Crystal structure analysis, pseudosymmetry and spectroscopic data of K4[Fe(CN)5NO2]⋅KNO2⋅H2O
Autor: | H. Bärnighausen, U. Himmelreich, Henning Henke, Th. Woike |
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Rok vydání: | 2002 |
Předmět: | |
Zdroj: | Zeitschrift für Kristallographie - Crystalline Materials. 217:119-126 |
ISSN: | 2196-7105 2194-4946 |
DOI: | 10.1524/zkri.217.3.119.20648 |
Popis: | K4[Fe(CN)5NO2]⋅KNO2⋅H2O crystallizes in the non-centrosymmetric orthorhombic space group Bb21 m (no. 36) with a = 2698.2(3), b = 1415.7(1), c = 849.6(1) pm and Z = 8 at 291 K. Due to a high degree of pseudosymmetry the deviations from centrosymmetry are small. The gross arrangement of the iron and potassium atoms is that of the AlB2-type, discernible from the distorted hexagons of the boron-analogous part with the composition FeK3 while further potassium atoms are replacing Al in agreement with the formulation K2[FeK3]. The disorder of the free nitrite ions affiliated to KNO2 is characterized by means of additional data sets collected at temperatures of 173 K and 363 K. The results of the structure analysis are confirmed by infra-red spectroscopy. Especially the deformation modes δ(O-N-O) of the free nitrite and those of the nitro ligand show the expected frequency splitting. Mössbauer data serve as a check on chemical composition and give an independent estimate for the mean square displacement of the iron (57Fe) atoms comparable to the results from X-ray diffraction. The loss of crystal water above 400 K is registered using ther-mogravimetry and differential scanning calorimetry. |
Databáze: | OpenAIRE |
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