Preparation and Crystal Structure of New Rare Earth Bismuth Oxynitrates:RBi2O4NO3(R: Y, Sm, Eu, Gd, Tb, Dy, Er, Yb)
Preparation and Crystal Structure of New Rare Earth Bismuth Oxynitrates:RBi2O4NO3(R: Y, Sm, Eu, Gd, Tb, Dy, Er, Yb)
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新型稀土硝酸铋RBi2O4NO3(R: Y, Sm, Eu, Gd, Tb, Dy, Er, Yb)的制备及晶体结构
DOI：
10.1006/jssc.1998.7849
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发表时间：
1998
影响因子：
5.4
通讯作者：
A. Sleight
中科院分区：
文献类型：
--
作者：
N. Kumada;N. Takahashi;N. Kinomura;A. Sleight
以NaBiO3·nH2O和R(NO3)·nH2O为原料，采用低温水热反应合成了新型稀土硝酸铋RBi2O4NO3(R：Y，Sm，Eu，Gd，Tb，Dy，Er，Yb)。晶胞参数与稀土原子的离子半径有关，从R=Yb的a=3.8470(1)和c=10.1762(7)A到R=Sm的a=3.9038(1)和c=10.2370(5)A。用中子粉末衍射数据修正了R=Y的晶体结构，最终的R因子为RWP=4.35，RP=3.29，RI=5.39，RF=4.40%。RBi2O4NO3与R‘xBi3−xO4X(R’：La，Ce，Nd，Eu，Gd；X：CL，Br3，Se)是等结构的，具有基于(RBi2O4)+和(NO3)−层的层状结构。金属原子有三种位置，均由八个氧原子配位，一个由Y原子占据，另两个由铋原子填充。在500℃以上加热时，该化合物分解为(R，Bi)2O_3固溶体，同时伴随着NO和O2的析出。
Abstract New rare earth bismuth oxynitrates, R Bi 2 O 4 NO 3 ( R : Y, Sm, Eu, Gd, Tb, Dy, Er, Yb) were prepared with low temperature hydrothermal reactions using NaBiO 3 · n H 2 O and R (NO 3 )· n H 2 O as starting materials. These rare earth bismuth oxynitrates crystallized in the tetragonal system with space group P 4 mm and Z =1. The lattice parameters depend on the ionic radius of rare earth atoms and range from a =3.8470(1) and c =10.1762(7) A for R =Yb to a =3.9038(1) and c =10.2370(5) A for R =Sm. The crystal structure for R =Y was refined using neutron powder diffraction data, with the final R factors being R WP =4.35, R P =3.29, R I =5.39, and R F =4.40%. R Bi 2 O 4 NO 3 is isostructural with R ′ x Bi 3− x O 4 X ( R ′: La, Ce, Nd, Eu, Gd; X : Cl, Br, Se) having a layered structure based on ( R Bi 2 O 4 ) + and (NO 3 ) − layers. There are three kinds of metal atom positions, all coordinated by eight oxygens; one is occupied by Y atoms and the other two are filled with Bi atoms. On heating above 500°C this compound decomposes to the solid solution ( R ,Bi) 2 O 3 accompanied by the evolution of NO and O 2 .