Structure refinement of bismuth oxide bromide, BiOBr
Structure refinement of bismuth oxide bromide, BiOBr
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DOI：
10.1107/s0108270186093307
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发表时间：
1986-08
期刊：
影响因子：
--
通讯作者：
J. Ketterer;V. Krämer
中科院分区：
文献类型：
--
作者：
J. Ketterer;V. Krämer
分子量为304.88，四面体，P_4/nmm，a= 3.9233（5），c= 8.105（2）A，V= 124.7（3）/k_3，Z= 2，D_1 = 8.082，Dx= 8.12 g cm-3，2（Mo Ks）= 0.71069 A，#= 825.5 cm-1，F（000）= 248，室温;最终R= 0.048，190个独立观察反射。该化合物属于BiOC 1（PbFC 1）层状结构家族;其结构在系统研究铋氧化物卤化物的晶体化学和键关系的过程中得到细化。Bi-O和Bi-Br键长分别为2.3251（3）和3.1698（3）。尺寸为2 × 2 × 0.5mm，通过在983 - 943 K下将商业BiOBr粉末在真空石英坩埚中升华5天来制备。选择尺寸为200 x 10 x 5 lam的单晶; Dm值来自班尼斯特和Hey（1935）。Enraf-Nonius CAD-4衍射仪，石墨-单色化Mo Ka辐射，扫描宽度1.2%ctr--20扫描模式，20< 70，h：-6至6，k：0至6，h 0至13;用GUINIER程序计算点阵参数（Carpentier，1973年），使用立方As 2 O3校正了Guinier粉末数据（α = 11.0765 A）作为内标，并用程序LSUCRE（Evans，Appleman & Handwerker，1963）精制。SHELX 76（Sheldrick，1976）系统;两个标准反射：无显著变化; 635个全反射，199个独立反射，190个1> 3 o（/）; Ri，t= 0.071（F）;洛伦兹偏振、吸收（透射因子0.05 ~ 0.66）和消光[g= 0.6（1）× 10-2]效应的修正。作为原子参数的起始组，选择了从粉末数据中获得的班尼斯特和海伊（1935）的值。位置和各向异性热参数的细化导致最终R= 0.048，t wR= 0.045/w= 1/[a2（F）+ 10- 4F 2]}，基于F的最小二乘法; 11个参数细化;最大值。A/o< 10-4; max. Ap= 5.5，最小值Ap=-4.7 e Aa接近重原子;使用并校正中性原子的散射因子（Cromer & Mann，1968）
Abstract Mr= 304.88, tetragonal, P4/nmm, a= 3.9233 (5), c= 8.105 (2) A, V= 124.7 (3)/k3, Z= 2, D,,= 8.082, Dx= 8.12 g cm-3, 2 (Mo Ks)= 0.71069 A,#= 825.5 cm-l, F (000)= 248, room temperature; final R= 0.048 for 190 independent observed reflections. The compound belongs to the BiOC1 (PbFC1) layer structure family; its structure was refined in the course of a systematic study on crystal chemistry and bond relationships of the bismuth oxide halides. The Bi--O and Bi--Br bond lengths are 2.3251 (3) and 3.1698 (3) A, respectively.Transparent yellowish platelets of max. dimensions 2 x 2 x 0.5 mm were prepared by sublimation of commercial BiOBr powder in an evacuated quartz ampoule for 5 d from 983 to 943 K. A single crystal of size 200 x 10 x 5 lam was selected; value of Dm from Bannister & Hey (1935). Enraf-Nonius CAD-4 diffractometer, graphite-mono-chromatized Mo Ka radiation, scan width 1.2% ctr--20 scan mode, 20< 70, h:-6 to 6, k: 0 to 6, h 0 to 13; lattice parameters with program GUINIER (Carpentier, 1973), which corrected Guinier powder data using cubic As203 (a= 11.0765 A) as internal standard, and refined with program LSUCRE (Evans, Appleman & Handwerker, 1963). SHELX76 (Sheldrick, 1976) system; two standard reflec-tions: no significant variation; 635 total reflections, 199 independent, 190 with 1> 3o (/); Ri, t= 0.071 (on F); corrections for Lorentz-polarization, absorption (transmis-sion factors 0.05 to 0.66), and extinction [g= 0.6 (1) x 10-2] effects. As starting set of atom parameters the values of Bannister & Hey (1935), obtained from powder data, were chosen. Refinement of positional and anisotropic thermal parameters resulted in final R= 0.048, t wR= 0.045/w= 1/[a2 (F)+ 10-4F2]}, least squares based on F; 11 parameters refined; max. A/o< 10-4; max. Ap= 5.5, min. Ap=-4.7 e Aa close to heavy atoms; scattering factors of neutral atoms (Cromer & Mann, 1968) used and corrected