Spectroscopic Implications

Via NMR and Raman spectroscopy, we can measure the solid hydrate phase. Although an overview of such spectroscopy measurements is provided in Section 6.2, some of the important results for hydrate properties in comparison to ice are provided here. 

Proton NMR spectroscopy and dielectic constant measurements provide evidence about the motion of the water molecules in crystal structures, as reviewed by Davidson and Ripmeester (1984). At very low temperatures ( 50 K) molecular motion is frozen in so that hydrate lattices become rigid. The hydrate proton NMR analysis suggests that the first-order contribution to motion is due to reorientation of water molecules in the structure the second-order contribution is due to translational diffusion at these low temperatures. 

This is one distinguishing feature between hydrates and ice water molecules diffuse two orders of magnitude slower in hydrates than in ice. As shown in Table 2.8, ice water molecules diffuse almost an order of magnitude faster than they reorient about a fixed position in the crystal structure. In direct contrast, hydrate water molecules reorient 20 times faster than they diffuse. As for all 

Crystallographic unit cell space P63/mmc Pm3n Fd3m 

Far infrared spectrum Peak at 229.3 cm 1 Peak at 229.3 cm 1 with others 

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Fischer, G. Spectroscopic Implications of Line Broadening in Large Molecules. 66,115-147 (1976). 

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Spectroscopic implications for magnetic interactions in metal complexes with nitroxide radicals (pyridylsubstituted 4,4,5,5-tetramethyl-4,5-dihydro-l//-imidazole-... 

Anomeric Effect and Electron Density Spectroscopic Implications of Anomeric Effect... 

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