title: Bonding and structure of oxofluoroniobate-based glasses.
abstract: Glasses based on the oxofluoroniobate anion have been characterized by vibrational and solid-state NMR spectroscopy. The mechanism of glass formation in the systems K2NbOF5-MF3 (M = Al, In) has been suggested. A glass network is built from the chains of corner-sharing octahedra through -Nb-F(O)-M- and -Nb-F-Nb- bridges. Isolated NbOF5(2-) octahedra are also present, which is consistent with the glass composition. The high ionic mobility of NbOF5(2-) due to its fast reorientations results in equalization of the Nb-O and Nb-F distances, which is reflected in the appearance of the IR band at 700-800 cm(-1) not observed in the Raman spectrum. Its assignment to bridging -Nb-O-Nb- species accepted in the literature was not proven.
authors: Institute of Chemistry, Far Eastern Branch of Russian Academy of Sciences, 159 Pr. Stoletiya Vladivostoka, 690022 Vladivostok, Russia. laptash@ich.dvo.ru
authors: Natalia M
authors: NM
authors: Laptash
authors: Irina G
authors: IG
authors: Maslennikova
authors: Arseny B
authors: AB
authors: Slobodyuk
authors: Valery Ya
authors: VY
authors: Kavun
authors: Vladimir K
authors: VK
authors: Goncharuk