Ammonium-iodide route to anhydrous EuI2： mechanism and preparation

Anhydrous EuI2 is an essential raw material for novel Eu^2＋-doped halide scintillators such as SrI2：Eu, CsBa2I5：Eu and BaBrI ：Eu. An efficient and economic method to produce high purity anhydrous EuI2 is critical for future development and applications of these scintillators. In this paper, the ammo...

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Published inJournal of rare earths Vol. 33; no. 11; pp. 1189 - 1195
Main Author 刁成鹏 余金秋 李红卫 彭鹏 吴浩 何华强 颜世宏 胡运生
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.11.2015
Subjects
ammonium iodide route
anhydrous EuI2
rare earths
scintillator
X射线衍射
制备
无水
水合物
水解机理
热分解过程
碘化铵
路线图
anhydrous EuI2
scintillator
ammonium iodide route
rare earths
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ISSN1002-0721
2509-4963
DOI10.1016/S1002-0721(14)60545-7

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Summary:Anhydrous EuI2 is an essential raw material for novel Eu^2＋-doped halide scintillators such as SrI2：Eu, CsBa2I5：Eu and BaBrI ：Eu. An efficient and economic method to produce high purity anhydrous EuI2 is critical for future development and applications of these scintillators. In this paper, the ammonium-iodide route to anhydrous EuI2 was investigated, and anhydrous EuI2 with purity of 99.95 wt.% was successfully prepared. The dehydration mechanisms of europium iodide hydrate and its mixture with NH4I were comparatively investigated by X-ray diffraction（XRD）, thermal analysis and fluorescence spectroscopy. The thermal decomposition process of individual europium iodide hydrate was revealed as follows： EuI3·9H2O→EuI 3·8H2O→EuI 3·7H2O→EuI 2·H2O→EuI2, and the hydrolysis mechanism of europium hydrate was comprehensively studied. When europium iodide hydrate was dehydrated with NH4I, NH4Eu2I5 formed as an intermediate product, and the hydrolysis of EuI2 was effectively restrained. The role of NH4I as an iodination agent was also discussed.
Bibliography:11-2788/TF
Anhydrous EuI2 is an essential raw material for novel Eu^2＋-doped halide scintillators such as SrI2：Eu, CsBa2I5：Eu and BaBrI ：Eu. An efficient and economic method to produce high purity anhydrous EuI2 is critical for future development and applications of these scintillators. In this paper, the ammonium-iodide route to anhydrous EuI2 was investigated, and anhydrous EuI2 with purity of 99.95 wt.% was successfully prepared. The dehydration mechanisms of europium iodide hydrate and its mixture with NH4I were comparatively investigated by X-ray diffraction（XRD）, thermal analysis and fluorescence spectroscopy. The thermal decomposition process of individual europium iodide hydrate was revealed as follows： EuI3·9H2O→EuI 3·8H2O→EuI 3·7H2O→EuI 2·H2O→EuI2, and the hydrolysis mechanism of europium hydrate was comprehensively studied. When europium iodide hydrate was dehydrated with NH4I, NH4Eu2I5 formed as an intermediate product, and the hydrolysis of EuI2 was effectively restrained. The role of NH4I as an iodination agent was also discussed.
anhydrous EuI2 ammonium iodide route scintillator rare earths
ISSN:1002-0721
2509-4963
DOI:10.1016/S1002-0721(14)60545-7