphate glass, whereas there is a definite shift of Mg-O bonds to longer distance. There is also a small but consistent increase in the Mg-O coordination number and the width of the distribution of Mg-O bond lengths, as Sr substitutes for Ca. Functional properties, including glass transition temperatures, thermal processing windows, dissolution rates and ion release profiles were also investigated. Dissolution studies showed a decrease in dissolution rate with initial addition of 4 mol% SrO, but further addition of SrO showed little change. The ion release profiles followed a similar trend to the dissolution rates observed. The limited changes in structure and dissolution rates observed for substitution of Ca with Sr in these fixed 40 mol% P 2 O 5 glasses were attributed to their similarities in terms of ionic size and charge.

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“…. X-ray and neutron diffraction measurements conclude that V-O structural units undergo complex changes as the amount of V 2 O 5 content decreases 25 . According to an analysis, short-range structural units change from a VO 4+1 trigonal pyramid for x = 0, VO 4+1 trigonal bipyramid and VO 5+1 square pyramid for x = 27 and VO 5+1 square pyramid for x = 27-50 to a VO 5+1 square pyramid of β-VOPO 4 and VO 6 distorted octahedron of (VO) 2 P 2 O 7 for x = 50.…”

mentioning

confidence: 99%

“…To design compatible properties for various applications, understanding the glass structure is crucial. Structures of V 2 O 5 glass and (100-x)V 2 O 5 -xP 2 O 5 (VPx) glasses have been widely studied by using spectrometry techniques 22,23 and diffraction techniques [24][25][26] . The results for VPx glasses obtained by using a Fourier transform infrared spectrometer (FT-IR) indicate a structural change from V 2 O 5 -to β-VOPO 4 -like structures around x = ~25 22 .…”

mentioning

confidence: 99%

Controlling oxygen coordination and valence of network forming cations

Aoyagi

Kohara

Naito

et al. 2020

Sci Rep

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Understanding the structure-property relationship of glass material is still challenging due to a lack of periodicity in disordered materials. Here, we report the properties and atomic structure of vanadium phosphate glasses characterized by reverse Monte Carlo modelling based on neutron/synchrotron X-ray diffraction and EXAFS data, supplemented by Raman and NMR spectroscopy. In vanadium-rich glass, the water durability, thermal stability and hardness improve as the amount of P 2 o 5 increases, and the network former of the glass changes from VO x polyhedra to the interplay between VO x polyhedra and po 4 tetrahedra. We find for the first time that the coordination number of oxygen atoms around a V 4+ is four, which is an unusually small coordination number, and plays an important role for water durability, thermal stability and hardness. Furthermore, we show that the similarity between glass and crystal beyond the nearest neighbour distance is important for glass properties. These results demonstrate that controlling the oxygen coordination and valence of the network-forming cation is necessary for designing the properties of glass. Oxide glass components are basically classified into network formers, network modifiers and intermediates by Zachariasen 1 and Sun 2. Typical network formers satisfy Zachariasen's rules 1 , but V 2 O 5 is classified as a network former 1 or intermediate 3. This is because it is hard for this oxide to form glass on its own because the oxygen coordination number is five in a crystalline phase, which is larger than the coordination number of typical network formers of three and four. V 2 O 5 based glasses have been widely studied for decades because V 2 O 5 glass is a typical semiconducting glass originating from hopping conduction. Indeed, not only fundamental research on electrical properties 4-8 but also applied research on cathode materials for lithium, sodium and magnesium ion batteries have been reported 9-12. This glass also has a low glass transition temperature and relatively low thermal expansion 4. These are quite attractive properties for low-melting glass used for sealing. In this field, lead borate glass with a high percentage of PbO has been applied to sealing below 400 °C in electronic devices, such as IC ceramic packages, crystal oscillators and micro-electro-mechanical systems. Since lead components are a hazardous substance for human health and the environment, it is necessary to avoid the use of PbO, and hence, V 2 O 5 based glass is a promising material for overcoming this problem 13-19. However, there are two critical problems that face the practical application of V 2 O 5 based glass: poor water durability and low thermal stability.

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Structure of V2O5–P2O5 glasses by X-ray and neutron diffraction

Cited by 26 publications

References 39 publications

Properties of 15Ag2O∙70V2O5∙15P2O5 glass prepared by melt quenching, twin rollers and mechanosynthesis method

Properties of 15Ag2O∙70V2O5∙15P2O5 glass prepared by melt quenching, twin rollers and mechanosynthesis method

Structural and physico-chemical analysis of calcium/strontium substituted, near-invert phosphate based glasses for biomedical applications

Controlling oxygen coordination and valence of network forming cations

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