title: Temperature-dependent μ-Raman investigation of struvite crystals.
abstract: The effect of temperature on the vibrational properties of struvite crystals grown from silica gels was systematically studied by μ-Raman spectroscopy. The time-dependent Raman spectra recorded in the process of long time annealing of struvite crystal at 353 K do not indicate structural changes in the struvite crystal with the time of annealing. The temperature-dependent Raman spectra recorded in the range 298-423 K reveal a phase transition in struvite at about 368 K. Above this characteristic temperature, some of bands assigned to vibrations of the PO4 and NH4 tetrahedra and water molecules observed in the Raman spectra in low temperatures (orthorhombic phase) change their spectral parameters or disappear, which indicates a transition to a higher symmetry structure of struvite in the range of high temperatures.
authors.affiliation: Institute of Physics, Lodz University of Technology, ul. Wólczańska 219, 93-005 Łódź, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Prywer
authors.affiliation: Faculty of Technical Physics, Poznan University of Technology, ul. Piotrowo 3, 60-965 Poznań, Poland.
authors.forename: D
authors.initials: D
authors.lastname: Kasprowicz
authors.affiliation: Faculty of Technical Physics, Poznan University of Technology, ul. Piotrowo 3, 60-965 Poznań, Poland.
authors.forename: T
authors.initials: T
authors.lastname: Runka
keywords: Magnesium ammonium phosphate hexahydrate; Physical properties; Raman spectra; Struvite