CC BY 3.0 DESekiya, TakaoMochida, NorioOhtsuka, AtsushiSoejima, AyakoYasumori, AtsuoYamane, Masayuki2024-08-272024-08-271993https://oa.tib.eu/renate/handle/123456789/14967https://doi.org/10.34657/1398911B Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectra of BO3/2-TeO2 glasses have been used to determine the compositional dependence of the fraction of 4-coordinated boron atoms, N4 = BO4/(BO3+BO4). In 1 BO3/2 ∙ 99 TeO2 (mol%) glass, almost all boron atoms form BO4 tetrahedra. The fraction N4 decreases with increase of BO3/2 content. The authors propose a glass structural model in which the TeO3 trigonal pyramids formed by a part of the tellurium atoms are connected with the BO4 tetrahedra by vertex-sharing. An excess and a deficiency of local charges of a TeO3 trigonal pyramid and a BO4 tetrahedron compensate each other. The conversion of a BO3 triangle to a BO4 tetrahedron is concurrent with the formation of a TeO3 trigonal pyramid.enghttps://creativecommons.org/licenses/by/3.0/de/660Article