Diluted Fe3+ in silicate glasses: Structural effects of Fe-redox state and matrix composition. An optical absorption and X-band/Q-band EPR study
Diluted Fe3+ in silicate glasses: Structural effects of Fe-redox state and matrix composition. An optical absorption and X-band/Q-band EPR study
复制标题
硅酸盐玻璃中的稀释 Fe3：Fe 氧化还原态和基体组成的结构效应。
DOI：
10.1016/j.jnoncrysol.2015.08.010
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发表时间：
2015
影响因子：
3.5
通讯作者：
G. Calas
中科院分区：
文献类型：
--
作者：
V. Vercamer;Gérald Lelong;H. Hijiya;Y. Kondo;L. Galoisy;G. Calas
采用紫外-可见-近红外吸收光谱和X-和q -波段电子顺磁共振（EPR）研究了标称摩尔成分为16na20 - 10ro - 74sio2 （R = Ca, （Ca,Mg）和Mg）掺杂0.5 wt.% Fe2O3的钠碱性土硅酸盐玻璃，以了解铁氧化还原和玻璃成分对Fe3+光学吸收性能的结构控制。通过与[4]Fe3+、[5]Fe3+和[6]Fe3+晶体进行比较，光学吸收光谱显示除了大部分四面体Fe3+外，还存在5重Fe3+。结合Q波段和x波段的EPR数据显示，Fe3+在孤立的、分布的位点和富铁簇之间的分配，为孤立的Fe3+位点的畸变提供了独特的见解。这也证明了在还原玻璃中存在的残余Fe3+的特殊性质。Ca为Mg增加了四面体Fe3+位的数量，减小了它们的畸变。Mg的存在也减少了孤立的菱形Fe3+位点的数量，促进了团簇的形成。这些团簇证实了硅酸盐玻璃的非均质结构，以及在钠（Ca,Mg）玻璃中Fe3+对钙多于镁的环境的偏好。
Sodium-alkaline earth-silicate glasses, of nominal molar composition 16Na2O–10RO–74SiO2(R = Ca, (Ca,Mg) and Mg) doped with 0.5 wt.% of Fe2O3, were studied by UV–Visible–NIR absorption spectroscopy and electron paramagnetic resonance (EPR) at X- and Q-band to understand the structural control of Fe3+optical absorption properties as a function of iron redox and glass composition. By comparing with a set of[4]Fe3+,[5]Fe3+and[6]Fe3+crystalline references, optical absorption spectra indicate the presence of 5-fold Fe3+in addition to a majority of tetrahedral Fe3+. The combination of Q- and X-band EPR data shows Fe3+partition among isolated, distributed sites and Fe-rich clusters, providing unique insight into the distortion of isolated Fe3+sites. It demonstrates also the peculiar character of the residual Fe3+sites that exist in reduced glasses. Changing Ca to Mg increases the amount of tetrahedral Fe3+sites and decreases their distortion. The presence of Mg also reduces the amount of isolated rhombic Fe3+sites and promotes the formation of clusters. These clusters confirm the non-homogeneous structure of silicate glasses, as well as the preference of Fe3+for a more calcic than magnesian environment in sodic (Ca,Mg) glasses.