Author
K. Okuno
Bio: K. Okuno is an academic researcher from Osaka University. The author has contributed to research in topics: Paramagnetism & Néel temperature. The author has an hindex of 1, co-authored 2 publications receiving 56 citations.
Papers
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TL;DR: In this paper, the IR patterns of EuB4O7, Eu2B2O4, and eu2b2O5 were attributed to a three-dimensional network of BO4-tetrahedra, an endless chain of BO3 groups, and a B2O54− ion, respectively.
57 citations
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TL;DR: In this article, the structural features of over 460 anhydrous oxoborates that are described in literature were analysed. And the Lewis acid strengths for all cations other than B 3+ that were found in these structures, using the valences of the cations and their determined average coordination numbers.
Abstract: The structural features of over 460 anhydrous oxoborates that are described in literature were analysed. Lewis acid strengths were calculated for all cations other than B 3+ that were found in these structures, using the valences of the cations and their determined average coordination numbers. From the observation of a restriction of the occurrence of complex polyborate anions to specific ranges of cation Lewis acid strength in existing oxoborate compounds, the Lewis base strengths of the complex polyborate anions (not of the oxygen ligands) were inferred, using the idea that is at the bottom of the valence matching principle, that in the most stable compounds the Lewis acid strength of the cation nearly equals the Lewis base strength of the anion. From this, general inherent rules for the occurrence of the miscellaneous polyborate anions with respect to the ratio cation: boron (A:B), the Lewis acid strength(s) L a of the cation(s) other than B 3+ and the cation radii were developed These rules offer the possibility for a prediction of the stoichiometry and the most probable polyborate structural group that will be adopted by a new anhydrous borate compound.
125 citations
TL;DR: In this article, the luminescence properties of divalent europium complexes with crown ether, azacrown ether, N-pivot-azacrown- ether, and cryptand in methanol or water have been systematically investigated under UV irradiation.
85 citations
TL;DR: In this paper, a new oxoborate β -ZnB 4 O 7 was synthesized under high-pressure/high-temperature conditions from zinc oxide ZnO and boron oxide B 2 O 3 with a walker-type multianvil apparatus at 10.5 GPa and 1100 ǫ c.
60 citations
TL;DR: In this article, modern insights into the synthesis and fundamental optical properties as well as applications of divalent lanthanides as spectral energy converters are discussed, which have especially evolved within the last two decades.
60 citations
TL;DR: In this article, the first crystalline tin borate β-SnB4O7 was synthesized using a Walker-type multianvil apparatus and the single-crystal structure determination showed Pmn21, a = 1086.4(2) pm, b = 444.80(9) pm.
Abstract: In the last years, several investigations were performed in the ternary system Sn−B−O as a simplified variant of the tin-based amorphous composite oxide (TCO), a material in use as negative electrode of lithium-ion rechargeable batteries. All compounds in this system are glasses, so the synthesis of crystalline approximands for a more detailed structural investigation would be favorable. The use of high-pressure/high-temperature conditions (7.5 GPa and 1100 °C; Walker-type multianvil apparatus) led to the synthesis of the first crystalline tin borate β-SnB4O7. The single-crystal structure determination of β-SnB4O7 showed Pmn21, a = 1086.4(2) pm, b = 444.80(9) pm, c = 423.96(8) pm, Z = 2, R1 = 0.0155, and wR2 = 0.0324 (all data). In contrast to the isotypic phases MB4O7 (M = Sr, Pb, Eu, β-Ca, and β-Hg), the position of the tin atom in β-SnB4O7 is influenced by the existence of a stereochemically active lone pair. Furthermore, we report on thermoanalytical aspects (DTA-TG and temperature-resolved in situ po...
53 citations