Neutron diffraction and reverse Monte Carlo modelling of v-B2O3 and 75B2O3–25Na2O glasses

Fábián, Margit; Sváb, E.; Proffen, Thomas; Veress, Erzsébet

doi:10.1016/j.jnoncrysol.2009.12.013

Cited by 16 publications

(16 citation statements)

References 27 publications

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“…Note, that the weight of G Zn‐O ( r ) is significantly higher than that for G Mo‐O ( r ) in the 10MoO 3 –50ZnO–40B 2 O 3 sample (see Table ), therefore it is possible to identify. The peak at 2.4 Å relates mainly to the G O‐O ( r ), which is a characteristic distance for the BO 3 units and overlaps with G B‐B ( r ) . The peak at ~2.8 Å is related to O–O distance characteristic for Mo‐centered oxygen neighborhoods .…”

Section: Resultsmentioning

confidence: 95%

“…The actual peak positions are also shifted. In order to find support for the interpretation, we have displayed the S(Q) data for the v ‐B 2 O 3 and binary 90MoO 3 –10Nd 2 O 3 , as they are the constituent network formers of the investigated ternary system. The basic tendency of the concentration dependence may be related to the characteristic features of the binary glasses, like the presence of the characteristic large peak at 5.8 Å −1 in the S(Q) of v ‐B 2 O 3 or the characteristic peak at 4.9 and 7.3 Å −1 for 90MoO 3 –10Nd 2 O 3 glass.…”

Section: Resultsmentioning

confidence: 96%

“…The peak at ~2.8 Å is related to O–O distance characteristic for Mo‐centered oxygen neighborhoods . For higher r ‐values, the various atomic distributions overlap with each other, the only small peak at 3.6 Å may be related to the B–O second distance in a BO 3 unit type configuration, as it was identified in v ‐B 2 O 3 , which is used as a reference sample to analyze the ternary compositions. All these atomic distance values present valuable new information; furthermore, they serve as input parameters for the starting atomic configuration for the RMC modeling.…”

Section: Resultsmentioning

confidence: 98%

“…Neutron diffraction structure factor, S ( Q ) of ternary zinc boromolybdate samples. The v ‐B 2 O 3 and binary 90MoO 3 –10Nd 2 O 3 glasses are also displayed to help the interpretation of the observed changes: experimental data (marks) and RMC simulation solid line (The curves are shifted vertically for clarity).…”

Section: Resultsmentioning

confidence: 99%

“…The glass formation tendency of MoO 3 –ZnO–B 2 O 3 and of several other similar compositions has been explored and the optical spectroscopic features have been analyzed by Dimitriev et al The structure characterization is challenging, as far as this system contains the conditional network former MoO 3 and the traditional network former B 2 O 3 . For B 2 O 3 ‐based glasses, it is widely accepted that the network consists of BO 3 and BO 4 groups, however, the question often arises concerning the relative amount of the trigonal and tetrahedral units. The basic network former units in MoO 3 ‐based glasses are MoO 4 tetrahedral, however, for systems with high concentration (>80 mol%) both MoO 4 and MoO 6 units are present .…”

Section: Introductionmentioning

confidence: 99%

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Formation of Mixed Bond‐Angle Linkages in Zinc Boromolybdate Glasses

Fábián

Sváb

2016

J. Am. Ceram. Soc.

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The short and medium range structure of glassy MoO3-ZnO-B2O3 has been studied by neutron diffraction and reverse Monte Carlo simulation. The partial atomic pair correlation functions and coordination numbers are presented, not yet reported for this system. We have established that the first neighbor distances do not depend on concentration within limit of error, the actual values are rB-O=1.38 Å, rMo-O=1.72 Å and rZn-O=1.97 Å. It is found that ZnO takes part in the glassy structure as network former, as ZnO4 tetrahedral are linked both to MoO4 and to BO3 and BO4 groups. It is revealed that BO4/BO3 increases with increasing B2O3 content. We have found that only small amount of boroxol ring is present, BO3 and BO4 groups are organized into superstructure units, and a small part is in isolated BO3 triangles. The BO3 and BO4 units are linked to MoO4 or ZnO4 forming mixed [4] Mo-O- [3] B, [4] Mo-O- [4] B, [4] Mo-O- [4] Zn, [3] B-O- [4] Zn, [4] B-O- [4] Zn bond-linkages. IntroductionZinc boromolybdate materials are known as low melting dielectric materials and they have high potential in several applications, due to their stable and unique structure with favourable optical properties [1 and references therein]. The glass formation tendency of MoO3-ZnO-B2O3 and of several other similar compositions has been explored and the optical spectroscopic features have been analyzed by Dimitriev et al. [1][2][3][4][5][6][7][8]. The structure characterization is challenging, as far as this system contains the conditional network former MoO3 and the traditional network former B2O3. For B2O3-based glasses it is widely accepted that the network consists of BO3 and BO4 groups [9][10][11][12][13][14][15][16][17], however, the question often arises concerning the relative amount of the trigonal and tetrahedral units. The basic network former units in MoO3-based glasses are MoO4 tetrahedral, however, for systems with high concentration (> 80 mol %) both MoO4 and MoO6 units are present [3,[18][19][20]. Several studies deal with ZnO containing glassy systems, concerning the role of Zn 2+ cations, which may act as modifier if its fraction is low or network former in case of relatively high content of ZnO [1,[21][22][23][24][25]. The glassy xMoO3-50ZnO-(50-x)B2O3 (x=10, 20, 30 mol %) have been prepared and thoroughly investigated using various optical spectroscopic methods and DTA [1]. Concerning the structural characteristics it was found, that the molybdenum-based glasses contain mainly Mo 6+ ions and a small amount of Mo 5+ ions might be present. It was found, that the coordination state of Mo 6+ ions is mainly (MoO4) 2-tetrahedral units, and formation of diborate, triborate and tetraborate groups, which contain BO3 triangles and BO4 tetrahedra was also suggested. In order get deeper insight into the network structure, including the inter-atomic distances and coordination distributions, we have undertaken neutron diffraction study combined with reverse Monte Carlo (RMC) modeling [26] on the same system. Our interest is mainly foc...

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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