Fivefold-coordinated Ti4+ in metamict zirconolite and titanite: A new occurrence shown by Ti K-edge XANES spectroscopy
Fivefold-coordinated Ti4+ in metamict zirconolite and titanite: A new occurrence shown by Ti K-edge XANES spectroscopy
复制标题
变晶锆石和钛矿中的五重配位 Ti4：Ti K 边 XANES 光谱显示的新现象
DOI：
10.2138/am-1997-1-206
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发表时间：
1997
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
摘要采用高分辨分析方法，测定了两个完全变质的锆英石和两个部分变质的钛铁矿中钛的配位环境。Ti K边缘的X射线吸收近边结构（XANES）光谱。五配位Ti是锆英石样品中的主要Ti物种（约占总Ti原子的-80% ± 10%）。这种不寻常的Ti配位在钛铁矿样品中也是可能的。在所研究的任何样品中均未发现[4]Ti的显著证据。与其他非晶材料，如其他变质矿物（aes-chynite和烧绿石）和钛硅酸盐玻璃和熔体的比较表明，五重配位是相当常见的Ti 4+在非周期性结构。然而，变质状态的特征是周围存在不寻常的三角双锥，|5| Ti 4+。
Abstract The coordination environments of Ti in two fully metamict zirconolite samples and two partially metamict titanite samples were determined using high-resolution. X-ray absorption near-edge structure (XANES) spectroscopy at the Ti K edge. Fivefold-coordinated Ti is the dominant Ti species in the zirconolite samples (~-80 ± 10% of the total Ti atoms). This unusual Ti coordination is also possible in the titanite samples. No significant evidence for [4]Ti was found in any of the samples studied. Comparison with other amorphous materials, such as other metamict minerals (aes- chynite and pyrochlore) and titanosilicate glasses and melts, suggests that fivefold coordination is rather common for Ti4+ in aperiodic structures. However, the metamict state is characterized by the presence of unusual trigonal bipyramids around |5|Ti4+.