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  • 1
    Electronic Resource
    Electronic Resource
    Dynamic and thermodynamic properties of clathrate hydrates (1990)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 8 (1990), S. 59-69 
    Details
    ISSN: 1573-1111
    Keywords: Clathrate hydrate ; clathrate formation ; vibrational properties ; dynamic and thermodynamic instability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Vibrational spectra and thermodynamic properties of ices and the cubic structure I (CS-I) clathrate hydrate have been studied by the lattice dynamics method. The phonon density of states for the empty hydrate framework and for xenon hydrate have been determined; the vibrational frequencies of the guest molecules in large and small cavities have been found. The stability of the hydrate with respect to the external pressure at low temperatures and its thermodynamic stability at temperatures around 0°C have been studied. It has been found that the empty hydrate framework is unstable in certain temperature and pressure regions. A definite degree of occupation of the large cavities by the guest molecules is necessary for the hydrate to become stable. It has been found that there is a maximum of the critical temperature at which the hydrate exists, which is a function of the external pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01131288
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  • 2
    Electronic Resource
    Electronic Resource
    Phase and X-ray study of clathrate formation in the tetraisoamylammonium fluoride-water system (1994)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 17 (1994), S. 137-148 
    Details
    ISSN: 1573-1111
    Keywords: Clathrate hydrate ; phase diagram ; crystal structure ; tetraisoamylammonium fluoride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The phase diagram of the binary (i-C5H11)4NF-water system has been studied in the clathrate formation region. Three polyhydrates have been discovered, two of which (1∶38.9 and 1∶32.7) are the known orthorhombic and tetragonal phases:Pbmn,a=11.88,b=21.53,c=12.70 Å,ρ means=1.019 g cm-3 (0°C), m.p.=32.4°C andP42/m, a=23.729,c=12.466 Å,ρ means=1.062 g cm-3, (0°C), m.p.=31.2°C, respectively. A single crystal X-ray analysis of the novel clathrate hydrate (i-C5H11)4NF·27 H2O is reported. This new clathrate hydrate is tetragonal,I4I/a, witha=16.894(5),c=17.111(2) Å,Z=4, (−50°C), and m.p.=34.6°C. Each (i-C5H11)4N+ cation occupies a four-chamber cavity built of 15-hedra 71635942 (idealized description), with small vacant 5444 cavities filling the intervening space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00711854
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