Pressure-induced phase changes of argon hydrate and methane hydrate at room temperature
Pressure-induced phase changes of argon hydrate and methane hydrate at room temperature
复制标题
室温下水合氩和甲烷水合物压力诱导的相变
DOI：
10.2183/pjab.78.39
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
T. Yagi
中科院分区：
文献类型：
--
作者：
H. Hirai;Yukako Uchihara;T. Kawamura;Y. Yamamoto;T. Yagi
采用金刚石顶压室，在0.2~10.0 Gpa的压力范围内，进行了室温下的水合物高压实验。原位X射线衍射仪和光学显微镜研究表明，在高达6.5 Gpa的压力下，水合物中存在两种高压结构，即原始的四方结构和体心正交相结构。结构分析表明，四方结构仅由容纳两个Ar原子的14面体组成，体心正交体结构属于“填充冰”结构，即水-客体体系中的一种新型结构。对于甲烷水合物，发现了三种高压结构，即六方结构、原始正交结构和体心正交结构。结构分析表明，该六方结构是在常压下报道的一种改进的六方结构，而后者是一种“填充冰”结构。
High-pressure experiments of argon hydrate and methane hydrate were performed using a diamond anvil cell in a pressure range of 0.2 to 10.0GPa at room temperature. In-situ X-ray diffractometry and optical microscopy revealed that two high pressure structures of argon hydrate, a primitive tetragonal structure and a body-centered orthorhombic structure, existed under pressures of up to 6.5GPa. The structural analysis showed that the tetragonal structure was composed solely of 14-hedra accommodating two argon atoms, and that the body-centered orthorhombic structure belonged to a“filled-ice”structure, i.e., a new type of structure in a water-guest system. As for methane hydrate, three high-pressure structures, a hexagonal structure, a primitive orthorhombic structure, and a body-centered orthorhombic structure, were found. The structural analysis indicated that the hexagonal structure was a modified structure of a hexagonal one reported at ambient pressure, and that the latter orthorhombic structure was the“filled-ice”structure.