| | 1 | Author
| E. Mikuli, A. Migdał-Mikuli, I. Natkaniec, J. Mayer | Requires cookie* | | | Title
| Phase Transitions and Water Dynamics of [Mn(H 2 0) 6 ](C10 4 ) 2 Studied by Differential Scanning Calorimetry and Neutron Scattering Methods  | | | | Abstract
| DSC measurements performed at 95 -290 K have shown that [Mn(H 2 0) 6 ](C10 4) 2 possesses, besides a high-temperature phase, existing above 323 K, four low-temperature solid phases. The inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) pat-terns registered at 20 -290 K have supported the DSC results and provided evidence that the investigated substance possesses even more than five solid phases. The IINS spectra have shown that in the room-temperature phase, water molecules perform fast stochastic reorientation at the picosecond scale. The orientational disorder characteristic for the room-temperature phase can be easily overcooled and frozen. Even by relatively slow cooling at ca. 40 K/hour a metastable, orientational (protonic) glass phase is formed below ca. 160 K. Below ca. 100 K, a structural phase transition was observed by the NPD, however the IINS spectra indicate existence of the pure ordered low-temperature phase only after annealing the sample for a few hours at 100 K. On heating, a structural phase transition takes place at ca. 120 K, and at ca. 225 K water molecules begin fast reorientation. | | | |
Reference
| Z. Naturforsch. 55a, 759—764 (2000); received July 7 2000 | | | |
Published
| 2000 | | | |
Keywords
| Hexaaquamanganese(II) chlorate(VII), Phase Transitions, DSC, Neutron Scattering | | | |
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| ZNA-2000-55a-0759 | | | | Volume
| 55 | |
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