Structural temperature dependence in α‐lithium iodate: Neutron and x‐ray study between 20 and 500 K
Structural temperature dependence in α‐lithium iodate: Neutron and x‐ray study between 20 and 500 K
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α-碘酸锂的结构温度依赖性：20 至 500 K 之间的中子和 X 射线研究
DOI：
10.1063/1.444725
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发表时间：
1983
影响因子：
4.4
通讯作者：
S. Abrahams
中科院分区：
文献类型：
--
作者：
C. Svensson;J. Albertsson;R. Liminga;A. Kvick;S. Abrahams
六方 α-LiIO3 的晶体结构已通过中子和 X 射线衍射在 20 至 500 K 的十个温度下确定。在布鲁克海文高通量束流反应堆中在 20、100、200 和 295 K 下测量了 4 组（每组 1248 至 1622 次反射）λ=1.0467 A 的中子数据。在 CAD-4 X 射线衍射仪上使用 MoKα 辐射测量了另外 13 个数据集（每组 1706 至 2963 个反射）。每个温度下的结构均通过空间群 P63 中的最小二乘法进行细化。最终的一致因子在 0.023 到 0.050 之间下降。 295 K 时的晶胞尺寸为 a=5.481 27(6)、c=5.171 65(4) A，具有非线性热膨胀。结构随温度的主要变化在于 Li 和 O 相对于 I 的原子位置：这些位置由 O(z)T=−0.8435(3) A+62(4)×10−9 T2 A K−2 和 Li(z)T=0.3808(10) A+167 (18)×10−9 T2 A K−2 给出。碘酸根离子的 I-O 键长恒定为 1.8081(4) A，但 O-I-O 角从 99.97(2)° 增加......
The crystal structure of hexagonal α‐LiIO3 has been determined by neutron and x‐ray diffraction at ten temperatures from 20 to 500 K. Four sets (1248 to 1622 reflections per set) of neutron data at λ=1.0467 A were measured at the Brookhaven High Flux Beam Reactor at 20, 100, 200, and 295 K. The integrated intensities of a further 13 data sets (1706 to 2963 reflections per set) were measured using MoKα radiation on a CAD‐4 x‐ray diffractometer. The structure at each temperature was refined by least squares in space group P63. The final agreement factors fell between 0.023 and 0.050. The unit cell dimensions at 295 K are a=5.481 27(6), c=5.171 65(4) A, with nonlinear thermal expansions. The principal change in structure with temperature is in the atomic positions of Li and O relative to I: The positions are given by O(z)T=−0.8435(3) A+62(4)×10−9 T2 A K−2 and Li(z)T=0.3808(10) A+167 (18)×10−9 T2 A K−2. The iodate ion has a constant I–O bond length of 1.8081(4) A, but the O–I–O angle increases from 99.97(2)° ...