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Thermal analysis, phase transitions and molecular reorientations in $[Sr(OS(CH_3)_2)_6](ClO_4)_2$


Thermal analysis, phase transitions and molecular reorientations in $[Sr(OS(CH_3)_2)_6](ClO_4)_2$

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dc.contributor.author Migdał-Mikuli, Anna [SAP11005097] pl
dc.contributor.author Szostak, Elżbieta [SAP11018766] pl
dc.contributor.author Bernard, Paweł [SAP14000082] pl
dc.date.accessioned 2015-06-17T10:37:38Z
dc.date.available 2015-06-17T10:37:38Z
dc.date.issued 2014 pl
dc.identifier.issn 1388-6150 pl
dc.identifier.uri http://ruj.uj.edu.pl/xmlui/handle/item/9706
dc.language eng pl
dc.title Thermal analysis, phase transitions and molecular reorientations in $[Sr(OS(CH_3)_2)_6](ClO_4)_2$ pl
dc.type JournalArticle pl
dc.description.physical 443-449 pl
dc.abstract.en Thermal analysis (TG/DTG/QMS), performed for [Sr(OS(CH3)2)6](ClO4)2 in a flow of argon and in temperature range of 295–585 K, indicated that the compound is completely stable up to ca. 363 K, and next starts to decompose slowly, and in the temperature at ca. 492 K looses four (CH3)2SO molecules per one formula unit. During further heating [Sr(DMSO)2](ClO4)2 melts and simultaneously decomposes with explosion. Differential scanning calorimetry (DSC) measurements performed in the temperature range of 93–370 K for [Sr(DMSO)6](ClO4)2 revealed existence of the following phase transitions: glass ↔ crystal phase Cr5 at T g ≈ 164 K (235 K), phase Cr5 → phase Cr4 at Thc6 ≈ 241 K, phase Cr4 → phase Cr3 at Thc5 ≈ 255 K, phase Cr3 → phase Cr2 at Thc4 ≈ 277 K, phase Cr2 ↔ phase Cr1 at Thc3 ≈ 322 K and Tcc3 ≈ 314 K, phase Cr1 ↔ phase Rot2 at Thc2 ≈ 327 K and Tcc2 ≈ 321 K and phase Rot2 ↔ phase Rot1 at Thc1 ≈ 358 K and Tcc1 ≈ 347 K. Entropy changes values of the phase transitions at Thc1 and Thc2 (∆S ≈ 79 and 24 J mol−1 K−1, respectively) indicated that phases Rot1 and Rot2 are substantially orientationally disordered. The solid phases (Cr1–Cr5) are more or less ordered phases (∆S ≈ 7, 10, 4 and 3 J mol−1 K−1, respectively). Phase transitions in [Sr(DMSO)6](ClO4)2 were also examined by Fourier transform middle infrared spectroscopy (FT-MIR). The characteristic changes in the FT-MIR absorption spectra of the low- and high-temperature phases observed at the phase transition temperatures discovered by DSC allowed us to relate these phase transitions to the changes of the reorientational motions of DMSO ligands and/or to the crystal structure changes. pl
dc.subject.en hexadimethylsulphoxidestrontium chlorate(VII) pl
dc.subject.en thermal decomposition pl
dc.subject.en reorientational motions pl
dc.subject.en phase transitions pl
dc.subject.en DSC pl
dc.subject.en TG/DTG/QMS pl
dc.subject.en FT-MIR pl
dc.description.volume 115 pl
dc.description.number 1 pl
dc.identifier.doi 10.1007/s10973-013-3209-x pl
dc.identifier.eissn 1588-2926 pl
dc.title.journal Journal of Thermal Analysis and Calorimetry pl
dc.language.container eng pl
dc.affiliation Wydział Chemii : Zakład Dydaktyki Chemii pl
dc.subtype Article pl
dc.rights.original bez licencji pl
.pointsMNiSW [2014 A]: 25

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