Coordination of Ti4+in silicate glasses: A high-resolution XANES spectroscopy study at the Ti Kedge
Coordination of Ti4+in silicate glasses: A high-resolution XANES spectroscopy study at the Ti Kedge
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DOI：
10.2138/am-1997-1-205
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发表时间：
1997-02
影响因子：
3.1
通讯作者：
F. Farges
中科院分区：
文献类型：
--
作者：
F. Farges
用高分辨率X射线吸收近边结构(XANES)谱在室温下测定了8种Na2Si4O9-Na2Ti4O9连接(NTS)含钛玻璃和6种ATY2玻璃(A2O·TiO2.2YO2，A=Na、K或Rb，Y=Si或Ge)中的配位环境。在所有研究的玻璃中，五配位的钛([5]Ti)是主要的钛物种(≥占总钛的50±10%)。六配位钛主要存在于钠盐玻璃(NTS、NTS2、NTG2)中，且随TiO2量的增加而增加(在大多数富TiO2NTS玻璃中高达钛总量的40%±10%)，并按Si&Lt；Ge的顺序增加。只在非钠ATY2玻璃中检测到四配位的钛，其含量按Na<；K<；Rb和Ge<；Si的顺序增加。五配位的Ti4+可能以方形锥体、含钛的部分或(|5]Ti=O)O4的形式存在。例如，使用直接方法(X射线吸收和中子散射)合成的氧化物玻璃的Ti4+配位可以帮助解释含钛玻璃的拉曼散射光谱，并更好地估计钛硅酸盐玻璃和熔体的NbO/T比。
Abstract The coordination environment of Ti in eight Ti-bearing glasses of the Na2Si4O9-Na2Ti4O9 join (NTS) and in six ATY2 glasses (A2O·TiO2·2YO2, with A = Na, K, or Rb and Y = Si or Ge) was determined using high-resolution, X-ray absorption near-edge structure (XANES) spectroscopy at the Ti K edge in ambient conditions. Fivefold-coordinated Ti ([5]Ti) is the dominant Ti species (≥50 ± 10% of the total Ti) in all the glasses studied. Sixfold-coordinated Ti was detected mostly in sodic glasses (NTS, NTS2, NTG2), and it increases with TiO2 content (as high as 40 ± 10% of the total of Ti in the most TiO2-rich NTS glasses) and in the order Si < Ge. Fourfold-coordinated Ti was detected only in nonsodic ATY2 glasses, and its content increases in the order Na < K < Rb and Ge < Si. Fivefold-coordinated Ti4+ is probably present as square pyramidal, titanyl-bearing moieties, or (|5]Ti=O)O4. A synthesis of Ti4+ coordination for oxide glasses derived using direct methods (X-ray absorption and neutron scattering) can be used, for instance, to help in the interpretation of Raman scattering spectra collected for Ti-bearing glasses and to estimate NBO/T ratios better for titanosilicate glasses and melts.