Zinc environment in aluminoborosilicate glasses by Zn K-edge extended x-ray absorption fine structure spectroscopy

Abstract

The structural surrounding of Zn in inactive nuclear glasses was determined using extended x-ray absorption fine structure spectroscopy. Zn was found in tetrahedralcoordination ([4]Zn) with [4]Zn–O distances of 1.95 Å. ZnO4 tetrahedra shared corners with SiO4 tetrahedra [d(Zn–Si) around 3.20 Å]. The oxygens of the Zn–O–Si bonds were charge compensated by Na+ and, to a minor extent, by Cs+. The influence of [4]Zn on the formation of charge-compensating cations at the expense of network modifiers may explain the stabilizing effect of Zn in these glasses.

Structural evolution of glass surface during alteration: Application to nuclear waste glasses

“…The surrounding of several components in SON 68 such as Zr, Zn, Mo or Pd has been already discussed [15][16][17][18]. During the first stages of glass alteration at 90°C, X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM) confirm that the morphology and chemical composition of glass surface is more modified during alteration in deionized water than under near-saturation conditions.…”

A combined experimental and computational approach to (Na2O)1−x·CaO·(ZnO)x·2SiO2 glasses characterization

“…Recent results obtained by means of X-ray absorption spectroscopy studies on multi-component glasses [2,3] explain the observed structure-reinforcing effect by invoking a network-forming role for the tetrahedral Zn in these glasses. These findings were confirmed/corroborated by a recently reported experimental and computational study on the quaternary glass system Na 2 O AE CaO AE 2SiO 2 AE xZnO, (where x varied in the range 0.00-0.68; x = 0.68 is the maximum of ZnO addition which still had enabled to obtain a glass) [4].…”

Zinc-containing bioactive glasses for bone regeneration, dental and orthopedic applications

“…Also, the electrostatic attraction of the excess of negative charge in the (ZnO 4 ) 2− tetrahedral should restrain further the mobility of Na + ions [41]. In general, zinc has been shown to exhibit a marked preference for square planar complexes in simple alkali silicate glasses [43] and therefore, in most cases of zinc-containing 45S5 BG, Zn 2+ can be a fourcoordinated weak network former [80]. Kapoor et al [44] studied the effect of zinc on the structure of melt-quenched alkali-free CaO-MgO-SiO 2 -P 2 O 5 -CaF 2 based glass system.…”