物理化学学报 >> 1987, Vol. 3 >> Issue (01): 35-41.doi: 10.3866/PKU.WHXB19870107

研究论文 上一篇    下一篇

RbIO3·2HI03晶体结构的再修正及其中心对称度

傅正民; 李文秀; 戴金璧; 梁栋材   

  1. 中国科学院物理研究所; 中国科学院生物物理研究所
  • 收稿日期:1985-07-26 修回日期:1986-01-20 发布日期:1987-02-15

REFINEMENT OF THE CRYSTAL STRUCTURE OF RbI03·2HI03 AND ITS CENTROSYMMETRIC DEGREE

Fu Zhengmin; Li Wenxiu; Dai Jinbi; Liang Dongcai   

  1. Institute of Physics; Academia Sinica
    Institute of Biophysics; Academia Sinica
  • Received:1985-07-26 Revised:1986-01-20 Published:1987-02-15

摘要: RbIO_3·2HIO_3的晶体结构用重原子法解得并作了修正。晶体属三斜晶系, 晶胞参数a=0.8332 nm, b=0.8232 nm, c=0.8264 nm; α=60.66°,β=85.80°,γ=66.10°。晶胞中含化学式数z=2. 测量密度D_m =4.61g cm~(-3)。实验和分析结果表明, 结构为非中心对称, 即晶体属P1空间群, 但具有高中心对称度, 作为中心对称度的一种量度<|△r|>w=0.009 nm。⒌玫奖镀敌вΦ挠≈ぁF胍蜃覴=0.076.
每个碘原子同三个最近邻氧原子成共价键, 平均键长约为0.18 nm, 形成一个畸变的10_3~-三角锥; 此外还同三个次近邻氧原子以0.25-0.33 nm的距离结合, 这六个氧原子形成一个畸变的八面体, 碘原予位于其中心。每个铷原子与邻近九个氧原子以0.286-0.351 nm的距离结合, 形成RbO_9多面体。

Abstract: The crystal structure of the compound RbIO_3·2HIO_3 has been redetermined by heavy-atom method and refined by full matrix least-squares method. The crystal belongs to triclinic system with cell dimensions; a=0.8332 nm, b=0.8232 nm, c=0.8264 nm; α=60.66°, β=85.80°, γ=66.10°. Z= 2, D_m = 4.61 g cm~(-3). The structure is non-centrosymmetric; nevertheless, it has a high degree of centrosymmetry, as a measurement of it, < |△r|>w=0.009 nm. The reliable factor is R=0.076.
Three O atoms are bound to each I atom with mean distance of about 0.18 nm forming a distorted IO_3~- triangular cone; in addition other three neighbour O atoms are bound to it with distances of 0.25—0.33 nm. These six O atoms and their centering I atom form a distorted IO_6 octahedron. Nine O atoms are bound to each Rb atom with distances of 0.286—0.351 nm forming a RbO_9 polyhedron.