scholarly journals Segmented Polyurethane Elastomers with Liquid Crystalline Hard Segments. 3. Infrared Spectroscopic Study

1995 ◽  
Vol 28 (12) ◽  
pp. 4284-4289 ◽  
Author(s):  
Weiming Tang ◽  
William J. MacKnight ◽  
Shaw L. Hsu
Keyword(s):  
Spectroscopic Study ◽  
Liquid Crystalline ◽  
Infrared Spectroscopic Study ◽  
Segmented Polyurethane ◽  
Polyurethane Elastomers ◽  
Infrared Spectroscopic ◽  
Hard Segments

Segmented Polyurethane Elastomers with Liquid Crystalline Hard Segments. 1. Synthesis and Phase Behavior

1994 ◽  
Vol 27 (10) ◽  
pp. 2814-2819 ◽  
Author(s):  
Weiming Tang ◽  
Richard J. Farris ◽  
William J. MacKnight ◽  
Claus D. Eisenbach
Keyword(s):  
Phase Behavior ◽  
Liquid Crystalline ◽  
Segmented Polyurethane ◽  
Polyurethane Elastomers ◽  
Hard Segments

Infrared spectroscopic study of the YPO4-YCrO4 system

1985 ◽  
Vol 50 (10) ◽  
pp. 2139-2145
Author(s):  
Alexander Muck ◽  
Eva Šantavá ◽  
Bohumil Hájek
Keyword(s):  
Spectroscopic Study ◽  
Infrared Spectra ◽  
Point Of View ◽  
Mixed Crystals ◽  
Crystal Symmetry ◽  
Infrared Spectroscopic Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Spectroscopic ◽  
Diffraction Patterns

The infrared spectra and powder X-ray diffraction patterns of polycrystalline YPO4-YCrO4 samples are studied from the point of view of their crystal symmetry. Mixed crystals of the D4h19 symmetry are formed over the region of 0-30 mol.% YPO4 in YCrO4. The Td → D2d → D2 or C2v(GS eff) correlation is appropriate for both PO43- and CrO43- anions.

Infrared spectroscopic study of site symmetry effects for sulphite and sulphate anions in solid sodium sulphite oxidized by air oxygen

1985 ◽  
Vol 50 (12) ◽  
pp. 2715-2721
Author(s):  
Bohumil Hájek ◽  
Alexander Muck ◽  
Eva Šantavá
Keyword(s):  
Aqueous Solution ◽  
Spectroscopic Study ◽  
Sodium Sulphite ◽  
Site Symmetry ◽  
Infrared Spectroscopic Study ◽  
Infrared Spectroscopic

The mutual replacement of SO32- and SO42- anions was studied in Na2SO3.7 H2O crystals where sulphite is slowly oxidized to sulphate by air oxygen. In a series of Na2(SO3, SO4).7 H2O samples, the C1 or Cs site symmetry appears for the SO32- anion and the site symmetry of the SO42- anion is lowered gradually from Td through D2d or C3v to C1. The replacement was also studied for anhydrous sodium sulphite obtained by dehydration or by evaporation from aqueous solution. Despite the different structures of Na2SO3 and Na2SO4 crystals (C3i1 and D2h24, respectively), the favourable dimensions of the sterically different anions allow the SO42- ions, with their own symmetry Td, to be located in the C3 sites of the SO32- ions in Na2SO3.

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