MISC - SAKIDA Shinichi

Part 1. Te-125 NMR study of tellurite crystals

S Sakida, S Hayakawa, T Yoko

JOURNAL OF NON-CRYSTALLINE SOLIDS   243 ( 1 )   1 - 12   1999.1

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Language：English   Publisher：ELSEVIER SCIENCE BV  

Te-125 static and magic-angle spinning (MAS) NMR spectra of tellurite crystals with known crystal structures have been measured to determine the isotropic chemical shift delta(iso), the chemical shift anisotropy Delta delta and the asymmetry parameter eta. On the basis of structural unit, tellurite crystals are classified for convenience into TeO3 type (isolated TeO3 and terminal TeO3 type), TeO3+1 type and TeO4 type (alpha-TeO2 and beta-TeO2 type). As a result, the following relations were found: TeO3 greater than or equal to TeO3+1 approximate to beta-TeO2 > alpha-TeO2 in delta(iso(MAS)), beta-TeO2 greater than or equal to alpha-TeO2 > TeO3+1 > terminal TeO3 greater than or equal to isolated TeO3 in \Delta delta\ and TeO4 greater than or equal to TeO3+1 greater than or equal to TeO3 in eta. It was also found that the combination of \Delta delta\ and eta, namely, the relative values of delta(1), delta(2) and delta(3), can elucidate the local structure around Te atoms more definitely than delta(iso). This diagram is useful for examining the structures of tellurite crystals and glasses. (Glasses are discussed in another paper.) (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0022-3093(98)00811-4

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^<125>Te NMR Study of MO-TeO_2(M=Mg, Zn, Sr, Ba and PB)Glasses

SAKIDA Shinichi, HAYAKAWA Satoshi, YOKO Toshinobu

Journal of the Ceramic Society of Japan   107 ( 1245 )   395 - 402   1999

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Language：Japanese   Publisher：The Ceramic Society of Japan  

The structure of MO-TeO_2(M=Mg, Zn, Sr, Ba and Pb)glasses has been studied by means of ^<125>Te static NMR technique. The fraction of TeO_4 trigonal bipyramid(tbp), N_4 decreased and that of TeO_3 trigonal pyramid(tp), N_3 increased almost linearly up to 33.3 mol% MO and rapidly in the range of 33.3 to 40 mol% MO, with increasing MO content. It was found that the glasses containing Mo in the range of 40 to 45 mol% MO consisted only of TeO_3 tp. On the basis of the structural model proposed in a previous paper, the fractions of TeO_4 tbp without a non-bridging oxygen(NBO) atom, TeO_<4/2>(N_4^0> TeO_4 tbp with an NBO atom, O_<3/2> Te-O^-(N_4^-)and TeO_3 tp with two NBO atoms, O_<1/2>Te=(=O)-O^-(N_3^-)were calculated. The structural change for MO-TeO_2 glasses in the range of 0 to 33.3 mol% MO could be well represented by the model previously proposed for alkali tellurite binary glasses. A new model which represents the structural change for MO-TeO_2 glasses containing more than 33.3 mol% MO has been proposed.

DOI： 10.2109/jcersj.107.395

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Other Link： https://jlc.jst.go.jp/DN/JALC/00061068230?from=CiNii

中間酸化物でもガラスになる重金属酸化物ガラス（共著）

崎田真一, 横尾俊信

New Glass   Vol.10 No.4, pp.4-10   1995

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