Evidence for symmetric cationic sites in zirconium-bearing oxide glasses

Abstract

The local environment of Zr in a borosilicate glass has been investigated by combining molecular dynamics (MD) simulations with Zr K-edge x-ray absorption spectroscopy (XAS) measurements. Two- and three-body distribution functions in agreement with the experimental data were obtained. The oxygen first neighbors around Zr are found to be narrowly distributed, revealing almost perfectly regular ZrO6 octahedra. Significant three-body contributions (Zr-O-O) to the XAS signal are observed, probing the existence of highly symmetric cationic sites in a glassy network. The gZrO(r) first peak derived from the experimental data is narrower than the one given by the MD model, thus providing elements for further improvements of the MD potentials

Structural role of ZrO2 and its impact on properties of boroaluminosilicate nuclear waste glasses

“…This slightly distorted [ZrO 6 ] octahedral are consistent with experimental observations. [44][45][46] BAD of O-Na-O shows a higher/sharper peak at~60°and a lower/broader peak at 110°for all compositions, which is consistent with a previous study on soda-lime silicate glasses. 53 Interestingly, BADs of O-Ca-O exhibit higher intensity of the peak~60°as compared to the peak~90°.…”

Structure study of multi-component borosilicate glasses from high-Q neutron diffraction measurement and RMC modeling

“…6) in a fairly good agreement with Refs. [12][13][14][15], even though the sharp peak in our results is more pronounced with a significantly Table 5. Fig.…”

“…Addition of Zr has also been found very promising for stabilizing the glass, due to its strong charge compensating ability [11]. However, it is still a question of debate whether it acts as a network former or as a modifier [12][13][14][15].…”

Mineral-Aqueous Solution Interfaces and Their Impact on the Environment

“…, and IV Zn improve chemical durability (Le Grand et al, 2000;Weigel et al, 2008) . Similarly, highly charged cations such as Zr 4+ occur in regular octahedral sites and play a networking role Galoisy et al, 1999;Ferlat et al, 2006) . Pauling's rules imply local charge compensation of these sites by alkalis/alkaline earths and explain the structural stability of this local structure .…”