ISSN:
0377-0486
Schlagwort(e):
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The polycrystalline IR and Raman spectra (4000-50 cm-1) of isoelectronic K2NH(SO3)2 and K2CH2(SO3)2 have been recorded at 77 K. These salts are isomorphous at ambient temperature (space group C2/c (C2h6)) but K2NH(SO3)2 undergoes a phase change on cooling to 77 K. Possible low-temperature structures for the latter are proposed and their predicted spectra are compared with the observed spectra. The phase change appears to be limited to an ordering of hydrogen atoms to give a structure with space symmetry P1(C11) with Z = 4. To assist with the band assignment, spectra of the 2H analogues of both salts and the 15N analogue of K2NH(SO3)2 have been recorded. Aqueous solution spectra, including qualitative Raman polarization data have also been obtained for the highly soluble salts (NH4)2NH(SO3)2 and Na2CH2(SO3)2·2.5H2O and their 2H analogues. For NH(SO3)22-, the skeletal modes are assigned frequencies of 858 cm-1 (νasymN—S), 842 cm-1 (νsymN—S) and c. 180 cm-1 (δNS2). The corresponding CH2(SO3)22- frequencies are 800 cm-1 (νasymC—S), 776 cm-1 (νsymC—S) and c. 180 cm-1 (δCS2). The SO3 groups show their characteristic frequencies which are very similar for both species.
Zusätzliches Material:
9 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jrs.1250110412
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