Cubic ice Ic without stacking defects obtained from ice XVII
Cubic ice Ic without stacking defects obtained from ice XVII
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DOI：
10.1038/s41563-020-0606-y
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发表时间：
2020-02-03
期刊：
影响因子：
41.2
通讯作者：
Ulivi, Lorenzo
中科院分区：
文献类型：
--
作者：
del Rosso, Leonardo;Celli, Milva;Ulivi, Lorenzo
结构纯立方冰 Ic 是通过 D2O 冰 XVII 的受控加热获得的。在超过 18 种不同形式的水冰中，只有常见的六方相和立方相存在于地球上的自然界中。尽管如此，现在人们普遍认识到，迄今为止发现的所有“立方冰”样本并不具有完全立方晶体结构，而是冰I（即冰Isd）的堆积无序形式，其中包含氢键水分子的六方和立方堆积序列。在这里，我们描述了一种获得大量具有高结构纯度的立方冰 Ic 的方法。立方冰 Ic 是通过加热由原始 C-0 水合物样品在动态真空下退火获得的 D2O 冰 XVII 粉末形成的。在两种不同仪器上进行的中子衍射实验和拉曼光谱测量证实了立方冰 Ic 的结构纯度。这些发现有助于更好地了解冰 I 多态性和两种天然冰形式的存在。
Structurally pure cubic ice Ic is obtained from the controlled heating of D2O ice XVII.Amongst the more than 18 different forms of water ice, only the common hexagonal phase and the cubic phase are present in nature on Earth. Nonetheless, it is now widely recognized that all samples of 'cubic ice' discovered so far do not have a fully cubic crystal structure but instead are stacking-disordered forms of ice I (namely, ice Isd), which contain both hexagonal and cubic stacking sequences of hydrogen-bonded water molecules. Here, we describe a method to obtain large quantities of cubic ice Ic with high structural purity. Cubic ice Ic is formed by heating a powder of D2O ice XVII obtained from annealing of pristine C-0 hydrate samples under dynamic vacuum. Neutron diffraction experiments performed on two different instruments and Raman spectroscopy measurements confirm the structural purity of the cubic ice, Ic. These findings contribute to a better understanding of ice I polymorphism and the existence of the two natural ice forms.