The high-pressure phase diagram of ammonia dihydrate
The high-pressure phase diagram of ammonia dihydrate
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DOI：
10.1080/08957950701265029
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发表时间：
2007-01-01
影响因子：
2
通讯作者：
Fernandez-Alonso, F.
中科院分区：
文献类型：
--
作者：
Fortes, A. D.;Wood, I. G.;Fernandez-Alonso, F.
我们用粉末中子衍射法研究了二水氨(ADH)的P-T相图，Nd3中心点2D(2)O在0-9 Gpa，170-300K范围内。除了环境压力相ADH I，我们还确定了三个高压相，ADH II，III和IV，每个高压相都在至少三次不同的实验中被重现。另一种明显为体心立方的ADH相在170K时仅在6 Gpa以上观察到。ADH IV在压缩或升温时分解成高压冰相(冰VII或VIII)和一水合氨高压相(AMH V或VI)的脱水边界的存在已被证实。
We have investigated the P-T phase diagram of ammonia dihydrate (ADH), ND3 center dot 2D(2)O, using powder neutron diffraction methods over the range 0-9 GPa, 170-300 K. In addition to the ambient pressure phase, ADH I, we have identified three high-pressure phases, ADH II, III, and IV, each of which has been reproduced in at least three separate experiments. Another, apparently body-centred-cubic, phase of ADH has been observed on a single occasion above 6 GPa at 170 K. The existence of a dehydration boundary has been confirmed where, upon compression or warming, ADH IV decomposes to a high-pressure ice phase (ice VII or VIII) and a high-pressure phase of ammonia monohydrate (AMH V or VI).