The structure of liquid alkali nitrates and nitrites.
The structure of liquid alkali nitrates and nitrites.
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液体碱金属硝酸盐和亚硝酸盐的结构。
DOI：
10.1039/c7cp03465b
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
J. B. Parise
中科院分区：
文献类型：
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作者：
M. Wilding;M. Wilson;Mauro C. C. Ribeiro;C. Benmore;J. Weber;O. Alderman;A. Tamalonis;J. B. Parise
高能 X 射线衍射与无容器技术相结合，确定了一系列碱、硝酸铵和亚硝酸盐液体的结构。该系统已使用分子动力学模拟进行建模，允许分子阴离子的灵活性和电荷的移动。该模型再现了实验确定的低 Q 值和高 Q 值范围内的散射函数，反映了分子间和分子内的长度尺度。对于硝酸铵，衍射数据的最佳拟合是通过假设 NH4+ 阳离子的半径更接近 Cs+ 的半径来获得的，而不是像之前通常假设的更小的阳离子（例如 Rb+）。碱金属亚硝酸盐显示出由于氮-氮空间相关性而出现的长度尺度，这取决于温度和碱金属阳离子的特性。相应的硝酸盐在氮-氮相关性中显示出更微妙的影响。因此，对于相应的亚硝酸盐和硝酸盐来说，N-N 长度尺度的性质似乎有所不同。
High energy X-ray diffraction has been combined with containerless techniques to determine the structure of a series of alkali and ammonium nitrate and nitrite liquids. The systems have been modelled using molecular dynamics simulation which allows for the flexibility of, and movement of charge within, the molecular anions. The model reproduces the experimentally-determined scattering functions in both the low- and high-Q regimes reflecting the inter- and intra-molecular length-scales. For ammonium nitrate the best fit to the diffraction data is obtained by assuming the NH4+ cation to have a radius closer to that for Cs+ rather than a smaller cation such as Rb+ as often previously assumed. The alkali nitrites show an emergent length scale, attributed to the nitrogen-nitrogen spatial correlations, that depends on both temperature and the identity of the alkali cation. The corresponding nitrates show a more subtle effect in the nitrogen-nitrogen correlations. As a result, the nature of this N-N length-scale appears different for the respective nitrites and nitrates.