Cage occupancy and compressibility of deuterated N-2-clathrate hydrate by neutron diffraction
This paper reports pressure dependent high resolution neutron diffraction work on N2-clathrates, which for the first time provides numbers on the compressibility as well as the location and degree of filling of the guest molecules in the small and large cages. N2-clathrates crystallize, at least at...
| Main Authors: | , , , |
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| Format: | Journal article |
| Published: |
1997
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| Summary: | This paper reports pressure dependent high resolution neutron diffraction work on N2-clathrates, which for the first time provides numbers on the compressibility as well as the location and degree of filling of the guest molecules in the small and large cages. N2-clathrates crystallize, at least at lower pressures and temperatures near 0 °C, in the Stackelberg type II structure. However, during the diffraction experiments we have observed the transient and partial formation of the von Stackelberg type I N2-clathrate at pressures exceeding several hundred bar. The filling of the small cages in the type II clathrate roughly follows a Langmuir isotherm. In contrast to most previous assumptions there is strong evidence that the large cages are doubly occupied in both type I and type II N2-clathrates. The observed filling can be fitted reasonably well by a two-constant Langmuir model. |
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