| Studies on NaLn(WO_4)_2 Single Crystals(Ln=La,Pr,Nd) |
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| 作者姓名： | 李红军 洪广言 越淑英 |
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| 作者单位： | Changchun Institute of Applied Chemistry Academia Sinica，Changchun 130022，China，Changchun Institute of Applied Chemistry，Academia Sinica，Changchun 130022，China，Changchun Institute of Applied Chemistry，Academia Sinica，Changchun 130022，China |
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| 摘 要： | The crystals of NaLn(WO4)_2(Ln=La,Pr,Nd)are grown from a melt of LiCl-Na_2WO_4 flux by slowcooling method.The chemical analysis data show that the crystals are NaLa(WO_4)_2,NaPr(WO4)_2 andNaNd(WO_4)_2 respectively.The structures of the crystals are ascertained that they belong to scheelite structureof the tetragonal system with a space group of 14_1/a.The lattice parameters of the crystals have beencalculated.It is found that the cell volume of NaLn(WO_4)_2 crystals decrease with a decrease of Ln~(3 )radius.The bond distances and their angles in NaLa(WO_4)_2 and NaNd(WO_4)_2 are given.It is found that inaccordance with the decrease of ionic radii of Ln~(3 )due to increase of atomic number,the bond distances betweenLn-O,Ln-Ln and W-O decrease regularly.The infrared spectra of NaLn(WO_4)_2 are measured.Thetetrahedra characteristic absorptions of WO_4~(2-)are shown.The sensitization of host lattice is observed from theexcitation and fluorescent spectra of NaLa(WO_4)_2 and NaPr(WO_4)_2.
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Studies on NaLn(WO_4)_2 Single Crystals(Ln=La,Pr,Nd) |
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| Li Hong-Jun Hong Guang-Yan Yue Shu-Ying.Studies on NaLn(WO_4)_2 Single Crystals(Ln=La,Pr,Nd)[J].Journal of Rare Earths,1991(1). |
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| Authors: | Li Hong-Jun Hong Guang-Yan Yue Shu-Ying |
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| Abstract: | The crystals of NaLn(WO4)_2(Ln=La,Pr,Nd)are grown from a melt of LiCl-Na_2WO_4 flux by slow cooling method.The chemical analysis data show that the crystals are NaLa(WO_4)_2,NaPr(WO4)_2 and NaNd(WO_4)_2 respectively.The structures of the crystals are ascertained that they belong to scheelite structure of the tetragonal system with a space group of 14_1/a.The lattice parameters of the crystals have been calculated.It is found that the cell volume of NaLn(WO_4)_2 crystals decrease with a decrease of Ln~(3 )radius. The bond distances and their angles in NaLa(WO_4)_2 and NaNd(WO_4)_2 are given.It is found that in accordance with the decrease of ionic radii of Ln~(3 )due to increase of atomic number,the bond distances between Ln-O,Ln-Ln and W-O decrease regularly.The infrared spectra of NaLn(WO_4)_2 are measured.The tetrahedra characteristic absorptions of WO_4~(2-)are shown.The sensitization of host lattice is observed from the excitation and fluorescent spectra of NaLa(WO_4)_2 and NaPr(WO_4)_2. |
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| Keywords: | Rare earth Crystal growth Tungstates Structure Excitation and fluorescence spectra |
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